Simple Golang SMTP relay/proxy server

Topics
#golang #proxy-server #smtp-server #smtp-relay #ssl #load-balancer

Bernhard Fröhlich 32032c297c Merge pull request #38 from decke/dependabot/go_modules/github.com/google/uuid-1.3.0 4 ani în urmă
.github 6b21f52037 Bump wangyoucao577/go-release-action from 1.17 to 1.18 4 ani în urmă
cmd 009ae8f73a hasher: Check number of arguments 4 ani în urmă
LICENSE c707438ae8 Update MIT license template 6 ani în urmă
README.md 2afbe67407 Add Go Report Card badge 5 ani în urmă
auth.go 7f34fcbc99 gofmt: Fix formatting 4 ani în urmă
auth_test.go 7f34fcbc99 gofmt: Fix formatting 4 ani în urmă
config.go d8860fc917 Added external command support. 4 ani în urmă
config_test.go 441a53cfd9 Fix code formatting with gofmt -s 4 ani în urmă
go.mod 53e52de279 Bump github.com/google/uuid from 1.2.0 to 1.3.0 4 ani în urmă
go.sum 53e52de279 Bump github.com/google/uuid from 1.2.0 to 1.3.0 4 ani în urmă
logger.go 441a53cfd9 Fix code formatting with gofmt -s 4 ani în urmă
main.go 3f627d3281 Move AddReceivedLine before further processing. 4 ani în urmă
main_test.go 7f34fcbc99 gofmt: Fix formatting 4 ani în urmă
smtp.go b36ed8eddb net/smtp: adds support for the SMTPUTF8 extension 4 ani în urmă
smtprelay.ini d8860fc917 Added external command support. 4 ani în urmă

README.md

smtprelay

Go Report Card

Simple Golang based SMTP relay/proxy server that accepts mail via SMTP and forwards it directly to another SMTP server.

Why another SMTP server?

Outgoing mails are usually send via SMTP to an MTA (Mail Transfer Agent) which is one of Postfix, Exim, Sendmail or OpenSMTPD on UNIX/Linux in most cases. You really don't want to setup and maintain any of those full blown kitchensinks yourself because they are complex, fragile and hard to configure.

My use case is simple. I need to send automatically generated mails from cron via msmtp/sSMTP/dma, mails from various services and network printers to GMail without giving away my GMail credentials to each device which produces mail.

Main features

  • Supports SMTPS/TLS (465), STARTTLS (587) and unencrypted SMTP (25)
  • Checks for sender, receiver, client IP
  • Authentication support with file (LOGIN, PLAIN)
  • Enforce encryption for authentication
  • Forwards all mail to a smarthost (GMail, MailGun or any other SMTP server)
  • Small codebase
  • IPv6 support