The mail server resides at a 172.16.0 net and the client machines
at a 192.168.2.0 net. If I have understood the documentation
correctly, vpopmail must be configured with "--enable-roaming-
users" if the client machines are on a different net. Correct?
The entry in /home/vpopmail/etc/tcp.smtp is
172.16.0.:allow,RELAYCLIENT="" and I have done
Maybe I'm missing something too but shouldn't the contents of the
tcp.smtp file say:
since the connections are coming FROM the 192 network?
However, since this is a qmail-smtpd generated error you may want to
address questions to the qmail.org mailing list (not that any of
these fine people could answer your question mind you).