blackhole.go

package main

import (
	"flag"
	"github.com/bradfitz/go-smtpd/smtpd"
	"log"
	"time"
)

var addr = flag.String("addr", ":25", "listen address")

// Just dump the mail
func onNewMail(c smtpd.Connection, from smtpd.MailAddress) (env smtpd.Envelope, err error) {
	log.Printf("%v %v", c.Addr(), from)
	env = new(smtpd.BasicEnvelope)
	env.AddRecipient(from)
	return
}

func main() {
	flag.Parse()
	server := smtpd.Server{
		Addr:         *addr,
		Hostname:     "", // use system hostname
		ReadTimeout:  60 * time.Second,
		WriteTimeout: 60 * time.Second,
		PlainAuth:    false,
		OnNewMail:    onNewMail,
	}

	log.Printf("Listening on %s", *addr)
	err := server.ListenAndServe()
	if err != nil {
		log.Printf("Failed to start server: %s", err)
	}
}