Yes, you can do it. But the only reason this would be worthwhile is if you plan to have your customers connect to this other port for their smtp. The other servers on the net would not know about qmail smtp running on this other port.
You basically need to copy your /var/qmail/supervise/qmail-smtpd directory and name it something else, like qmail-smtpd2 or something. Then you need to edit the qmail-smtpd2/run file and change the port. If you dont' know how, just post your run file and I'll show you where to change it. Then you link it into service with ln -s and it should fire up.
I do not have a directory called supervise in /var/qmail. I'v e looked for a directory called qmail-smtpd, but all I coud find was an executable. Do I need to copy the executable and then edit a config file?
tcpserver -H -R 0 nn /var/qmail/bin/qmail-smtpd /home/vpopmail/bin/vchkpw /bin/true &
Where "nn" is the additional port number you'd like to run on. Repeat as necessary, and note that this syntax is for vpopmail authentication; replace the vchkpw bit with whatever authentication method you're using.
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