Unable to connect to port 25 except from localhost
Posted on 2006-12-01
Hi any help on this would really be appreciated.
We recently took on IT support for a new customer who has a small busines server 2003 which the previous IT company had left partially installed. We continued the installation rather than reinstalling completly, which I now hope we can now avoid doing.
Almost everything is fine with the exception of port 25 connetivity. In a nut shell telnet to port 25 only works from the server itself on 127.0.0.1 or the local IP address of the server. Information on why or how this state of affairs has happened to get to this point is not availalbe. We look after a large number of these servers and have cross checked all optional settings within SMTP to no avail. If we add an additional port within the default SMTP default virtual server within exchange on port 26 we can connect via telnet and receive the banner from the SMTP service from inside the network and over the internet. We have tried to use port redirects on the firewall to get around this but port 26 only responds when connected to directly. If we redirect it to 25 on the public side of the firewall it does not respond.
This is a single network card installation with all the latest patches applied. I have read that the fault may relate to RAS so I have disabled and reenabled that to no avail. I have also read that implementing a second network card and activating the firewall on the server might resolve it but I would now want to understand why this is happening.
The server was running Sophos but we have removed that already to no avail. Policy manager appears to be the default configuration. much obliged for your help.