msmtpd

Golang framework for building Simple Mail Transfer Protocol Daemons.

Фреймворк для создания почтовых серверов, написанный на Go.

Mirrors

• https://gitflic.ru/project/vodolaz095/msmtpd
• https://github.com/vodolaz095/msmtpd

Main features

1. Haraka hooks inspired CheckerFunc's being called on different actions of client (connection, HELO/EHLO command, StartTLS)
2. StartTLS, XClient, Proxy command support
3. Easy to implement logger interface
4. Build-in OpenTelemetry support - see dovecot_inbound and dovecot_outbound examples
5. Lot of plugins, including:
6. Dovecot plugin for authentication and LMTP mail delivery
7. Rspamd plugin for blocking spam
8. Plugins to deliver via 3rd party SMTP proxy, LMTP and SendMail.
9. Experimental Karma plugin to implement connection scoring (IP addresses making failed SMTP transactions will be blacklisted)
10. HELO/EHLO checkers, including complicated ones
11. Sender resolvable checker plugin to ensure sender's domain can accept our replies

Examples / Примеры

• custom_logger
• dovecot_inbound
• dovecot_outbound
• metrics
• minimal
• simple
• smtp_proxy

Inspiration / Источники вдохновения

• https://github.com/chrj/smtpd (часть кода)
• https://haraka.github.io/ (реализация функционала плагинов, общая идеология)
• https://github.com/albertito/chasquid/ (реализация проверки получателей и авторизации через сокеты Dovecot)

Minimal example / Минимальный пример

package main

import (
	"log"

	"github.com/vodolaz095/msmtpd"
)

func main() {
	server := msmtpd.Server{
		Hostname:       "localhost",
		WelcomeMessage: "Do you believe in our God?",
	}

	err := server.ListenAndServe(":1025")
	if err != nil {
		log.Fatalf("%s : while starting server on 0.0.0.0:1025", err)
	}
}

Server log / Протокол работы сервера

2023/08/02 16:30:11 INFO [1cca484c18ebe494240b196bc60ee39c]: Accepting connection from [::1]:34142...
2023/08/02 16:30:11 INFO [1cca484c18ebe494240b196bc60ee39c]: EHLO <localhost> is accepted!
2023/08/02 16:30:11 INFO [1cca484c18ebe494240b196bc60ee39c]: MAIL FROM <sender@example.org> is checked by 0
SenderCheckers and accepted!
2023/08/02 16:30:11 INFO [1cca484c18ebe494240b196bc60ee39c]: Recipient <recipient@example.org> will be 1st one in
transaction!
2023/08/02 16:30:11 INFO [1cca484c18ebe494240b196bc60ee39c]: Subject: test Wed, 02 Aug 2023 16:30:11 +0300
2023/08/02 16:30:11 INFO [1cca484c18ebe494240b196bc60ee39c]: Body (264 bytes) checked by 0 DataCheckers successfully!
2023/08/02 16:30:11 WARN [1cca484c18ebe494240b196bc60ee39c]: Message silently discarded - no DataHandlers set...
2023/08/02 16:30:12 INFO [1cca484c18ebe494240b196bc60ee39c]: Closing transaction.
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Accepting connection from [::1]:50596...
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: EHLO <localhost> is accepted!
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: MAIL FROM <sender@example.org> is checked by 0
SenderCheckers and accepted!
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Recipient <recipient1@example.org> will be 1st one in
transaction!
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Recipient <recipient2@example.org> will be 2nd one in
transaction!
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Recipient <recipient3@example.org> will be 2nd one in
transaction!
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Recipient <recipient4@example.org> will be 4th one in
transaction!
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Subject: test Wed, 02 Aug 2023 16:30:31 +0300
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Body (334 bytes) checked by 0 DataCheckers successfully!
2023/08/02 16:30:31 WARN [4dfe768e04186309306b1af3194b05c4]: Message silently discarded - no DataHandlers set...
2023/08/02 16:30:31 INFO [4dfe768e04186309306b1af3194b05c4]: Closing transaction.

Client log while testing smtp server / Вывод клиента при тестировании почтового сервера

$ swaks --to recipient1@example.org,recipient2@example.org,recipient3@example.org,recipient4@example.org \
    --from sender@example.org \
    --server localhost --port 1025 \
    --timeout 600

=== Trying localhost:1025...
=== Connected to localhost.
<- 220 Do you believe in our God?
-> EHLO localhost
<- 250-localhost
<- 250-SIZE 10240000
<- 250-8BITMIME
<- 250 PIPELINING
-> MAIL FROM:<sender@example.org>
<- 250 Ok, it makes sense, go ahead please!
-> RCPT TO:<recipient1@example.org>
<- 250 It seems i can handle delivery for this recipient, i'll do my best!
-> RCPT TO:<recipient2@example.org>
<- 250 It seems i can handle delivery for this recipient, i'll do my best!
-> RCPT TO:<recipient3@example.org>
<- 250 It seems i can handle delivery for this recipient, i'll do my best!
-> RCPT TO:<recipient4@example.org>
<- 250 It seems i can handle delivery for this recipient, i'll do my best!
-> DATA
<- 354 Ok, you managed to talk me into accepting your message. Go on, end your data with <CR><LF>.<CR><LF>
-> Date: Wed, 02 Aug 2023 16:30:31 +0300
-> To: recipient1@example.org,recipient2@example.org,recipient3@example.org,recipient4@example.org
-> From: sender@example.org
-> Subject: test Wed, 02 Aug 2023 16:30:31 +0300
-> Message-Id: <20230802163031.059039@localhost>
-> X-Mailer: swaks v20190914.0 jetmore.org/john/code/swaks/
->
-> This is a test mailing
->
->
-> .
<- 250 Thank you.
-> QUIT
<- 221 Farewell, my friend! Transaction 4dfe768e04186309306b1af3194b05c4 is finished

Support development / Поддержать разработку

https://www.tinkoff.ru/rm/ostroumov.anatoliy2/4HFzm76801/