Merge branch 'release/v1.22.0'

2026-06-20 00:15:29 +02:00 · 2025-01-26 13:37:04 +13:00
parent 7703d09919 04410ff463
commit 9687329fc1
25 changed files with 1715 additions and 737 deletions
@@ -2,6 +2,22 @@

 Notable changes to Mailpit will be documented in this file.

+## [v1.22.0]
+
+### Feature
+- SMTP auto-forwarding option ([#414](https://github.com/axllent/mailpit/issues/414))
+- Option to override the From email address in SMTP relay configuration ([#414](https://github.com/axllent/mailpit/issues/414))
+- Add Chaos functionality to test integration handling of SMTP error responses ([#402](https://github.com/axllent/mailpit/issues/402), [#110](https://github.com/axllent/mailpit/issues/110), [#144](https://github.com/axllent/mailpit/issues/144) & [#268](https://github.com/axllent/mailpit/issues/268))
+
+### Chore
+- Update node dependencies
+- Update Go dependencies
+
+### Fix
+- Update command `npm run update-caniemail` save path ([#422](https://github.com/axllent/mailpit/issues/422))
+- Correct date formatting in TestMakeHeaders
+
+
 ## [v1.21.8]

 ### Chore
@@ -46,8 +46,10 @@ including image thumbnails), including optional [HTTPS](https://mailpit.axllent.
 - Mobile and tablet HTML preview toggle in desktop mode
 - [Message tagging](https://mailpit.axllent.org/docs/usage/tagging/) including manual tagging or automated tagging using filtering and "plus addressing"
 - [SMTP relaying](https://mailpit.axllent.org/docs/configuration/smtp-relay/) (message release) - relay messages via a different SMTP server including an optional allowlist of accepted recipients
+- [SMTP forwarding](https://mailpit.axllent.org/docs/configuration/smtp-forward/) - automatically forward messages via a different SMTP server to predefined email addresses
 - Fast message [storing & processing](https://mailpit.axllent.org/docs/configuration/email-storage/) - ingesting 100-200 emails per second over SMTP depending on CPU, network speed & email size,
 easily handling tens of thousands of emails, with automatic email pruning (by default keeping the most recent 500 emails)
+- [Chaos](ttps://mailpit.axllent.org/docs/integration/chaos/) feature to enable configurable SMTP errors to test application resilience
 - `List-Unsubscribe` syntax validation
 - Optional [webhook](https://mailpit.axllent.org/docs/integration/webhook/) for received messages

@@ -10,6 +10,7 @@ import (
 	"github.com/axllent/mailpit/internal/auth"
 	"github.com/axllent/mailpit/internal/logger"
 	"github.com/axllent/mailpit/internal/smtpd"
+	"github.com/axllent/mailpit/internal/smtpd/chaos"
 	"github.com/axllent/mailpit/internal/storage"
 	"github.com/axllent/mailpit/internal/tools"
 	"github.com/axllent/mailpit/server"
@@ -122,6 +123,13 @@ func init() {
 	rootCmd.Flags().BoolVar(&config.SMTPRelayAll, "smtp-relay-all", config.SMTPRelayAll, "Auto-relay all new messages via external SMTP server (caution!)")
 	rootCmd.Flags().StringVar(&config.SMTPRelayMatching, "smtp-relay-matching", config.SMTPRelayMatching, "Auto-relay new messages to only matching recipients (regular expression)")

+	// SMTP forwarding
+	rootCmd.Flags().StringVar(&config.SMTPForwardConfigFile, "smtp-forward-config", config.SMTPForwardConfigFile, "SMTP forwarding configuration file for all messages")
+
+	// Chaos
+	rootCmd.Flags().BoolVar(&chaos.Enabled, "enable-chaos", chaos.Enabled, "Enable Chaos functionality (API / web UI)")
+	rootCmd.Flags().StringVar(&config.ChaosTriggers, "chaos-triggers", config.ChaosTriggers, "Enable Chaos & set the triggers for SMTP server")
+
 	// POP3 server
 	rootCmd.Flags().StringVar(&config.POP3Listen, "pop3", config.POP3Listen, "POP3 server bind interface and port")
 	rootCmd.Flags().StringVar(&config.POP3AuthFile, "pop3-auth-file", config.POP3AuthFile, "A password file for POP3 server authentication (enables POP3 server)")
@@ -208,7 +216,7 @@ func initConfigFromEnv() {
 	}
 	config.UIAuthFile = os.Getenv("MP_UI_AUTH_FILE")
 	if err := auth.SetUIAuth(os.Getenv("MP_UI_AUTH")); err != nil {
-		logger.Log().Errorf(err.Error())
+		logger.Log().Error(err.Error())
 	}
 	config.UITLSCert = os.Getenv("MP_UI_TLS_CERT")
 	config.UITLSKey = os.Getenv("MP_UI_TLS_KEY")
@@ -231,7 +239,7 @@ func initConfigFromEnv() {
 	}
 	config.SMTPAuthFile = os.Getenv("MP_SMTP_AUTH_FILE")
 	if err := auth.SetSMTPAuth(os.Getenv("MP_SMTP_AUTH")); err != nil {
-		logger.Log().Errorf(err.Error())
+		logger.Log().Error(err.Error())
 	}
 	if getEnabledFromEnv("MP_SMTP_AUTH_ACCEPT_ANY") {
 		config.SMTPAuthAcceptAny = true
@@ -278,16 +286,38 @@ func initConfigFromEnv() {
 	config.SMTPRelayConfig.Password = os.Getenv("MP_SMTP_RELAY_PASSWORD")
 	config.SMTPRelayConfig.Secret = os.Getenv("MP_SMTP_RELAY_SECRET")
 	config.SMTPRelayConfig.ReturnPath = os.Getenv("MP_SMTP_RELAY_RETURN_PATH")
+	config.SMTPRelayConfig.OverrideFrom = os.Getenv("MP_SMTP_RELAY_OVERRIDE_FROM")
 	config.SMTPRelayConfig.AllowedRecipients = os.Getenv("MP_SMTP_RELAY_ALLOWED_RECIPIENTS")
 	config.SMTPRelayConfig.BlockedRecipients = os.Getenv("MP_SMTP_RELAY_BLOCKED_RECIPIENTS")

+	// SMTP forwarding
+	config.SMTPForwardConfigFile = os.Getenv("MP_SMTP_FORWARD_CONFIG")
+	config.SMTPForwardConfig = config.SMTPForwardConfigStruct{}
+	config.SMTPForwardConfig.Host = os.Getenv("MP_SMTP_FORWARD_HOST")
+	if len(os.Getenv("MP_SMTP_FORWARD_PORT")) > 0 {
+		config.SMTPForwardConfig.Port, _ = strconv.Atoi(os.Getenv("MP_SMTP_FORWARD_PORT"))
+	}
+	config.SMTPForwardConfig.STARTTLS = getEnabledFromEnv("MP_SMTP_FORWARD_STARTTLS")
+	config.SMTPForwardConfig.AllowInsecure = getEnabledFromEnv("MP_SMTP_FORWARD_ALLOW_INSECURE")
+	config.SMTPForwardConfig.Auth = os.Getenv("MP_SMTP_FORWARD_AUTH")
+	config.SMTPForwardConfig.Username = os.Getenv("MP_SMTP_FORWARD_USERNAME")
+	config.SMTPForwardConfig.Password = os.Getenv("MP_SMTP_FORWARD_PASSWORD")
+	config.SMTPForwardConfig.Secret = os.Getenv("MP_SMTP_FORWARD_SECRET")
+	config.SMTPForwardConfig.ReturnPath = os.Getenv("MP_SMTP_FORWARD_RETURN_PATH")
+	config.SMTPForwardConfig.OverrideFrom = os.Getenv("MP_SMTP_FORWARD_OVERRIDE_FROM")
+	config.SMTPForwardConfig.To = os.Getenv("MP_SMTP_FORWARD_TO")
+
+	// Chaos
+	chaos.Enabled = getEnabledFromEnv("MP_ENABLE_CHAOS")
+	config.ChaosTriggers = os.Getenv("MP_CHAOS_TRIGGERS")
+
 	// POP3 server
 	if len(os.Getenv("MP_POP3_BIND_ADDR")) > 0 {
 		config.POP3Listen = os.Getenv("MP_POP3_BIND_ADDR")
 	}
 	config.POP3AuthFile = os.Getenv("MP_POP3_AUTH_FILE")
 	if err := auth.SetPOP3Auth(os.Getenv("MP_POP3_AUTH")); err != nil {
-		logger.Log().Errorf(err.Error())
+		logger.Log().Error(err.Error())
 	}
 	config.POP3TLSCert = os.Getenv("MP_POP3_TLS_CERT")
 	config.POP3TLSKey = os.Getenv("MP_POP3_TLS_KEY")
@@ -5,19 +5,17 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"net/url"
 	"os"
 	"path"
 	"path/filepath"
 	"regexp"
-	"strconv"
 	"strings"

 	"github.com/axllent/mailpit/internal/auth"
 	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/smtpd/chaos"
 	"github.com/axllent/mailpit/internal/spamassassin"
 	"github.com/axllent/mailpit/internal/tools"
-	"gopkg.in/yaml.v3"
 )

 var (
@@ -114,22 +112,12 @@ var (
 	// including x-tags & plus-addresses
 	TagsDisable string

-	// SMTPRelayConfigFile to parse a yaml file and store config of relay SMTP server
+	// SMTPRelayConfigFile to parse a yaml file and store config of the relay SMTP server
 	SMTPRelayConfigFile string

-	// SMTPRelayConfig to parse a yaml file and store config of relay SMTP server
+	// SMTPRelayConfig to parse a yaml file and store config of the the relay SMTP server
 	SMTPRelayConfig SMTPRelayConfigStruct

-	// SMTPStrictRFCHeaders will return an error if the email headers contain <CR><CR><LF> (\r\r\n)
-	// @see https://github.com/axllent/mailpit/issues/87 & https://github.com/axllent/mailpit/issues/153
-	SMTPStrictRFCHeaders bool
-
-	// SMTPAllowedRecipients if set, will only accept recipients matching this regular expression
-	SMTPAllowedRecipients string
-
-	// SMTPAllowedRecipientsRegexp is the compiled version of SMTPAllowedRecipients
-	SMTPAllowedRecipientsRegexp *regexp.Regexp
-
 	// ReleaseEnabled is whether message releases are enabled, requires a valid SMTPRelayConfigFile
 	ReleaseEnabled = false

@@ -143,6 +131,22 @@ var (
 	// SMTPRelayMatchingRegexp is the compiled version of SMTPRelayMatching
 	SMTPRelayMatchingRegexp *regexp.Regexp

+	// SMTPForwardConfigFile to parse a yaml file and store config of the forwarding SMTP server
+	SMTPForwardConfigFile string
+
+	// SMTPForwardConfig to parse a yaml file and store config of the forwarding SMTP server
+	SMTPForwardConfig SMTPForwardConfigStruct
+
+	// SMTPStrictRFCHeaders will return an error if the email headers contain <CR><CR><LF> (\r\r\n)
+	// @see https://github.com/axllent/mailpit/issues/87 & https://github.com/axllent/mailpit/issues/153
+	SMTPStrictRFCHeaders bool
+
+	// SMTPAllowedRecipients if set, will only accept recipients matching this regular expression
+	SMTPAllowedRecipients string
+
+	// SMTPAllowedRecipientsRegexp is the compiled version of SMTPAllowedRecipients
+	SMTPAllowedRecipientsRegexp *regexp.Regexp
+
 	// POP3Listen address - if set then Mailpit will start the POP3 server and listen on this address
 	POP3Listen = "[::]:1110"

@@ -176,6 +180,9 @@ var (
 	// RepoBinaryName on Github for updater
 	RepoBinaryName = "mailpit"

+	// ChaosTriggers are parsed and set in the chaos module
+	ChaosTriggers string
+
 	// DisableHTMLCheck DEPRECATED 2024/04/13 - kept here to display console warning only
 	DisableHTMLCheck = false

@@ -200,6 +207,7 @@ type SMTPRelayConfigStruct struct {
 	Password                string         `yaml:"password"`           // plain
 	Secret                  string         `yaml:"secret"`             // cram-md5
 	ReturnPath              string         `yaml:"return-path"`        // allow overriding the bounce address
+	OverrideFrom            string         `yaml:"override-from"`      // allow overriding of the from address
 	AllowedRecipients       string         `yaml:"allowed-recipients"` // regex, if set needs to match for mails to be relayed
 	AllowedRecipientsRegexp *regexp.Regexp // compiled regexp using AllowedRecipients
 	BlockedRecipients       string         `yaml:"blocked-recipients"` // regex, if set prevents relating to these addresses
@@ -209,6 +217,21 @@ type SMTPRelayConfigStruct struct {
 	RecipientAllowlist string `yaml:"recipient-allowlist"`
 }

+// SMTPForwardConfigStruct struct for parsing yaml & storing variables
+type SMTPForwardConfigStruct struct {
+	To            string `yaml:"to"`             // comma-separated list of email addresses
+	Host          string `yaml:"host"`           // SMTP host
+	Port          int    `yaml:"port"`           // SMTP port
+	STARTTLS      bool   `yaml:"starttls"`       // whether to use STARTTLS
+	AllowInsecure bool   `yaml:"allow-insecure"` // allow insecure authentication
+	Auth          string `yaml:"auth"`           // none, plain, login, cram-md5
+	Username      string `yaml:"username"`       // plain & cram-md5
+	Password      string `yaml:"password"`       // plain
+	Secret        string `yaml:"secret"`         // cram-md5
+	ReturnPath    string `yaml:"return-path"`    // allow overriding the bounce address
+	OverrideFrom  string `yaml:"override-from"`  // allow overriding of the from address
+}
+
 // VerifyConfig wil do some basic checking
 func VerifyConfig() error {
 	cssFontRestriction := "*"
@@ -344,6 +367,14 @@ func VerifyConfig() error {
 		return errors.New("[smtp] authentication requires STARTTLS or TLS encryption, run with `--smtp-auth-allow-insecure` to allow insecure authentication")
 	}

+	if err := parseChaosTriggers(); err != nil {
+		return fmt.Errorf("[chaos] %s", err.Error())
+	}
+
+	if chaos.Enabled {
+		logger.Log().Info("[chaos] is enabled")
+	}
+
 	// POP3 server
 	if POP3TLSCert != "" {
 		POP3TLSCert = filepath.Clean(POP3TLSCert)
@@ -465,6 +496,15 @@ func VerifyConfig() error {
 		logger.Log().Warnf("[relay] auto-relaying all new messages via %s:%d", SMTPRelayConfig.Host, SMTPRelayConfig.Port)
 	}

+	if err := parseForwardConfig(SMTPForwardConfigFile); err != nil {
+		return err
+	}
+
+	// separate forwarding config validation to account for environment variables
+	if err := validateForwardConfig(); err != nil {
+		return err
+	}
+
 	if DemoMode {
 		MaxMessages = 1000
 		// this deserves a warning
@@ -473,171 +513,3 @@ func VerifyConfig() error {

 	return nil
 }
-
-// Parse the --max-age value (if set)
-func parseMaxAge() error {
-	if MaxAge == "" {
-		return nil
-	}
-
-	re := regexp.MustCompile(`^\d+(h|d)$`)
-	if !re.MatchString(MaxAge) {
-		return fmt.Errorf("max-age must be either <int>h for hours or <int>d for days: %s", MaxAge)
-	}
-
-	if strings.HasSuffix(MaxAge, "h") {
-		hours, err := strconv.Atoi(strings.TrimSuffix(MaxAge, "h"))
-		if err != nil {
-			return err
-		}
-
-		MaxAgeInHours = hours
-
-		return nil
-	}
-
-	days, err := strconv.Atoi(strings.TrimSuffix(MaxAge, "d"))
-	if err != nil {
-		return err
-	}
-
-	logger.Log().Debugf("[db] auto-deleting messages older than %s", MaxAge)
-
-	MaxAgeInHours = days * 24
-	return nil
-}
-
-// Parse the SMTPRelayConfigFile (if set)
-func parseRelayConfig(c string) error {
-	if c == "" {
-		return nil
-	}
-
-	c = filepath.Clean(c)
-
-	if !isFile(c) {
-		return fmt.Errorf("[smtp] relay configuration not found or readable: %s", c)
-	}
-
-	data, err := os.ReadFile(c)
-	if err != nil {
-		return err
-	}
-
-	if err := yaml.Unmarshal(data, &SMTPRelayConfig); err != nil {
-		return err
-	}
-
-	if SMTPRelayConfig.Host == "" {
-		return errors.New("[smtp] relay host not set")
-	}
-
-	// DEPRECATED 2024/03/12
-	if SMTPRelayConfig.RecipientAllowlist != "" {
-		logger.Log().Warn("[smtp] relay 'recipient-allowlist' is deprecated, use 'allowed-recipients' instead")
-		if SMTPRelayConfig.AllowedRecipients == "" {
-			SMTPRelayConfig.AllowedRecipients = SMTPRelayConfig.RecipientAllowlist
-		}
-	}
-
-	return nil
-}
-
-// Validate the SMTPRelayConfig (if Host is set)
-func validateRelayConfig() error {
-	if SMTPRelayConfig.Host == "" {
-		return nil
-	}
-
-	if SMTPRelayConfig.Port == 0 {
-		SMTPRelayConfig.Port = 25 // default
-	}
-
-	SMTPRelayConfig.Auth = strings.ToLower(SMTPRelayConfig.Auth)
-
-	if SMTPRelayConfig.Auth == "" || SMTPRelayConfig.Auth == "none" || SMTPRelayConfig.Auth == "false" {
-		SMTPRelayConfig.Auth = "none"
-	} else if SMTPRelayConfig.Auth == "plain" {
-		if SMTPRelayConfig.Username == "" || SMTPRelayConfig.Password == "" {
-			return fmt.Errorf("[smtp] relay host username or password not set for PLAIN authentication")
-		}
-	} else if SMTPRelayConfig.Auth == "login" {
-		SMTPRelayConfig.Auth = "login"
-		if SMTPRelayConfig.Username == "" || SMTPRelayConfig.Password == "" {
-			return fmt.Errorf("[smtp] relay host username or password not set for LOGIN authentication")
-		}
-	} else if strings.HasPrefix(SMTPRelayConfig.Auth, "cram") {
-		SMTPRelayConfig.Auth = "cram-md5"
-		if SMTPRelayConfig.Username == "" || SMTPRelayConfig.Secret == "" {
-			return fmt.Errorf("[smtp] relay host username or secret not set for CRAM-MD5 authentication")
-		}
-	} else {
-		return fmt.Errorf("[smtp] relay authentication method not supported: %s", SMTPRelayConfig.Auth)
-	}
-
-	ReleaseEnabled = true
-
-	logger.Log().Infof("[smtp] enabling message relaying via %s:%d", SMTPRelayConfig.Host, SMTPRelayConfig.Port)
-
-	if SMTPRelayConfig.AllowedRecipients != "" {
-		re, err := regexp.Compile(SMTPRelayConfig.AllowedRecipients)
-		if err != nil {
-			return fmt.Errorf("[smtp] failed to compile relay recipient allowlist regexp: %s", err.Error())
-		}
-
-		SMTPRelayConfig.AllowedRecipientsRegexp = re
-		logger.Log().Infof("[smtp] relay recipient allowlist is active with the following regexp: %s", SMTPRelayConfig.AllowedRecipients)
-	}
-
-	if SMTPRelayConfig.BlockedRecipients != "" {
-		re, err := regexp.Compile(SMTPRelayConfig.BlockedRecipients)
-		if err != nil {
-			return fmt.Errorf("[smtp] failed to compile relay recipient blocklist regexp: %s", err.Error())
-		}
-
-		SMTPRelayConfig.BlockedRecipientsRegexp = re
-		logger.Log().Infof("[smtp] relay recipient blocklist is active with the following regexp: %s", SMTPRelayConfig.BlockedRecipients)
-	}
-
-	return nil
-}
-
-// IsFile returns whether a file exists and is readable
-func isFile(path string) bool {
-	f, err := os.Open(filepath.Clean(path))
-	defer f.Close()
-	return err == nil
-}
-
-// IsDir returns whether a path is a directory
-func isDir(path string) bool {
-	info, err := os.Stat(path)
-	if err != nil || os.IsNotExist(err) || !info.IsDir() {
-		return false
-	}
-
-	return true
-}
-
-func isValidURL(s string) bool {
-	u, err := url.ParseRequestURI(s)
-	if err != nil {
-		return false
-	}
-
-	return strings.HasPrefix(u.Scheme, "http")
-}
-
-// DBTenantID converts a tenant ID to a DB-friendly value if set
-func DBTenantID(s string) string {
-	s = tools.Normalize(s)
-	if s != "" {
-		re := regexp.MustCompile(`[^a-zA-Z0-9\_]`)
-		s = re.ReplaceAllString(s, "_")
-		if !strings.HasSuffix(s, "_") {
-			s = s + "_"
-		}
-	}
-
-	return s
-}
@@ -0,0 +1,51 @@
+package config
+
+import (
+	"net/url"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/axllent/mailpit/internal/tools"
+)
+
+// IsFile returns whether a file exists and is readable
+func isFile(path string) bool {
+	f, err := os.Open(filepath.Clean(path))
+	defer f.Close()
+	return err == nil
+}
+
+// IsDir returns whether a path is a directory
+func isDir(path string) bool {
+	info, err := os.Stat(path)
+	if err != nil || os.IsNotExist(err) || !info.IsDir() {
+		return false
+	}
+
+	return true
+}
+
+func isValidURL(s string) bool {
+	u, err := url.ParseRequestURI(s)
+	if err != nil {
+		return false
+	}
+
+	return strings.HasPrefix(u.Scheme, "http")
+}
+
+// DBTenantID converts a tenant ID to a DB-friendly value if set
+func DBTenantID(s string) string {
+	s = tools.Normalize(s)
+	if s != "" {
+		re := regexp.MustCompile(`[^a-zA-Z0-9\_]`)
+		s = re.ReplaceAllString(s, "_")
+		if !strings.HasSuffix(s, "_") {
+			s = s + "_"
+		}
+	}
+
+	return s
+}
@@ -0,0 +1,282 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"net/mail"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/smtpd/chaos"
+	"gopkg.in/yaml.v3"
+)
+
+// Parse the --max-age value (if set)
+func parseMaxAge() error {
+	if MaxAge == "" {
+		return nil
+	}
+
+	re := regexp.MustCompile(`^\d+(h|d)$`)
+	if !re.MatchString(MaxAge) {
+		return fmt.Errorf("max-age must be either <int>h for hours or <int>d for days: %s", MaxAge)
+	}
+
+	if strings.HasSuffix(MaxAge, "h") {
+		hours, err := strconv.Atoi(strings.TrimSuffix(MaxAge, "h"))
+		if err != nil {
+			return err
+		}
+
+		MaxAgeInHours = hours
+
+		return nil
+	}
+
+	days, err := strconv.Atoi(strings.TrimSuffix(MaxAge, "d"))
+	if err != nil {
+		return err
+	}
+
+	logger.Log().Debugf("[db] auto-deleting messages older than %s", MaxAge)
+
+	MaxAgeInHours = days * 24
+	return nil
+}
+
+// Parse the SMTPRelayConfigFile (if set)
+func parseRelayConfig(c string) error {
+	if c == "" {
+		return nil
+	}
+
+	c = filepath.Clean(c)
+
+	if !isFile(c) {
+		return fmt.Errorf("[relay] configuration not found or readable: %s", c)
+	}
+
+	data, err := os.ReadFile(c)
+	if err != nil {
+		return err
+	}
+
+	if err := yaml.Unmarshal(data, &SMTPRelayConfig); err != nil {
+		return err
+	}
+
+	if SMTPRelayConfig.Host == "" {
+		return errors.New("[relay] host not set")
+	}
+
+	// DEPRECATED 2024/03/12
+	if SMTPRelayConfig.RecipientAllowlist != "" {
+		logger.Log().Warn("[relay] 'recipient-allowlist' is deprecated, use 'allowed-recipients' instead")
+		if SMTPRelayConfig.AllowedRecipients == "" {
+			SMTPRelayConfig.AllowedRecipients = SMTPRelayConfig.RecipientAllowlist
+		}
+	}
+
+	return nil
+}
+
+// Validate the SMTPRelayConfig (if Host is set)
+func validateRelayConfig() error {
+	if SMTPRelayConfig.Host == "" {
+		return nil
+	}
+
+	if SMTPRelayConfig.Port == 0 {
+		SMTPRelayConfig.Port = 25 // default
+	}
+
+	SMTPRelayConfig.Auth = strings.ToLower(SMTPRelayConfig.Auth)
+
+	if SMTPRelayConfig.Auth == "" || SMTPRelayConfig.Auth == "none" || SMTPRelayConfig.Auth == "false" {
+		SMTPRelayConfig.Auth = "none"
+	} else if SMTPRelayConfig.Auth == "plain" {
+		if SMTPRelayConfig.Username == "" || SMTPRelayConfig.Password == "" {
+			return fmt.Errorf("[relay] host username or password not set for PLAIN authentication")
+		}
+	} else if SMTPRelayConfig.Auth == "login" {
+		SMTPRelayConfig.Auth = "login"
+		if SMTPRelayConfig.Username == "" || SMTPRelayConfig.Password == "" {
+			return fmt.Errorf("[relay] host username or password not set for LOGIN authentication")
+		}
+	} else if strings.HasPrefix(SMTPRelayConfig.Auth, "cram") {
+		SMTPRelayConfig.Auth = "cram-md5"
+		if SMTPRelayConfig.Username == "" || SMTPRelayConfig.Secret == "" {
+			return fmt.Errorf("[relay] host username or secret not set for CRAM-MD5 authentication")
+		}
+	} else {
+		return fmt.Errorf("[relay] authentication method not supported: %s", SMTPRelayConfig.Auth)
+	}
+
+	if SMTPRelayConfig.AllowedRecipients != "" {
+		re, err := regexp.Compile(SMTPRelayConfig.AllowedRecipients)
+		if err != nil {
+			return fmt.Errorf("[relay] failed to compile recipient allowlist regexp: %s", err.Error())
+		}
+
+		SMTPRelayConfig.AllowedRecipientsRegexp = re
+		logger.Log().Infof("[relay] recipient allowlist is active with the following regexp: %s", SMTPRelayConfig.AllowedRecipients)
+	}
+
+	if SMTPRelayConfig.BlockedRecipients != "" {
+		re, err := regexp.Compile(SMTPRelayConfig.BlockedRecipients)
+		if err != nil {
+			return fmt.Errorf("[relay] failed to compile recipient blocklist regexp: %s", err.Error())
+		}
+
+		SMTPRelayConfig.BlockedRecipientsRegexp = re
+		logger.Log().Infof("[relay] recipient blocklist is active with the following regexp: %s", SMTPRelayConfig.BlockedRecipients)
+	}
+
+	if SMTPRelayConfig.OverrideFrom != "" {
+		m, err := mail.ParseAddress(SMTPRelayConfig.OverrideFrom)
+		if err != nil {
+			return fmt.Errorf("[relay] override-from is not a valid email address: %s", SMTPRelayConfig.OverrideFrom)
+		}
+
+		SMTPRelayConfig.OverrideFrom = m.Address
+	}
+
+	ReleaseEnabled = true
+
+	logger.Log().Infof("[relay] enabling message relaying via %s:%d", SMTPRelayConfig.Host, SMTPRelayConfig.Port)
+
+	return nil
+}
+
+// Parse the SMTPForwardConfigFile (if set)
+func parseForwardConfig(c string) error {
+	if c == "" {
+		return nil
+	}
+
+	c = filepath.Clean(c)
+
+	if !isFile(c) {
+		return fmt.Errorf("[forward] configuration not found or readable: %s", c)
+	}
+
+	data, err := os.ReadFile(c)
+	if err != nil {
+		return err
+	}
+
+	if err := yaml.Unmarshal(data, &SMTPForwardConfig); err != nil {
+		return err
+	}
+
+	if SMTPForwardConfig.Host == "" {
+		return errors.New("[forward] host not set")
+	}
+
+	return nil
+}
+
+// Validate the SMTPForwardConfig (if Host is set)
+func validateForwardConfig() error {
+	if SMTPForwardConfig.Host == "" {
+		return nil
+	}
+
+	if SMTPForwardConfig.Port == 0 {
+		SMTPForwardConfig.Port = 25 // default
+	}
+
+	SMTPForwardConfig.Auth = strings.ToLower(SMTPForwardConfig.Auth)
+
+	if SMTPForwardConfig.Auth == "" || SMTPForwardConfig.Auth == "none" || SMTPForwardConfig.Auth == "false" {
+		SMTPForwardConfig.Auth = "none"
+	} else if SMTPForwardConfig.Auth == "plain" {
+		if SMTPForwardConfig.Username == "" || SMTPForwardConfig.Password == "" {
+			return fmt.Errorf("[forward] host username or password not set for PLAIN authentication")
+		}
+	} else if SMTPForwardConfig.Auth == "login" {
+		SMTPForwardConfig.Auth = "login"
+		if SMTPForwardConfig.Username == "" || SMTPForwardConfig.Password == "" {
+			return fmt.Errorf("[forward] host username or password not set for LOGIN authentication")
+		}
+	} else if strings.HasPrefix(SMTPForwardConfig.Auth, "cram") {
+		SMTPForwardConfig.Auth = "cram-md5"
+		if SMTPForwardConfig.Username == "" || SMTPForwardConfig.Secret == "" {
+			return fmt.Errorf("[forward] host username or secret not set for CRAM-MD5 authentication")
+		}
+	} else {
+		return fmt.Errorf("[forward] authentication method not supported: %s", SMTPForwardConfig.Auth)
+	}
+
+	if SMTPForwardConfig.To == "" {
+		return errors.New("[forward] To addresses missing")
+	}
+
+	to := []string{}
+	addresses := strings.Split(SMTPForwardConfig.To, ",")
+	for _, a := range addresses {
+		a = strings.TrimSpace(a)
+		m, err := mail.ParseAddress(a)
+		if err != nil {
+			return fmt.Errorf("[forward] To address is not a valid email address: %s", a)
+		}
+		to = append(to, m.Address)
+	}
+
+	if len(to) == 0 {
+		return errors.New("[forward] no valid To addresses found")
+	}
+
+	// overwrite the To field with the cleaned up list
+	SMTPForwardConfig.To = strings.Join(to, ",")
+
+	if SMTPForwardConfig.OverrideFrom != "" {
+		m, err := mail.ParseAddress(SMTPForwardConfig.OverrideFrom)
+		if err != nil {
+			return fmt.Errorf("[forward] override-from is not a valid email address: %s", SMTPForwardConfig.OverrideFrom)
+		}
+
+		SMTPForwardConfig.OverrideFrom = m.Address
+	}
+
+	logger.Log().Infof("[forward] enabling message forwarding to %s via %s:%d", SMTPForwardConfig.To, SMTPForwardConfig.Host, SMTPForwardConfig.Port)
+
+	return nil
+}
+
+func parseChaosTriggers() error {
+	if ChaosTriggers == "" {
+		return nil
+	}
+
+	re := regexp.MustCompile(`^([a-zA-Z0-0]+):(\d\d\d):(\d+(\.\d)?)$`)
+
+	parts := strings.Split(ChaosTriggers, ",")
+	for _, p := range parts {
+		p = strings.TrimSpace(p)
+		if !re.MatchString(p) {
+			return fmt.Errorf("invalid argument: %s", p)
+		}
+
+		matches := re.FindAllStringSubmatch(p, 1)
+		key := matches[0][1]
+		errorCode, err := strconv.Atoi(matches[0][2])
+		if err != nil {
+			return err
+		}
+		probability, err := strconv.Atoi(matches[0][3])
+		if err != nil {
+			return err
+		}
+
+		if err := chaos.Set(key, errorCode, probability); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
@@ -5,7 +5,7 @@ go 1.23
 toolchain go1.23.2

 require (
-	github.com/PuerkitoBio/goquery v1.10.0
+	github.com/PuerkitoBio/goquery v1.10.1
 	github.com/araddon/dateparse v0.0.0-20210429162001-6b43995a97de
 	github.com/axllent/semver v0.0.1
 	github.com/gomarkdown/markdown v0.0.0-20241205020045-f7e15b2f3e62
@@ -23,11 +23,11 @@ require (
 	github.com/spf13/pflag v1.0.5
 	github.com/tg123/go-htpasswd v1.2.3
 	github.com/vanng822/go-premailer v1.22.0
-	golang.org/x/net v0.33.0
+	golang.org/x/net v0.34.0
 	golang.org/x/text v0.21.0
-	golang.org/x/time v0.8.0
+	golang.org/x/time v0.9.0
 	gopkg.in/yaml.v3 v3.0.1
-	modernc.org/sqlite v1.34.3
+	modernc.org/sqlite v1.34.5
 )

 require (
@@ -38,7 +38,6 @@ require (
 	github.com/gogs/chardet v0.0.0-20211120154057-b7413eaefb8f // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/gorilla/css v1.0.1 // indirect
-	github.com/hashicorp/golang-lru/v2 v2.0.7 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jaytaylor/html2text v0.0.0-20230321000545-74c2419ad056 // indirect
 	github.com/kr/pretty v0.3.0 // indirect
@@ -53,15 +52,12 @@ require (
 	github.com/ssor/bom v0.0.0-20170718123548-6386211fdfcf // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/vanng822/css v1.0.1 // indirect
-	golang.org/x/crypto v0.31.0 // indirect
-	golang.org/x/exp v0.0.0-20241217172543-b2144cdd0a67 // indirect
+	golang.org/x/crypto v0.32.0 // indirect
+	golang.org/x/exp v0.0.0-20250106191152-7588d65b2ba8 // indirect
 	golang.org/x/image v0.23.0 // indirect
-	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/sys v0.29.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
-	modernc.org/gc/v3 v3.0.0-20241213165251-3bc300f6d0c9 // indirect
-	modernc.org/libc v1.61.4 // indirect
-	modernc.org/mathutil v1.6.0 // indirect
-	modernc.org/memory v1.8.0 // indirect
-	modernc.org/strutil v1.2.0 // indirect
-	modernc.org/token v1.1.0 // indirect
+	modernc.org/libc v1.61.9 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.8.2 // indirect
 )
@@ -1,8 +1,8 @@
 github.com/GehirnInc/crypt v0.0.0-20230320061759-8cc1b52080c5 h1:IEjq88XO4PuBDcvmjQJcQGg+w+UaafSy8G5Kcb5tBhI=
 github.com/GehirnInc/crypt v0.0.0-20230320061759-8cc1b52080c5/go.mod h1:exZ0C/1emQJAw5tHOaUDyY1ycttqBAPcxuzf7QbY6ec=
 github.com/PuerkitoBio/goquery v1.9.2/go.mod h1:GHPCaP0ODyyxqcNoFGYlAprUFH81NuRPd0GX3Zu2Mvk=
-github.com/PuerkitoBio/goquery v1.10.0 h1:6fiXdLuUvYs2OJSvNRqlNPoBm6YABE226xrbavY5Wv4=
-github.com/PuerkitoBio/goquery v1.10.0/go.mod h1:TjZZl68Q3eGHNBA8CWaxAN7rOU1EbDz3CWuolcO5Yu4=
+github.com/PuerkitoBio/goquery v1.10.1 h1:Y8JGYUkXWTGRB6Ars3+j3kN0xg1YqqlwvdTV8WTFQcU=
+github.com/PuerkitoBio/goquery v1.10.1/go.mod h1:IYiHrOMps66ag56LEH7QYDDupKXyo5A8qrjIx3ZtujY=
 github.com/andybalholm/cascadia v1.3.2/go.mod h1:7gtRlve5FxPPgIgX36uWBX58OdBsSS6lUvCFb+h7KvU=
 github.com/andybalholm/cascadia v1.3.3 h1:AG2YHrzJIm4BZ19iwJ/DAua6Btl3IwJX+VI4kktS1LM=
 github.com/andybalholm/cascadia v1.3.3/go.mod h1:xNd9bqTn98Ln4DwST8/nG+H0yuB8Hmgu1YHNnWw0GeA=
@@ -37,8 +37,6 @@ github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
 github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
 github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
 github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
-github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
-github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jaytaylor/html2text v0.0.0-20230321000545-74c2419ad056 h1:iCHtR9CQyktQ5+f3dMVZfwD2KWJUgm7M0gdL9NGr8KA=
@@ -129,10 +127,11 @@ golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDf
 golang.org/x/crypto v0.22.0/go.mod h1:vr6Su+7cTlO45qkww3VDJlzDn0ctJvRgYbC2NvXHt+M=
 golang.org/x/crypto v0.23.0/go.mod h1:CKFgDieR+mRhux2Lsu27y0fO304Db0wZe70UKqHu0v8=
 golang.org/x/crypto v0.27.0/go.mod h1:1Xngt8kV6Dvbssa53Ziq6Eqn0HqbZi5Z6R0ZpwQzt70=
-golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
 golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
-golang.org/x/exp v0.0.0-20241217172543-b2144cdd0a67 h1:1UoZQm6f0P/ZO0w1Ri+f+ifG/gXhegadRdwBIXEFWDo=
-golang.org/x/exp v0.0.0-20241217172543-b2144cdd0a67/go.mod h1:qj5a5QZpwLU2NLQudwIN5koi3beDhSAlJwa67PuM98c=
+golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
+golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=
+golang.org/x/exp v0.0.0-20250106191152-7588d65b2ba8 h1:yqrTHse8TCMW1M1ZCP+VAR/l0kKxwaAIqN/il7x4voA=
+golang.org/x/exp v0.0.0-20250106191152-7588d65b2ba8/go.mod h1:tujkw807nyEEAamNbDrEGzRav+ilXA7PCRAd6xsmwiU=
 golang.org/x/image v0.23.0 h1:HseQ7c2OpPKTPVzNjG5fwJsOTCiiwS4QdsYi5XU6H68=
 golang.org/x/image v0.23.0/go.mod h1:wJJBTdLfCCf3tiHa1fNxpZmUI4mmoZvwMCPP0ddoNKY=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
@@ -153,8 +152,9 @@ golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
 golang.org/x/net v0.24.0/go.mod h1:2Q7sJY5mzlzWjKtYUEXSlBWCdyaioyXzRB2RtU8KVE8=
 golang.org/x/net v0.25.0/go.mod h1:JkAGAh7GEvH74S6FOH42FLoXpXbE/aqXSrIQjXgsiwM=
 golang.org/x/net v0.29.0/go.mod h1:gLkgy8jTGERgjzMic6DS9+SP0ajcu6Xu3Orq/SpETg0=
-golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
 golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
+golang.org/x/net v0.34.0 h1:Mb7Mrk043xzHgnRM88suvJFwzVrRfHEHJEl5/71CKw0=
+golang.org/x/net v0.34.0/go.mod h1:di0qlW3YNM5oh6GqDGQr92MyTozJPmybPK4Ev/Gm31k=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -181,8 +181,9 @@ golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
 golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/telemetry v0.0.0-20240228155512-f48c80bd79b2/go.mod h1:TeRTkGYfJXctD9OcfyVLyj2J3IxLnKwHJR8f4D8a3YE=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
@@ -206,16 +207,16 @@ golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/text v0.18.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
 golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
 golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
-golang.org/x/time v0.8.0 h1:9i3RxcPv3PZnitoVGMPDKZSq1xW1gK1Xy3ArNOGZfEg=
-golang.org/x/time v0.8.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
+golang.org/x/time v0.9.0 h1:EsRrnYcQiGH+5FfbgvV4AP7qEZstoyrHB0DzarOQ4ZY=
+golang.org/x/time v0.9.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=
 golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
-golang.org/x/tools v0.28.0 h1:WuB6qZ4RPCQo5aP3WdKZS7i595EdWqWR8vqJTlwTVK8=
-golang.org/x/tools v0.28.0/go.mod h1:dcIOrVd3mfQKTgrDVQHqCPMWy6lnhfhtX3hLXYVLfRw=
+golang.org/x/tools v0.29.0 h1:Xx0h3TtM9rzQpQuR4dKLrdglAmCEN5Oi+P74JdhdzXE=
+golang.org/x/tools v0.29.0/go.mod h1:KMQVMRsVxU6nHCFXrBPhDB8XncLNLM0lIy/F14RP588=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
@@ -225,29 +226,27 @@ gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-modernc.org/cc/v4 v4.23.1 h1:WqJoPL3x4cUufQVHkXpXX7ThFJ1C4ik80i2eXEXbhD8=
-modernc.org/cc/v4 v4.23.1/go.mod h1:HM7VJTZbUCR3rV8EYBi9wxnJ0ZBRiGE5OeGXNA0IsLQ=
-modernc.org/ccgo/v4 v4.23.1 h1:N49a7JiWGWV7lkPE4yYcvjkBGZQi93/JabRYjdWmJXc=
-modernc.org/ccgo/v4 v4.23.1/go.mod h1:JoIUegEIfutvoWV/BBfDFpPpfR2nc3U0jKucGcbmwDU=
+modernc.org/cc/v4 v4.24.4 h1:TFkx1s6dCkQpd6dKurBNmpo+G8Zl4Sq/ztJ+2+DEsh0=
+modernc.org/cc/v4 v4.24.4/go.mod h1:uVtb5OGqUKpoLWhqwNQo/8LwvoiEBLvZXIQ/SmO6mL0=
+modernc.org/ccgo/v4 v4.23.13 h1:PFiaemQwE/jdwi8XEHyEV+qYWoIuikLP3T4rvDeJb00=
+modernc.org/ccgo/v4 v4.23.13/go.mod h1:vdN4h2WR5aEoNondUx26K7G8X+nuBscYnAEWSRmN2/0=
 modernc.org/fileutil v1.3.0 h1:gQ5SIzK3H9kdfai/5x41oQiKValumqNTDXMvKo62HvE=
 modernc.org/fileutil v1.3.0/go.mod h1:XatxS8fZi3pS8/hKG2GH/ArUogfxjpEKs3Ku3aK4JyQ=
-modernc.org/gc/v2 v2.5.0 h1:bJ9ChznK1L1mUtAQtxi0wi5AtAs5jQuw4PrPHO5pb6M=
-modernc.org/gc/v2 v2.5.0/go.mod h1:wzN5dK1AzVGoH6XOzc3YZ+ey/jPgYHLuVckd62P0GYU=
-modernc.org/gc/v3 v3.0.0-20241213165251-3bc300f6d0c9 h1:ovz6yUKX71igz2yvk4NpiCL5fvdjZAI+DhuDEGx1xyU=
-modernc.org/gc/v3 v3.0.0-20241213165251-3bc300f6d0c9/go.mod h1:Qz0X07sNOR1jWYCrJMEnbW/X55x206Q7Vt4mz6/wHp4=
-modernc.org/libc v1.61.4 h1:wVyqEx6tlltte9lPTjq0kDAdtdM9c4JH8rU6M1ZVawA=
-modernc.org/libc v1.61.4/go.mod h1:VfXVuM/Shh5XsMNrh3C6OkfL78G3loa4ZC/Ljv9k7xc=
-modernc.org/mathutil v1.6.0 h1:fRe9+AmYlaej+64JsEEhoWuAYBkOtQiMEU7n/XgfYi4=
-modernc.org/mathutil v1.6.0/go.mod h1:Ui5Q9q1TR2gFm0AQRqQUaBWFLAhQpCwNcuhBOSedWPo=
-modernc.org/memory v1.8.0 h1:IqGTL6eFMaDZZhEWwcREgeMXYwmW83LYW8cROZYkg+E=
-modernc.org/memory v1.8.0/go.mod h1:XPZ936zp5OMKGWPqbD3JShgd/ZoQ7899TUuQqxY+peU=
-modernc.org/opt v0.1.3 h1:3XOZf2yznlhC+ibLltsDGzABUGVx8J6pnFMS3E4dcq4=
-modernc.org/opt v0.1.3/go.mod h1:WdSiB5evDcignE70guQKxYUl14mgWtbClRi5wmkkTX0=
-modernc.org/sortutil v1.2.0 h1:jQiD3PfS2REGJNzNCMMaLSp/wdMNieTbKX920Cqdgqc=
-modernc.org/sortutil v1.2.0/go.mod h1:TKU2s7kJMf1AE84OoiGppNHJwvB753OYfNl2WRb++Ss=
-modernc.org/sqlite v1.34.3 h1:494MIwJKBLd0tErBYkRar2HvEpy04Bl0ykPEm4XLhbo=
-modernc.org/sqlite v1.34.3/go.mod h1:dnR723UrTtjKpoHCAMN0Q/gZ9MT4r+iRvIBb9umWFkU=
-modernc.org/strutil v1.2.0 h1:agBi9dp1I+eOnxXeiZawM8F4LawKv4NzGWSaLfyeNZA=
-modernc.org/strutil v1.2.0/go.mod h1:/mdcBmfOibveCTBxUl5B5l6W+TTH1FXPLHZE6bTosX0=
+modernc.org/gc/v2 v2.6.1 h1:+Qf6xdG8l7B27TQ8D8lw/iFMUj1RXRBOuMUWziJOsk8=
+modernc.org/gc/v2 v2.6.1/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
+modernc.org/libc v1.61.9 h1:PLSBXVkifXGELtJ5BOnBUyAHr7lsatNwFU/RRo4kfJM=
+modernc.org/libc v1.61.9/go.mod h1:61xrnzk/aR8gr5bR7Uj/lLFLuXu2/zMpIjcry63Eumk=
+modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
+modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
+modernc.org/memory v1.8.2 h1:cL9L4bcoAObu4NkxOlKWBWtNHIsnnACGF/TbqQ6sbcI=
+modernc.org/memory v1.8.2/go.mod h1:ZbjSvMO5NQ1A2i3bWeDiVMxIorXwdClKE/0SZ+BMotU=
+modernc.org/opt v0.1.4 h1:2kNGMRiUjrp4LcaPuLY2PzUfqM/w9N23quVwhKt5Qm8=
+modernc.org/opt v0.1.4/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
+modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
+modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
+modernc.org/sqlite v1.34.5 h1:Bb6SR13/fjp15jt70CL4f18JIN7p7dnMExd+UFnF15g=
+modernc.org/sqlite v1.34.5/go.mod h1:YLuNmX9NKs8wRNK2ko1LW1NGYcc9FkBO69JOt1AR9JE=
+modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
+modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
 modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
 modernc.org/token v1.1.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=
@@ -0,0 +1,121 @@
+// Package chaos is used to simulate Chaos engineering (random failures) in the SMTPD server.
+// See https://en.wikipedia.org/wiki/Chaos_engineering
+// See https://mailpit.axllent.org/docs/integration/chaos/
+package chaos
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+	"strings"
+
+	"github.com/axllent/mailpit/internal/logger"
+)
+
+var (
+	// Enabled is a flag to enable or disable support for chaos
+	Enabled = false
+
+	// Config is the global Chaos configuration
+	Config = Triggers{
+		Sender:         Trigger{ErrorCode: 451, Probability: 0},
+		Recipient:      Trigger{ErrorCode: 451, Probability: 0},
+		Authentication: Trigger{ErrorCode: 535, Probability: 0},
+	}
+)
+
+// Triggers for the Chaos configuration
+//
+// swagger:model Triggers
+type Triggers struct {
+	// Sender trigger to fail on From, Sender
+	Sender Trigger
+	// Recipient trigger to fail on To, Cc, Bcc
+	Recipient Trigger
+	// Authentication trigger to fail while authenticating (auth must be configured)
+	Authentication Trigger
+}
+
+// Trigger for Chaos
+type Trigger struct {
+	// SMTP error code to return. The value must range from 400 to 599.
+	// required: true
+	// example: 451
+	ErrorCode int
+
+	// Probability (chance) of triggering the error. The value must range from 0 to 100.
+	// required: true
+	// example: 5
+	Probability int
+}
+
+// SetFromStruct will set a whole map of chaos configurations (ie: API)
+func SetFromStruct(c Triggers) error {
+	if c.Sender.ErrorCode == 0 {
+		c.Sender.ErrorCode = 451 // default
+	}
+
+	if c.Recipient.ErrorCode == 0 {
+		c.Recipient.ErrorCode = 451 // default
+	}
+
+	if c.Authentication.ErrorCode == 0 {
+		c.Authentication.ErrorCode = 535 // default
+	}
+
+	if err := Set("Sender", c.Sender.ErrorCode, c.Sender.Probability); err != nil {
+		return err
+	}
+	if err := Set("Recipient", c.Recipient.ErrorCode, c.Recipient.Probability); err != nil {
+		return err
+	}
+	if err := Set("Authentication", c.Authentication.ErrorCode, c.Authentication.Probability); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Set will set the chaos configuration for the given key (CLI & setMap())
+func Set(key string, errorCode int, probability int) error {
+	Enabled = true
+	if errorCode < 400 || errorCode > 599 {
+		return fmt.Errorf("error code must be between 400 and 599")
+	}
+
+	if probability > 100 || probability < 0 {
+		return fmt.Errorf("probability must be between 0 and 100")
+	}
+
+	key = strings.ToLower(key)
+
+	switch key {
+	case "sender":
+		Config.Sender = Trigger{ErrorCode: errorCode, Probability: probability}
+		logger.Log().Infof("[chaos] Sender to return %d error with %d%% probability", errorCode, probability)
+	case "recipient", "recipients":
+		Config.Recipient = Trigger{ErrorCode: errorCode, Probability: probability}
+		logger.Log().Infof("[chaos] Recipient to return %d error with %d%% probability", errorCode, probability)
+	case "auth", "authentication":
+		Config.Authentication = Trigger{ErrorCode: errorCode, Probability: probability}
+		logger.Log().Infof("[chaos] Authentication to return %d error with %d%% probability", errorCode, probability)
+	default:
+		return fmt.Errorf("unknown key %s", key)
+	}
+
+	return nil
+}
+
+// Trigger will return whether the Chaos rule is triggered based on the configuration
+// and a randomly-generated percentage value.
+func (c Trigger) Trigger() (bool, int) {
+	if !Enabled || c.Probability == 0 {
+		return false, 0
+	}
+
+	nBig, _ := rand.Int(rand.Reader, big.NewInt(100))
+
+	// rand.IntN(100) will return 0-99, whereas probability is 1-100,
+	// so value must be less than (not <=) to the probability to trigger
+	return int(nBig.Int64()) < c.Probability, c.ErrorCode
+}
@@ -0,0 +1,111 @@
+package smtpd
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net/smtp"
+	"strings"
+
+	"github.com/axllent/mailpit/config"
+	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/tools"
+)
+
+// Wrapper to forward messages if configured
+func autoForwardMessage(from string, data *[]byte) {
+	if config.SMTPForwardConfig.Host == "" {
+		return
+	}
+
+	if err := forward(from, *data); err != nil {
+		logger.Log().Errorf("[forward] error: %s", err.Error())
+	} else {
+		logger.Log().Debugf("[forward] message from %s to %s via %s:%d",
+			from, config.SMTPForwardConfig.To, config.SMTPForwardConfig.Host, config.SMTPForwardConfig.Port)
+	}
+}
+
+// Forward will connect to a pre-configured SMTP server and send a message to one or more recipients.
+func forward(from string, msg []byte) error {
+	addr := fmt.Sprintf("%s:%d", config.SMTPForwardConfig.Host, config.SMTPForwardConfig.Port)
+
+	c, err := smtp.Dial(addr)
+	if err != nil {
+		return fmt.Errorf("error connecting to %s: %s", addr, err.Error())
+	}
+
+	defer c.Close()
+
+	if config.SMTPForwardConfig.STARTTLS {
+		conf := &tls.Config{ServerName: config.SMTPForwardConfig.Host} // #nosec
+
+		conf.InsecureSkipVerify = config.SMTPForwardConfig.AllowInsecure
+
+		if err = c.StartTLS(conf); err != nil {
+			return fmt.Errorf("error creating StartTLS config: %s", err.Error())
+		}
+	}
+
+	auth := forwardAuthFromConfig()
+
+	if auth != nil {
+		if err = c.Auth(auth); err != nil {
+			return fmt.Errorf("error response to AUTH command: %s", err.Error())
+		}
+	}
+
+	if config.SMTPForwardConfig.OverrideFrom != "" {
+		msg, err = tools.OverrideFromHeader(msg, config.SMTPForwardConfig.OverrideFrom)
+		if err != nil {
+			return fmt.Errorf("error overriding From header: %s", err.Error())
+		}
+
+		from = config.SMTPForwardConfig.OverrideFrom
+	}
+
+	if err = c.Mail(from); err != nil {
+		return fmt.Errorf("error response to MAIL command: %s", err.Error())
+	}
+
+	to := strings.Split(config.SMTPForwardConfig.To, ",")
+
+	for _, addr := range to {
+		if err = c.Rcpt(addr); err != nil {
+			logger.Log().Warnf("error response to RCPT command for %s: %s", addr, err.Error())
+		}
+	}
+
+	w, err := c.Data()
+	if err != nil {
+		return fmt.Errorf("error response to DATA command: %s", err.Error())
+	}
+
+	if _, err := w.Write(msg); err != nil {
+		return fmt.Errorf("error sending message: %s", err.Error())
+	}
+
+	if err := w.Close(); err != nil {
+		return fmt.Errorf("error closing connection: %s", err.Error())
+	}
+
+	return c.Quit()
+}
+
+// Return the SMTP forwarding authentication based on config
+func forwardAuthFromConfig() smtp.Auth {
+	var a smtp.Auth
+
+	if config.SMTPForwardConfig.Auth == "plain" {
+		a = smtp.PlainAuth("", config.SMTPForwardConfig.Username, config.SMTPForwardConfig.Password, config.SMTPForwardConfig.Host)
+	}
+
+	if config.SMTPForwardConfig.Auth == "login" {
+		a = LoginAuth(config.SMTPForwardConfig.Username, config.SMTPForwardConfig.Password)
+	}
+
+	if config.SMTPForwardConfig.Auth == "cram-md5" {
+		a = smtp.CRAMMD5Auth(config.SMTPForwardConfig.Username, config.SMTPForwardConfig.Secret)
+	}
+
+	return a
+}
@@ -87,6 +87,9 @@ func SaveToDatabase(origin net.Addr, from string, to []string, data []byte) (str
 	// if enabled, this may conditionally relay the email through to the preconfigured smtp server
 	autoRelayMessage(from, to, &data)

+	// if enabled, this will forward a copy to preconfigured addresses
+	autoForwardMessage(from, &data)
+
 	// build array of all addresses in the header to compare to the []to array
 	emails, hasBccHeader := scanAddressesInHeader(msg.Header)

@@ -9,14 +9,16 @@ import (

 	"github.com/axllent/mailpit/config"
 	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/tools"
 )

+// Wrapper to auto relay messages if configured
 func autoRelayMessage(from string, to []string, data *[]byte) {
 	if config.SMTPRelayConfig.BlockedRecipientsRegexp != nil {
 		filteredTo := []string{}
 		for _, address := range to {
 			if config.SMTPRelayConfig.BlockedRecipientsRegexp.MatchString(address) {
-				logger.Log().Debugf("[smtp] ignoring auto-relay to %s: found in blocklist", address)
+				logger.Log().Debugf("[relay] ignoring auto-relay to %s: found in blocklist", address)
 				continue
 			}

@@ -31,9 +33,9 @@ func autoRelayMessage(from string, to []string, data *[]byte) {

 	if config.SMTPRelayAll {
 		if err := Relay(from, to, *data); err != nil {
-			logger.Log().Errorf("[smtp] error relaying message: %s", err.Error())
+			logger.Log().Errorf("[relay] error: %s", err.Error())
 		} else {
-			logger.Log().Debugf("[smtp] auto-relay message to %s from %s via %s:%d",
+			logger.Log().Debugf("[relay] sent message to %s from %s via %s:%d",
 				strings.Join(to, ", "), from, config.SMTPRelayConfig.Host, config.SMTPRelayConfig.Port)
 		}
 	} else if config.SMTPRelayMatchingRegexp != nil {
@@ -49,9 +51,9 @@ func autoRelayMessage(from string, to []string, data *[]byte) {
 		}

 		if err := Relay(from, filtered, *data); err != nil {
-			logger.Log().Errorf("[smtp] error relaying message: %s", err.Error())
+			logger.Log().Errorf("[relay] error: %s", err.Error())
 		} else {
-			logger.Log().Debugf("[smtp] auto-relay message to %s from %s via %s:%d",
+			logger.Log().Debugf("[relay] auto-relay message to %s from %s via %s:%d",
 				strings.Join(filtered, ", "), from, config.SMTPRelayConfig.Host, config.SMTPRelayConfig.Port)
 		}
 	}
@@ -86,6 +88,15 @@ func Relay(from string, to []string, msg []byte) error {
 		}
 	}

+	if config.SMTPRelayConfig.OverrideFrom != "" {
+		msg, err = tools.OverrideFromHeader(msg, config.SMTPRelayConfig.OverrideFrom)
+		if err != nil {
+			return fmt.Errorf("error overriding From header: %s", err.Error())
+		}
+
+		from = config.SMTPRelayConfig.OverrideFrom
+	}
+
 	if err = c.Mail(from); err != nil {
 		return fmt.Errorf("error response to MAIL command: %s", err.Error())
 	}
@@ -1,7 +1,7 @@
 // Package smtpd implements a basic SMTP server.
 //
 // This is a modified version of https://github.com/mhale/smtpd to
-// add optional support for unix sockets.
+// add support for unix sockets and Mailpit Chaos.
 package smtpd

 import (
@@ -22,6 +22,8 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
+
+	"github.com/axllent/mailpit/internal/smtpd/chaos"
 )

 var (
@@ -390,7 +392,7 @@ loop:
 			buffer.Reset()
 		case "EHLO":
 			s.remoteName = args
-			s.writef(s.makeEHLOResponse())
+			s.writef("%s", s.makeEHLOResponse())

 			// RFC 2821 section 4.1.4 specifies that EHLO has the same effect as RSET.
 			from = ""
@@ -411,6 +413,12 @@ loop:
 			if match == nil {
 				s.writef("501 5.5.4 Syntax error in parameters or arguments (invalid FROM parameter)")
 			} else {
+				// Mailpit Chaos
+				if fail, code := chaos.Config.Sender.Trigger(); fail {
+					s.writef("%d Chaos sender error", code)
+					break
+				}
+
 				// Validate the SIZE parameter if one was sent.
 				if len(match[2]) > 0 { // A parameter is present
 					sizeMatch := mailFromSizeRE.FindStringSubmatch(match[3])
@@ -426,7 +434,7 @@ loop:
 							s.writef("501 5.5.4 Syntax error in parameters or arguments (invalid SIZE parameter)")
 						} else if s.srv.MaxSize > 0 && size > s.srv.MaxSize { // SIZE above maximum size, if set
 							err = maxSizeExceeded(s.srv.MaxSize)
-							s.writef(err.Error())
+							s.writef("%s", err.Error())
 						} else { // SIZE ok
 							from = match[1]
 							gotFrom = true
@@ -439,6 +447,7 @@ loop:
 					s.writef("250 2.1.0 Ok")
 				}
 			}
+
 			to = nil
 			buffer.Reset()
 		case "RCPT":
@@ -459,10 +468,17 @@ loop:
 			if match == nil {
 				s.writef("501 5.5.4 Syntax error in parameters or arguments (invalid TO parameter)")
 			} else {
+				// Mailpit Chaos
+				if fail, code := chaos.Config.Recipient.Trigger(); fail {
+					s.writef("%d Chaos recipient error", code)
+					break
+				}
+
 				// RFC 5321 specifies support for minimum of 100 recipients is required.
 				if s.srv.MaxRecipients == 0 {
 					s.srv.MaxRecipients = 100
 				}
+
 				if len(to) == s.srv.MaxRecipients {
 					s.writef("452 4.5.3 Too many recipients")
 				} else {
@@ -507,7 +523,7 @@ loop:
 					}
 					break loop
 				case maxSizeExceededError:
-					s.writef(err.Error())
+					s.writef("%s", err.Error())
 					continue
 				default:
 					s.writef("451 4.3.0 Requested action aborted: local error in processing")
@@ -526,7 +542,7 @@ loop:
 				if err != nil {
 					checkErrFormat := regexp.MustCompile(`^([2-5][0-9]{2})[\s\-](.+)$`)
 					if checkErrFormat.MatchString(err.Error()) {
-						s.writef(err.Error())
+						s.writef("%s", err.Error())
 					} else {
 						s.writef("451 4.3.5 Unable to process mail")
 					}
@@ -538,7 +554,7 @@ loop:
 				if err != nil {
 					checkErrFormat := regexp.MustCompile(`^([2-5][0-9]{2})[\s\-](.+)$`)
 					if checkErrFormat.MatchString(err.Error()) {
-						s.writef(err.Error())
+						s.writef("%s", err.Error())
 					} else {
 						s.writef("451 4.3.5 Unable to process mail")
 					}
@@ -546,7 +562,7 @@ loop:
 				}

 				if msgID != "" {
-					s.writef("250 2.0.0 Ok: queued as " + msgID)
+					s.writef("250 2.0.0 Ok: queued as %s", msgID)
 				} else {
 					s.writef("250 2.0.0 Ok: queued")
 				}
@@ -685,6 +701,12 @@ loop:
 				break
 			}

+			// Mailpit Chaos
+			if fail, code := chaos.Config.Authentication.Trigger(); fail {
+				s.writef("%d Chaos authentication error", code)
+				break
+			}
+
 			// RFC 4954 also specifies that ESMTP code 5.5.4 ("Invalid command arguments") should be returned
 			// when attempting to use an unsupported authentication type.
 			// Many servers return 5.7.4 ("Security features not supported") instead.
@@ -703,7 +725,7 @@ loop:
 					break loop
 				}

-				s.writef(err.Error())
+				s.writef("%s", err.Error())
 				break
 			}

@@ -726,7 +748,7 @@ func (s *session) writef(format string, args ...interface{}) {
 	}

 	line := fmt.Sprintf(format, args...)
-	fmt.Fprintf(s.bw, line+"\r\n")
+	fmt.Fprintf(s.bw, "%s\r\n", line)
 	_ = s.bw.Flush()

 	if Debug {
@@ -869,7 +891,7 @@ func (s *session) handleAuthLogin(arg string) (bool, error) {
 	var err error

 	if arg == "" {
-		s.writef("334 " + base64.StdEncoding.EncodeToString([]byte("Username:")))
+		s.writef("334 %s", base64.StdEncoding.EncodeToString([]byte("Username:")))
 		arg, err = s.readLine()
 		if err != nil {
 			return false, err
@@ -881,7 +903,7 @@ func (s *session) handleAuthLogin(arg string) (bool, error) {
 		return false, errors.New("501 5.5.2 Syntax error (unable to decode)")
 	}

-	s.writef("334 " + base64.StdEncoding.EncodeToString([]byte("Password:")))
+	s.writef("334 %s", base64.StdEncoding.EncodeToString([]byte("Password:")))
 	line, err := s.readLine()
 	if err != nil {
 		return false, err
@@ -929,7 +951,7 @@ func (s *session) handleAuthPlain(arg string) (bool, error) {
 func (s *session) handleAuthCramMD5() (bool, error) {
 	shared := "<" + strconv.Itoa(os.Getpid()) + "." + strconv.Itoa(time.Now().Nanosecond()) + "@" + s.srv.Hostname + ">"

-	s.writef("334 " + base64.StdEncoding.EncodeToString([]byte(shared)))
+	s.writef("334 %s", base64.StdEncoding.EncodeToString([]byte(shared)))

 	data, err := s.readLine()
 	if err != nil {
@@ -535,7 +535,7 @@ func TestCmdSTARTTLSRequired(t *testing.T) {
 }

 func TestMakeHeaders(t *testing.T) {
-	now := time.Now().Format("Mon, _2 Jan 2006 15:04:05 -0700 (MST)")
+	now := time.Now().Format("Mon, 2 Jan 2006 15:04:05 -0700 (MST)")
 	valid := "Received: from clientName (clientHost [clientIP])\r\n" +
 		"        by serverName (smtpd) with SMTP\r\n" +
 		"        for <recipient@example.com>; " +
@@ -6,6 +6,7 @@ import (
 	"bytes"
 	"net/mail"
 	"regexp"
+	"strings"

 	"github.com/axllent/mailpit/internal/logger"
 )
@@ -48,7 +49,7 @@ func RemoveMessageHeaders(msg []byte, headers []string) ([]byte, error) {
 			}

 			if len(hdr) > 0 {
-				logger.Log().Debugf("[release] removed %s header", hdr)
+				logger.Log().Debugf("[relay] removed %s header", hdr)
 				msg = bytes.Replace(msg, hdr, []byte(""), 1)
 			}
 		}
@@ -90,10 +91,70 @@ func UpdateMessageHeader(msg []byte, header, value string) ([]byte, error) {
 		}

 		if len(hdr) > 0 {
-			logger.Log().Debugf("[release] replaced %s header", hdr)
+			logger.Log().Debugf("[relay] replaced %s header", hdr)
 			msg = bytes.Replace(msg, hdr, []byte(header+": "+value+"\r\n"), 1)
 		}
 	}

 	return msg, nil
 }
+
+// OverrideFromHeader scans a message for the From header and replaces it with a different email address.
+func OverrideFromHeader(msg []byte, address string) ([]byte, error) {
+	reader := bytes.NewReader(msg)
+	m, err := mail.ReadMessage(reader)
+	if err != nil {
+		return nil, err
+	}
+
+	if m.Header.Get("From") != "" {
+		reBlank := regexp.MustCompile(`^\s+`)
+		reHdr := regexp.MustCompile(`(?i)^` + regexp.QuoteMeta("From:"))
+
+		scanner := bufio.NewScanner(bytes.NewReader(msg))
+		found := false
+		hdr := []byte("")
+		for scanner.Scan() {
+			line := scanner.Bytes()
+			if !found && reHdr.Match(line) {
+				// add the first line starting with <header>:
+				hdr = append(hdr, line...)
+				hdr = append(hdr, []byte("\r\n")...)
+				found = true
+			} else if found && reBlank.Match(line) {
+				// add any following lines starting with a whitespace (tab or space)
+				hdr = append(hdr, line...)
+				hdr = append(hdr, []byte("\r\n")...)
+			} else if found {
+				// stop scanning, we have the full <header>
+				break
+			}
+		}
+
+		if len(hdr) > 0 {
+			originalFrom := strings.TrimRight(string(hdr[5:]), "\r\n")
+
+			from, err := mail.ParseAddress(originalFrom)
+			if err != nil {
+				// error parsing the from address, so just replace the whole line
+				msg = bytes.Replace(msg, hdr, []byte("From: "+address+"\r\n"), 1)
+			} else {
+				originalFrom = from.Address
+				// replace the from email, but keep the original name
+				from.Address = address
+				msg = bytes.Replace(msg, hdr, []byte("From: "+from.String()+"\r\n"), 1)
+			}
+
+			// insert the original From header as X-Original-From
+			msg = append([]byte("X-Original-From: "+originalFrom+"\r\n"), msg...)
+
+			logger.Log().Debugf("[relay] Replaced From email address with %s", address)
+		}
+	} else {
+		// no From header, so add one
+		msg = append([]byte("From: "+address+"\r\n"), msg...)
+		logger.Log().Debugf("[relay] Added From email: %s", address)
+	}
+
+	return msg, nil
+}
@@ -6,7 +6,7 @@
    "build": "MINIFY=true node esbuild.config.mjs",
    "watch": "WATCH=true node esbuild.config.mjs",
    "package": "MINIFY=true node esbuild.config.mjs",
-    "update-caniemail": "wget -O utils/html-check/caniemail-data.json https://www.caniemail.com/api/data.json"
+    "update-caniemail": "wget -O internal/htmlcheck/caniemail-data.json https://www.caniemail.com/api/data.json"
  },
  "dependencies": {
    "axios": "^1.2.1",
@@ -6,6 +6,7 @@ import (
 	"net/http"

 	"github.com/axllent/mailpit/config"
+	"github.com/axllent/mailpit/internal/smtpd/chaos"
 	"github.com/axllent/mailpit/internal/stats"
 )

@@ -59,6 +60,8 @@ type webUIConfiguration struct {
 		AllowedRecipients string
 		// Block relaying to these recipients (regex)
 		BlockedRecipients string
+		// Overrides the "From" address for all relayed messages
+		OverrideFrom string
 		// DEPRECATED 2024/03/12
 		// swagger:ignore
 		RecipientAllowlist string
@@ -67,6 +70,9 @@ type webUIConfiguration struct {
 	// Whether SpamAssassin is enabled
 	SpamAssassin bool

+	// Whether Chaos support is enabled at runtime
+	ChaosEnabled bool
+
 	// Whether messages with duplicate IDs are ignored
 	DuplicatesIgnored bool
 }
@@ -107,11 +113,13 @@ func WebUIConfig(w http.ResponseWriter, _ *http.Request) {
 		conf.MessageRelay.ReturnPath = config.SMTPRelayConfig.ReturnPath
 		conf.MessageRelay.AllowedRecipients = config.SMTPRelayConfig.AllowedRecipients
 		conf.MessageRelay.BlockedRecipients = config.SMTPRelayConfig.BlockedRecipients
+		conf.MessageRelay.OverrideFrom = config.SMTPRelayConfig.OverrideFrom
 		// DEPRECATED 2024/03/12
 		conf.MessageRelay.RecipientAllowlist = config.SMTPRelayConfig.AllowedRecipients
 	}

 	conf.SpamAssassin = config.EnableSpamAssassin != ""
+	conf.ChaosEnabled = chaos.Enabled
 	conf.DuplicatesIgnored = config.IgnoreDuplicateIDs

 	w.Header().Add("Content-Type", "application/json")
@@ -0,0 +1,112 @@
+package apiv1
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/axllent/mailpit/internal/smtpd/chaos"
+)
+
+// ChaosTriggers is the Chaos configuration
+//
+// swagger:model Triggers
+type ChaosTriggers chaos.Triggers
+
+// Response for the Chaos triggers configuration
+// swagger:response ChaosResponse
+type chaosResponse struct {
+	// The current Chaos triggers
+	//
+	// in: body
+	Body ChaosTriggers
+}
+
+// GetChaos returns the current Chaos triggers
+func GetChaos(w http.ResponseWriter, _ *http.Request) {
+	// swagger:route GET /api/v1/chaos testing getChaos
+	//
+	// # Get Chaos triggers
+	//
+	// Returns the current Chaos triggers configuration.
+	// This API route will return an error if Chaos is not enabled at runtime.
+	//
+	//	Produces:
+	//	  - application/json
+	//
+	//	Schemes: http, https
+	//
+	//	Responses:
+	//	  200: ChaosResponse
+	//	  400: ErrorResponse
+
+	if !chaos.Enabled {
+		httpError(w, "Chaos is not enabled")
+		return
+	}
+
+	conf := chaos.Config
+
+	w.Header().Add("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(conf); err != nil {
+		httpError(w, err.Error())
+	}
+}
+
+// swagger:parameters setChaosParams
+type setChaosParams struct {
+	// in: body
+	Body ChaosTriggers
+}
+
+// SetChaos sets the Chaos configuration.
+func SetChaos(w http.ResponseWriter, r *http.Request) {
+	// swagger:route PUT /api/v1/chaos testing setChaosParams
+	//
+	// # Set Chaos triggers
+	//
+	// Set the Chaos triggers configuration and return the updated values.
+	// This API route will return an error if Chaos is not enabled at runtime.
+	//
+	// If any triggers are omitted from the request, then those are reset to their
+	// default values with a 0% probability (ie: disabled).
+	// Setting a blank `{}` will reset all triggers to their default values.
+	//
+	//	Consumes:
+	//	  - application/json
+	//
+	//	Produces:
+	//	  - application/json
+	//
+	//	Schemes: http, https
+	//
+	//	Responses:
+	//	  200: ChaosResponse
+	//	  400: ErrorResponse
+
+	if !chaos.Enabled {
+		httpError(w, "Chaos is not enabled")
+		return
+	}
+
+	data := chaos.Triggers{}
+
+	decoder := json.NewDecoder(r.Body)
+
+	err := decoder.Decode(&data)
+	if err != nil {
+		httpError(w, err.Error())
+		return
+	}
+
+	if err := chaos.SetFromStruct(data); err != nil {
+		httpError(w, err.Error())
+		return
+	}
+
+	conf := chaos.Config
+
+	w.Header().Add("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(conf); err != nil {
+		httpError(w, err.Error())
+	}
+}
@@ -30,7 +30,7 @@ type HTMLCheckResponse = htmlcheck.Response

 // HTMLCheck returns a summary of the HTML client support
 func HTMLCheck(w http.ResponseWriter, r *http.Request) {
-	// swagger:route GET /api/v1/message/{ID}/html-check Other HTMLCheckParams
+	// swagger:route GET /api/v1/message/{ID}/html-check other HTMLCheckParams
 	//
 	// # HTML check
 	//
@@ -114,7 +114,7 @@ type LinkCheckResponse = linkcheck.Response

 // LinkCheck returns a summary of links in the email
 func LinkCheck(w http.ResponseWriter, r *http.Request) {
-	// swagger:route GET /api/v1/message/{ID}/link-check Other LinkCheckParams
+	// swagger:route GET /api/v1/message/{ID}/link-check other LinkCheckParams
 	//
 	// # Link check
 	//
@@ -184,7 +184,7 @@ type SpamAssassinResponse = spamassassin.Result

 // SpamAssassinCheck returns a summary of SpamAssassin results (if enabled)
 func SpamAssassinCheck(w http.ResponseWriter, r *http.Request) {
-	// swagger:route GET /api/v1/message/{ID}/sa-check Other SpamAssassinCheckParams
+	// swagger:route GET /api/v1/message/{ID}/sa-check other SpamAssassinCheckParams
 	//
 	// # SpamAssassin check
 	//
@@ -183,6 +183,10 @@ func apiRoutes() *mux.Router {
 	r.HandleFunc(config.Webroot+"api/v1/webui", middleWareFunc(apiv1.WebUIConfig)).Methods("GET")
 	r.HandleFunc(config.Webroot+"api/v1/swagger.json", middleWareFunc(swaggerBasePath)).Methods("GET")

+	// Chaos
+	r.HandleFunc(config.Webroot+"api/v1/chaos", middleWareFunc(apiv1.GetChaos)).Methods("GET")
+	r.HandleFunc(config.Webroot+"api/v1/chaos", middleWareFunc(apiv1.SetChaos)).Methods("PUT")
+
 	// web UI websocket
 	r.HandleFunc(config.Webroot+"api/events", apiWebsocket).Methods("GET")

@@ -12,6 +12,8 @@ export default {
 			mailbox,
 			theme: localStorage.getItem('theme') ? localStorage.getItem('theme') : 'auto',
 			timezones,
+			chaosConfig: false,
+			chaosUpdated: false,
 		}
 	},

@@ -23,6 +25,13 @@ export default {
 				localStorage.setItem('theme', v)
 			}
 			this.setTheme()
+		},
+
+		chaosConfig: {
+			handler() {
+				this.chaosUpdated = true
+			},
+			deep: true
 		}
 	},

@@ -44,6 +53,24 @@ export default {
 				document.documentElement.setAttribute('data-bs-theme', this.theme)
 			}
 		},
+
+		loadChaos() {
+			this.get(this.resolve('/api/v1/chaos'), null, (response) => {
+				this.chaosConfig = response.data
+				this.$nextTick(() => {
+					this.chaosUpdated = false
+				})
+			})
+		},
+
+		saveChaos() {
+			this.put(this.resolve('/api/v1/chaos'), this.chaosConfig, (response) => {
+				this.chaosConfig = response.data
+				this.$nextTick(() => {
+					this.chaosUpdated = false
+				})
+			})
+		}
 	}
 }
 </script>
@@ -54,64 +81,189 @@ export default {
 		<div class="modal-dialog modal-lg">
 			<div class="modal-content">
 				<div class="modal-header">
-					<h5 class="modal-title" id="SettingsModalLabel">Mailpit UI settings</h5>
+					<h5 class="modal-title" id="SettingsModalLabel">Mailpit settings</h5>
 					<button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
 				</div>
 				<div class="modal-body">
-					<div class="mb-3">
-						<label for="theme" class="form-label">Mailpit theme</label>
-						<select class="form-select" v-model="theme" id="theme">
-							<option value="auto">Auto (detect from browser)</option>
-							<option value="light">Light theme</option>
-							<option value="dark">Dark theme</option>
-						</select>
-					</div>
-					<div class="mb-3">
-						<label for="timezone" class="form-label">Timezone (for date searches)</label>
-						<select class="form-select tz" v-model="mailbox.timeZone" id="timezone" data-allow-same="true">
-							<option disabled hidden value="">Select a timezone...</option>
-							<option v-for="t in timezones" :value="t.tzCode">{{ t.label }}</option>
-						</select>
-					</div>
-					<div class="mb-3">
-						<div class="form-check form-switch">
-							<input class="form-check-input" type="checkbox" role="switch" id="tagColors"
-								v-model="mailbox.showTagColors">
-							<label class="form-check-label" for="tagColors">
-								Use auto-generated tag colors
-							</label>
+					<ul class="nav nav-tabs" id="myTab" role="tablist" v-if="mailbox.uiConfig.ChaosEnabled">
+						<li class="nav-item" role="presentation">
+							<button class="nav-link active" id="ui-tab" data-bs-toggle="tab"
+								data-bs-target="#ui-tab-pane" type="button" role="tab" aria-controls="ui-tab-pane"
+								aria-selected="true">Web UI</button>
+						</li>
+						<li class="nav-item" role="presentation">
+							<button class="nav-link" id="chaos-tab" data-bs-toggle="tab"
+								data-bs-target="#chaos-tab-pane" type="button" role="tab" aria-controls="chaos-tab-pane"
+								aria-selected="false" @click="loadChaos">Chaos</button>
+						</li>
+					</ul>
+
+					<div class="tab-content">
+						<div class="tab-pane fade show active" id="ui-tab-pane" role="tabpanel" aria-labelledby="ui-tab"
+							tabindex="0">
+							<div class="my-3">
+								<label for="theme" class="form-label">Mailpit theme</label>
+								<select class="form-select" v-model="theme" id="theme">
+									<option value="auto">Auto (detect from browser)</option>
+									<option value="light">Light theme</option>
+									<option value="dark">Dark theme</option>
+								</select>
+							</div>
+							<div class="mb-3">
+								<label for="timezone" class="form-label">Timezone (for date searches)</label>
+								<select class="form-select tz" v-model="mailbox.timeZone" id="timezone"
+									data-allow-same="true">
+									<option disabled hidden value="">Select a timezone...</option>
+									<option v-for="t in timezones" :value="t.tzCode">{{ t.label }}</option>
+								</select>
+							</div>
+							<div class="mb-3">
+								<div class="form-check form-switch">
+									<input class="form-check-input" type="checkbox" role="switch" id="tagColors"
+										v-model="mailbox.showTagColors">
+									<label class="form-check-label" for="tagColors">
+										Use auto-generated tag colors
+									</label>
+								</div>
+							</div>
+							<div class="mb-3">
+								<div class="form-check form-switch">
+									<input class="form-check-input" type="checkbox" role="switch" id="htmlCheck"
+										v-model="mailbox.showHTMLCheck">
+									<label class="form-check-label" for="htmlCheck">
+										Show HTML check message tab
+									</label>
+								</div>
+							</div>
+							<div class="mb-3">
+								<div class="form-check form-switch">
+									<input class="form-check-input" type="checkbox" role="switch" id="linkCheck"
+										v-model="mailbox.showLinkCheck">
+									<label class="form-check-label" for="linkCheck">
+										Show link check message tab
+									</label>
+								</div>
+							</div>
+							<div class="mb-3" v-if="mailbox.uiConfig.SpamAssassin">
+								<div class="form-check form-switch">
+									<input class="form-check-input" type="checkbox" role="switch" id="spamCheck"
+										v-model="mailbox.showSpamCheck">
+									<label class="form-check-label" for="spamCheck">
+										Show spam check message tab
+									</label>
+								</div>
+							</div>
 						</div>
-					</div>
-					<div class="mb-3">
-						<div class="form-check form-switch">
-							<input class="form-check-input" type="checkbox" role="switch" id="htmlCheck"
-								v-model="mailbox.showHTMLCheck">
-							<label class="form-check-label" for="htmlCheck">
-								Show HTML check message tab
-							</label>
+
+						<div class="tab-pane fade" id="chaos-tab-pane" role="tabpanel" aria-labelledby="chaos-tab"
+							tabindex="0" v-if="mailbox.uiConfig.ChaosEnabled">
+							<p class="my-3">
+								<b>Chaos</b> allows you to set random SMTP failures and response codes at various
+								stages in a SMTP transaction to test application resilience
+								(<a href="https://mailpit.axllent.org/docs/integration/chaos/" target="_blank">
+									see documentation
+								</a>).
+							</p>
+
+							<ul>
+								<li>
+									<code>Response code</code> is the SMTP error code returned by the server if this
+									error is triggered. Error codes must range between 400 and 599.
+								</li>
+								<li>
+									<code>Error probability</code> is the % chance that the error will occur per message
+									delivery, where <code>0</code>(%) is disabled and <code>100</code>(%) wil always
+									trigger. A probability of <code>50</code> will trigger on approximately 50% of
+									messages received.
+								</li>
+							</ul>
+
+							<template v-if="chaosConfig">
+								<div class="mt-4 mb-4" :class="chaosUpdated ? 'was-validated' : ''">
+									<div class="mb-4">
+										<label>Trigger: <code>Sender</code></label>
+										<div class="form-text">
+											Trigger an error response based on the sender (From / Sender).
+										</div>
+										<div class="row mt-1">
+											<div class="col">
+												<label class="form-label">
+													Response code
+												</label>
+												<input type="number" class="form-control"
+													v-model.number="chaosConfig.Sender.ErrorCode" min="400" max="599"
+													required>
+											</div>
+											<div class="col">
+												<label class="form-label">
+													Error probability ({{ chaosConfig.Sender.Probability }}%)
+												</label>
+												<input type="range" class="form-range mt-1" min="0" max="100"
+													v-model.number="chaosConfig.Sender.Probability">
+											</div>
+										</div>
+									</div>
+
+									<div class="mb-4">
+										<label>Trigger: <code>Recipient</code></label>
+										<div class="form-text">
+											Trigger an error response based on the recipients (To, Cc, Bcc).
+										</div>
+										<div class="row mt-1">
+											<div class="col">
+												<label class="form-label">
+													Response code
+												</label>
+												<input type="number" class="form-control"
+													v-model.number="chaosConfig.Recipient.ErrorCode" min="400" max="599"
+													required>
+											</div>
+											<div class="col">
+												<label class="form-label">
+													Error probability ({{ chaosConfig.Recipient.Probability }}%)
+												</label>
+												<input type="range" class="form-range mt-1" min="0" max="100"
+													v-model.number="chaosConfig.Recipient.Probability">
+											</div>
+										</div>
+									</div>
+
+									<div class="mb-4">
+										<label>Trigger: <code>Authentication</code></label>
+										<div class="form-text">
+											Trigger an authentication error response.
+											Note that SMTP authentication must be configured too.
+										</div>
+										<div class="row mt-1">
+											<div class="col">
+												<label class="form-label">
+													Response code
+												</label>
+												<input type="number" class="form-control"
+													v-model.number="chaosConfig.Authentication.ErrorCode" min="400"
+													max="599" required>
+											</div>
+											<div class="col">
+												<label class="form-label">
+													Error probability ({{ chaosConfig.Authentication.Probability }}%)
+												</label>
+												<input type="range" class="form-range mt-1" min="0" max="100"
+													v-model.number="chaosConfig.Authentication.Probability">
+											</div>
+										</div>
+									</div>
+								</div>
+
+								<div v-if="chaosUpdated" class="mb-3 text-center">
+									<button class="btn btn-success" @click="saveChaos">Update Chaos</button>
+								</div>
+							</template>
 						</div>
+
 					</div>
-					<div class="mb-3">
-						<div class="form-check form-switch">
-							<input class="form-check-input" type="checkbox" role="switch" id="linkCheck"
-								v-model="mailbox.showLinkCheck">
-							<label class="form-check-label" for="linkCheck">
-								Show link check message tab
-							</label>
-						</div>
+					<div class="modal-footer">
+						<button type="button" class="btn btn-outline-secondary" data-bs-dismiss="modal">Close</button>
 					</div>
-					<div class="mb-3" v-if="mailbox.uiConfig.SpamAssassin">
-						<div class="form-check form-switch">
-							<input class="form-check-input" type="checkbox" role="switch" id="spamCheck"
-								v-model="mailbox.showSpamCheck">
-							<label class="form-check-label" for="spamCheck">
-								Show spam check message tab
-							</label>
-						</div>
-					</div>
-				</div>
-				<div class="modal-footer">
-					<button type="button" class="btn btn-outline-secondary" data-bs-dismiss="modal">Close</button>
 				</div>
 			</div>
 		</div>
@@ -86,7 +86,10 @@ export default {
 					<div class="row">
 						<label class="col-sm-2 col-form-label text-body-secondary">From</label>
 						<div class="col-sm-10">
-							<input type="text" aria-label="From address" readonly class="form-control-plaintext"
+							<input v-if="mailbox.uiConfig.MessageRelay.OverrideFrom != ''" type="text"
+								aria-label="From address" readonly class="form-control-plaintext"
+								:value="mailbox.uiConfig.MessageRelay.OverrideFrom">
+							<input v-else type="text" aria-label="From address" readonly class="form-control-plaintext"
 								:value="message.From ? message.From.Address : ''">
 						</div>
 					</div>
@@ -122,51 +125,39 @@ export default {
 									Delete the message after release
 								</label>
 							</div>
-
 						</div>
 					</div>
-					
+
 					<h6>Notes</h6>
 					<ul>
 						<li v-if="mailbox.uiConfig.MessageRelay.AllowedRecipients != ''" class="form-text">
-							A recipient <b>allowlist</b> has been configured. Any mail address not matching the following will be rejected:
+							A recipient <b>allowlist</b> has been configured. Any mail address not matching the
+							following will be rejected:
 							<code>{{ mailbox.uiConfig.MessageRelay.AllowedRecipients }}</code>
 						</li>
 						<li v-if="mailbox.uiConfig.MessageRelay.BlockedRecipients != ''" class="form-text">
-							A recipient <b>blocklist</b> has been configured. Any mail address matching the following will be rejected:
+							A recipient <b>blocklist</b> has been configured. Any mail address matching the following
+							will be rejected:
 							<code>{{ mailbox.uiConfig.MessageRelay.BlockedRecipients }}</code>
 						</li>
 						<li class="form-text">
 							For testing purposes, a new unique <code>Message-Id</code> will be generated on send.
 						</li>
+						<li v-if="mailbox.uiConfig.MessageRelay.OverrideFrom != ''" class="form-text">
+							The <code>From</code> email address has been overridden by the relay configuration to
+							<code>{{ mailbox.uiConfig.MessageRelay.OverrideFrom }}</code>.
+						</li>
 						<li class="form-text">
 							SMTP delivery failures will bounce back to
 							<code v-if="mailbox.uiConfig.MessageRelay.ReturnPath != ''">
 								{{ mailbox.uiConfig.MessageRelay.ReturnPath }}
 							</code>
+							<code v-else-if="mailbox.uiConfig.MessageRelay.OverrideFrom != ''">
+								{{ mailbox.uiConfig.MessageRelay.OverrideFrom }}
+							</code>
 							<code v-else>{{ message.ReturnPath }}</code>.
 						</li>
 					</ul>
-
-					<!-- <div class="form-text text-center" v-if="mailbox.uiConfig.MessageRelay.AllowedRecipients != ''">
-						Note: A recipient allowlist has been configured. Any mail address not matching it will be
-						rejected.<br class="d-none d-md-inline">
-						Allowed recipients: <b>{{ mailbox.uiConfig.MessageRelay.AllowedRecipients }}</b>
-					</div>
-					<div class="form-text text-center" v-if="mailbox.uiConfig.MessageRelay.BlockedRecipients != ''">
-						Note: A recipient blocklist has been configured. Any mail address matching it will be
-						rejected.<br class="d-none d-md-inline">
-						Blocked recipients: <b>{{ mailbox.uiConfig.MessageRelay.BlockedRecipients }}</b>
-					</div>
-					<div class="form-text text-center">
-						Note: For testing purposes, a unique Message-Id will be generated on send.
-						<br class="d-none d-md-inline">
-						SMTP delivery failures will bounce back to
-						<b v-if="mailbox.uiConfig.MessageRelay.ReturnPath != ''">
-							{{ mailbox.uiConfig.MessageRelay.ReturnPath }}
-						</b>
-						<b v-else>{{ message.ReturnPath }}</b>.
-					</div> -->
 				</div>
 				<div class="modal-footer">
 					<button type="button" class="btn btn-outline-secondary" data-bs-dismiss="modal">Cancel</button>
@@ -13,7 +13,7 @@

 <body>
 	<rapi-doc id="thedoc" spec-url="swagger.json" theme="light" layout="column" render-style="read" load-fonts="false"
-		allow-authentication="false"
+		allow-authentication="false" sort-tags="true"
 		regular-font="system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'Noto Sans', 'Liberation Sans', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol', 'Noto Color Emoji'"
 		mono-font="Courier New, Courier, System, fixed-width" font-size="large" allow-spec-url-load="false"
 		allow-spec-file-load="false" allow-server-selection="false" allow-search="false" allow-advanced-search="false"
@@ -23,6 +23,66 @@
    "version": "v1"
  },
  "paths": {
+    "/api/v1/chaos": {
+      "get": {
+        "description": "Returns the current Chaos triggers configuration.\nThis API route will return an error if Chaos is not enabled at runtime.",
+        "produces": [
+          "application/json"
+        ],
+        "schemes": [
+          "http",
+          "https"
+        ],
+        "tags": [
+          "testing"
+        ],
+        "summary": "Get Chaos triggers",
+        "operationId": "getChaos",
+        "responses": {
+          "200": {
+            "$ref": "#/responses/ChaosResponse"
+          },
+          "400": {
+            "$ref": "#/responses/ErrorResponse"
+          }
+        }
+      },
+      "put": {
+        "description": "Set the Chaos triggers configuration and return the updated values.\nThis API route will return an error if Chaos is not enabled at runtime.\n\nIf any triggers are omitted from the request, then those are reset to their\ndefault values with a 0% probability (ie: disabled).\nSetting a blank `{}` will reset all triggers to their default values.",
+        "consumes": [
+          "application/json"
+        ],
+        "produces": [
+          "application/json"
+        ],
+        "schemes": [
+          "http",
+          "https"
+        ],
+        "tags": [
+          "testing"
+        ],
+        "summary": "Set Chaos triggers",
+        "operationId": "setChaosParams",
+        "parameters": [
+          {
+            "name": "Body",
+            "in": "body",
+            "schema": {
+              "$ref": "#/definitions/Triggers"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "$ref": "#/responses/ChaosResponse"
+          },
+          "400": {
+            "$ref": "#/responses/ErrorResponse"
+          }
+        }
+      }
+    },
    "/api/v1/info": {
      "get": {
        "description": "Returns basic runtime information, message totals and latest release version.",
@@ -139,7 +199,7 @@
          "https"
        ],
        "tags": [
-          "Other"
+          "other"
        ],
        "summary": "HTML check",
        "operationId": "HTMLCheckParams",
@@ -179,7 +239,7 @@
          "https"
        ],
        "tags": [
-          "Other"
+          "other"
        ],
        "summary": "Link check",
        "operationId": "LinkCheckParams",
@@ -414,7 +474,7 @@
          "https"
        ],
        "tags": [
-          "Other"
+          "other"
        ],
        "summary": "SpamAssassin check",
        "operationId": "SpamAssassinCheckParams",
@@ -1816,10 +1876,53 @@
      "x-go-name": "Result",
      "x-go-package": "github.com/axllent/mailpit/internal/spamassassin"
    },
+    "Trigger": {
+      "description": "Trigger for Chaos",
+      "type": "object",
+      "required": [
+        "ErrorCode",
+        "Probability"
+      ],
+      "properties": {
+        "ErrorCode": {
+          "description": "SMTP error code to return. The value must range from 400 to 599.",
+          "type": "integer",
+          "format": "int64",
+          "example": 451
+        },
+        "Probability": {
+          "description": "Probability (chance) of triggering the error. The value must range from 0 to 100.",
+          "type": "integer",
+          "format": "int64",
+          "example": 5
+        }
+      },
+      "x-go-package": "github.com/axllent/mailpit/internal/smtpd/chaos"
+    },
+    "Triggers": {
+      "description": "Triggers for the Chaos configuration",
+      "type": "object",
+      "properties": {
+        "Authentication": {
+          "$ref": "#/definitions/Trigger"
+        },
+        "Recipient": {
+          "$ref": "#/definitions/Trigger"
+        },
+        "Sender": {
+          "$ref": "#/definitions/Trigger"
+        }
+      },
+      "$ref": "#/definitions/Triggers"
+    },
    "WebUIConfiguration": {
      "description": "Response includes global web UI settings",
      "type": "object",
      "properties": {
+        "ChaosEnabled": {
+          "description": "Whether Chaos support is enabled at runtime",
+          "type": "boolean"
+        },
        "DuplicatesIgnored": {
          "description": "Whether messages with duplicate IDs are ignored",
          "type": "boolean"
@@ -1844,6 +1947,10 @@
              "description": "Whether message relaying (release) is enabled",
              "type": "boolean"
            },
+            "OverrideFrom": {
+              "description": "Overrides the \"From\" address for all relayed messages",
+              "type": "string"
+            },
            "ReturnPath": {
              "description": "Enforced Return-Path (if set) for relay bounces",
              "type": "string"
@@ -1885,6 +1992,12 @@
        "type": "string"
      }
    },
+    "ChaosResponse": {
+      "description": "Response for the Chaos triggers configuration",
+      "schema": {
+        "$ref": "#/definitions/Triggers"
+      }
+    },
    "ErrorResponse": {
      "description": "Server error will return with a 400 status code\nwith the error message in the body",
      "schema": {