Multiple instances

Hello there. This is probably a stupid question, but how do I run multiple instances of radiusd on the same machine, listening on different ports? I have two configuration directories: /usr/local/etc/raddb /usr/local/etc/raddb2 which specify ports 1812 and 1813 respectively, so I thought I'd be able to issue the following commands: radiusd -d /usr/local/etc/raddb radiusd -d /usr/local/etc/raddb2 This doesn't seem to work however, as the second command seems to have no effect, ie. I see the first radiusd process running but never the second. Can anyone help please? Thanks, Mike