My home Internet connection is provided through a Netgear DG834 and, since I got the connection I have not been able to send mail (not a major problem since I generally work from an SSH account anyway). Over the weekend I finally managed to track down the problem. The DNS server on the router is providing timeouts when I make an MX request. Now I'm just waiting to see what technical support have to say for themselves. Worst comes to the worst I could hack the source or just tell my mail server to use my ISPs DNS servers directly (they work fine for MX requests). Hula doesn't look at /etc/resolv.conf anyway, so it would be little pain to start using it instead of Postfix and point it directly at Demon's DNS servers.