gosmtpd

Golang-based SMTP Listener

This is an unfinished SMTP listener. It receives connections, speaks SMTP, and discards any mail delivered to it. I might finish it some day, but I'm publishing it in the hope that someone will find bits of it interesting or useful.

This was my first non-trivial Go app, and is a port of a high-volume evented SMTP listener I'd written in C years ago. The equivalent C code is 5 times as much code, single-threaded, slightly slower, and took 10 times as long to get correct.

Building:

Install Go and git, then:

git clone https://github.com/die-net/gosmtpd.git
cd gosmtpd
go build

And you'll end up with an "gosmtpd" binary in the current directory.

Command-line flags:

-listen=":2525": The [IP]:port to listen for incoming connections on.
-rcpthosts="localhost": Comma-separated list of domains to accept mail for.
-servername="localhost": The hostname to show to clients

It defaults to dual-stack IPv4/IPv6. If you want IPv4-only, specify an IPv4 listen address, like -listen="0.0.0.0:2525".