feat(dns): add update functionality for DNS records (MX, SRV, TXT)

- Implemented UpdateMXRecord, UpdateSRVRecord, and UpdateTXTRecord functions in their respective repositories.
- Added UpdateRecord method in dns service to handle updates for various DNS record types.
- Updated router to include a new route for updating DNS records.
- Enhanced error messages for record updates in messages.go.
- Modified the frontend forms to support editing DNS records with improved UI components.
- Refactored existing domain management code to remove unused update functionality.
- Improved email handling by adding MX record validation during email delivery.

3 files changed, 27 insertions, 1 deletions

diff --git a/utils/email/defaults.go b/utils/email/defaults.go
index 56bee21..5aa11de 100644
--- a/utils/email/defaults.go
+++ b/utils/email/defaults.go
@@ -4,4 +4,4 @@ const (
 	AddressJoiner = ", "
 	LogPrefix     = "Email"
 	SnippetLength = 200
-)
\ No newline at end of file
+)
diff --git a/utils/smtp/messages.go b/utils/smtp/messages.go
index 1c82ab6..0fd280b 100644
--- a/utils/smtp/messages.go
+++ b/utils/smtp/messages.go
@@ -7,6 +7,7 @@ const (
 	InvalidCredentials     = "Invalid credentials."
 	ListenFailed           = "Failed to start %s listener: %v"
 	MailFrom               = "Mail from: %s"
+	MXLookupFailed         = "MX lookup failed for %s: %v"
 	MessageParseFailed     = "Failed to parse incoming message: %v"
 	MessageReceived        = "Message received (%d bytes) from %s to %v."
 	MessageStoreFailed     = "Failed to store message: %v"
diff --git a/utils/smtp/session.go b/utils/smtp/session.go
index ef5ddc7..e9efbd9 100644
--- a/utils/smtp/session.go
+++ b/utils/smtp/session.go
@@ -10,6 +10,7 @@ import (
 	"dove/utils/storage"
 	"fmt"
 	"io"
+	"net"
 	"strings"
 	"time"
 
@@ -63,6 +64,12 @@ func (self *Session) Data(messageReader io.Reader) error {
 	deliveredToLocal := false
 
 	for _, recipientAddress := range self.toAddresses {
+		recipientDomain := extractDomain(recipientAddress)
+		if recipientDomain == "" || !domainHasMXRecords(recipientDomain) {
+			logger.Warnf(LogPrefix, UnknownRecipientDomain, recipientDomain)
+			continue
+		}
+
 		recipientMailbox := mailRepo.FindMailboxByAddress(recipientAddress)
 		if recipientMailbox == nil {
 			aliasMailbox := mailRepo.FindMailboxByAlias(recipientAddress)
@@ -164,3 +171,21 @@ func deliverToLocalMailbox(mailbox *mailModel.Mailbox, parsedEmail *email.Parsed
 
 	return nil
 }
+
+func extractDomain(emailAddress string) string {
+	atIndex := strings.LastIndex(emailAddress, "@")
+	if atIndex < 0 || atIndex >= len(emailAddress)-1 {
+		return ""
+	}
+	return emailAddress[atIndex+1:]
+}
+
+func domainHasMXRecords(domainName string) bool {
+	mxRecords, lookupError := net.LookupMX(domainName)
+	if lookupError != nil {
+		logger.Debugf(LogPrefix, MXLookupFailed, domainName, lookupError)
+		return false
+	}
+
+	return len(mxRecords) > 0
+}