I'm having some problems with courier-imap and STARTTLS not being enabled. The problem is that the env-vars in '/etc/courier-imap/imapd' aren't being expanded and result in: IMAP_CAPABILITY_TLS='$IMAP_CAPABILITY AUTH=PLAIN' IMAP_CAPABILITY_TLS_ORIG='$IMAP_CAPABILITY_ORIG AUTH=PLAIN' being passed to /usr/sbin/imaplogin. After a lot of debugging I've discovered part of the reason is a non-standard version of tcp-env (/usr/bin/tcp-env) that takes an undocumented argument "-f file", where 'file' contains environmental variables. The service definition in /etc/xinetd.d/courier-imap has this: server = /usr/bin/tcp-env server_args = -R -f /etc/courier-imap/imapd /usr/sbin/imaplogin /usr/lib/courier-imap/authlib/authpsa /usr/bin/imapd Maildir By peeking at the the binary using $ hexdump -C /usr/bin/tcp-env I can see the additional argument: "rRt:f:.PROTO." I've checked the qmail source, and the Plesk patches including patch-z04-tcp-env. Where can I find the source-code for the modified tcp-env ?