ways/tools to check for ports required by applications to facilitate firewall rules creation

[Yong Huang]

> Any script (that's rapidly/continously running) or free tools 
> that I can run on the source & destination servers that could 
> help me determine which ports are the servers attempting to 
> connect to ?

-p option of netstat can associate ports with processes. lsof (the tool by Vic
Abel) can show you more. If that doesn't work for you, try:

strace -e trace=network your_application

Yong Huang