I have a web server serving public pages under a continuous barrage of requests attempting to login with various combinations of credentials. I would like to thwart these by blocking IP addresses and ports. From the Security log I can see the IP address and port where these requests eminate, and I have selectively blocked various IP addresses. However, if I can block a range of ports that would be much more efficient.
So here are my questions...
1) Is blocking IP addresses and ports the best strategy? Or is there a better strategy?
2) Can someone provide a standard list of ports that must remain open for the web server to function properly? ie, port 80 obviously must remain open. I am looking for a consolidated list of standard ports for web, ftp, mail, and other services.