Port Forwarding on RV042G

[sp1152211811]

Ok I'm Stuck!  I need to route mail to a different port.  I found that UPnP is the only place to enter a different end port.  However, I can't figure out how to enter the access rule for that service.  I have researched the forums and found the UPnP info but no further instructions to create a rule.  When I create the service in UPnP, add to list, then go to access rules to allow through the firewall, the service I created is not in the list.  Please assist!

[sp1152211811]

Thanks Donders for your reply.  I have settled the issue and have configured the RV042G to my satisfaction.  I did go with the 1:1 NAT - using Access Rules - and everything works fine.  I run a mail server but I have set my mx records to filter all mail through a spam scrubber and then deliver to my mail server.  I don't want any other MTA to connect to my server and was receiving mail from the spam service at 2525 then redirecting to 25.  However, using the Access Rules and restricting the source addresses, I can deliver directly to 25. 

The spam service has 7 non-contiguous addresses that i have to enter into access rules.  Since there is a limit of 30 access rules, I thought port translation would be a better solution.  AND - I can still do it if I set a UPnP rule - 2525->25 on the WAN address to be delivered to the mail server.  It does work but leaves a security vunerability.  Well at least I have some options in that regard.