I'm having an issue with out external IP being blacklisted, I have been researching this all day and have followed these instructions in order to only allow stmp traffic to flow from my mail server.
I would like to narrow down the issue so i can find the client thats causing the issue. Some of the posts i have read and the info i received from the CBL say to monitor traffic on port 16464 but i'm not sure how to setup that rule on the Cisco firewall.
Message from CBL is below -
"If this IP address is a NAT gateway, it should be possible to find which computer on your internal network is infected by implementing a filter on your firewall to detect and log attempts to send UDP packets to the Internet with a destination port number of 16464."
Can someone give me some step by step instructions on how to set this up? and what and where to look for when it is?