Fwd: specify SMTP relay server in mutt

[Sunhux G]

What Harris gave with mailx is probably what I'm looking for,
just that I can't get the syntax right with -a (or even if I leave
out the -a option) :

# mailx -s "test" -a /tmp/tst.tar.gz -S "smtp=172.20.1.92" recipient at xxx.com
< /tmp/cis/group.tmp
    Or (without the -u )
# mailx -s "test" -a /tmp/tst.tar.gz -u whitelistid at xxx.com -S
"smtp=172.20.1.92" recipient at xxx.com < /tmp/cis/group.tmp
mailx: invalid option -- a
Usage: mail [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...
            [-- sendmail-options ...]
       mail [-iInNv] -f [name]
       mail [-iInNv] [-u user]
What did I miss?  I've tried with uuencode (referring to some
examples on the Net) too but no joy


SH