What is port 25 filtering?
In order to improve network security, reduce the spread of email-borne viruses, and reduce the overall volume of spam on the Internet, Qwest encourages customers who are not running their own email servers to turn on port 25 filtering. Port 25 is primarily used for communication between email servers, so filtering out traffic on port 25 helps to protect your computer(s) from being used by a virus (or other malware) to send or relay spam. It has become a recognized industry best practice on the Internet for service providers like Qwest to filter traffic on port 25. Qwest recommends that you enable port 25 filtering unless you are running your own email server.
