Both computers run Linux. A port scan of the machine with the open port 25 from inside the same lan. PORT STATE SERVICE 25/tcp open smtp port scan from the web port 25 is open port 25 can receive mail. A port scan of the machine with the open port 25 from my lan. PORT STATE SERVICE 25/tcp filtered smtp I can't telnet to port 25 of the computer on the other lan so it is hard to debug it. I tried making this computer a DMZ.