IPv6 Network Administration

POP/IMAP

We've seen that there are many options for IPv6 mail transport agents on Unix-like systems, both in terms of out-of-the-box support and patches for the remaining well-known systems. In terms of POP and IMAP we are similarly well-provided for.

WU-IMAP

The University of Washington's IMAP server (available from http://www.washington.edu/imap/) doesn't much care if it is run over IPv6, IPv4 or something completely different.^[9] So, if your inetd supports IPv6, and you're already using this IMAP daemon, then running IMAP over IPv6 is as easy as editing your /etc/inetd.conf and adding a line like:

imap    stream  tcp6     nowait  root    /usr/sbin/tcpd imapd

If you need logs of where your IPv6 IMAP connections are coming from, then unfortunately WU-IMAP can't do this for you. However, you can use TCP wrappers to do it instead. For example, consider the following line in /etc/hosts.allow:

imapd: ALL : severity mail.info : allow

This will allow all connections to the program imapd, syslogging them to the mail facility at level info. Naturally, your vendor's inetd (or xinetd) may provide additional logging options.

Courier-IMAP

Courier-IMAP is a POP 3 and IMAP server available from http://www.courier-mta.org/imap/. It works with Qmail style Maildir mailboxes and has lots of nice features, like supporting POP and IMAP with TLS.

When you compile Courier-IMAP, it automatically enables IPv6 if it detects support for IPv6 in the operating system. In our experience this is a no-brainer once installed, ...