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Rubes_sw · Posted: Mon Mar 01, 2004 2:09 pm Post subject: Blocking Ports

Can or is there a dll or method to monitor all ports coming into a machine and block all the ports except for eg.

80, 21, 25, 110 (Http, Ftp, Smtp, Pop3) etc.

A simple firewall !

I want to build a firewall, so that connections coming in from another ip on our lan go through this firewall and then on to a proxy (which is the connection to the Internet).

Any ideas? Any Dll's ?

Nathan

Skit3000 · Posted: Mon Mar 01, 2004 3:24 pm Post subject:

The monitoring part can be done by calling "netstat" every x-seconds. I also believe that the internet DLL Commercial Research made can do the same, but I'm not sure about that. For your other question, I found some code which could be useful (Visual Basic):

http://www.codeproject.com/internet/drvfltip.asp
http://www.codeproject.com/internet/smfirewall.asp

jules · Posted: Mon Mar 01, 2004 6:15 pm Post subject:

Yes, the portmon example in the VDS Internet Suite does exactly that. It logs the IP of anyone trying to connect to a particular port.