mconnect − connect to the SMTP server on a host
mconnect [ host [ port ] ]
mconnect connects via IP[v4|v6] to port on host. It sends its input to host, adding a CR to each line. Meanwhile it prints anything it receives from host.
If port is not supplied, mconnect uses port 25 (SMTP).
If host is not supplied, mconnect connects to localhost.
tcpclient(1)