Last week I ended up with a Actiontec Q1000 (replaced a PK5000 - long story). So I can set:
FWD from a server:22 to 192.168.0.10:22
FWD from anywhere:80 to 192.168.0.10:80
FWD from anywhere:25 to 192.168.0.10.25 wont' work.
From an external server I can telnet myserver 22 - works. I can telnet myserver 80 GET /index.html - works. But telnet myserver 25 just sits there - nothing... I can, from myinternalserver2 25 to myserver 25 and connect OK. I just can't get from external 25 to internal 25. I can't receive email from 'out there'. myserver iptables off - nope, Q1000 firewall off - nope.
Prob something stupid (not that I've everrrrrrr do that before).