System: FC5 (followed the Perfect Setup howto) I am trying to relay mail for 1 domain through the FC5 box on my DMZ to my SBS2003 exchange server on my LAN. I have tried to set the mailserver option to external and added an MX record with weight of 10 pointing to the lan IP address. I have changed the standard ISPConfig generated Record to weight 20. In the hope that if my sbs2k3 server is not online (after all its microsoft) that the FC5 server will be a back up. Is this possible? im a bit of newbie to this and i cant find a simple "this is what you do........" document on this.