msg2smtp.pl is designed to be a 'bridge' between Mutt and GNU Anubis:

 MUA (Mutt) --> msg2smtp.pl --> Anubis --> remote or local MTA

msg2smtp.pl can be used whenever you want to convert a mail message on STDIN
and talk to an SMTP server as output.

If you want to use this script with Mutt, add this to Mutt configuration file:
set sendmail="/PATHTO/msg2smtp.pl -h localhost"

If you run GNU Anubis on port 4000, you would put this line in your muttrc:
set sendmail="/PATHTO/msg2smtp.pl -h localhost -p 4000"

msg2smtp.pl takes a mail message on STDIN and relays it to an SMTP server.

msg2smtp.pl -h HOST [options]
  -h HOST        (hostname of SMTP server, often 'localhost')

  Options:

  -p PORT        (port of the SMTP server)
  -e HELO_DOMAIN (domain we use when to say helo to smtp server)
  -U USERNAME    (ESMTP auth username)
  -P PASSWORD    (ESMTP auth password)
  -m MECHANISM   (ESMTP auth mechanism - default is PLAIN)
  -d             (shows SMTP conversation and perl debugging)

EOF

