In our networking environment, we need to allow a few tailor make applications as well as several others Applications Utilities such as backup, database, security/anti-virus software etc. All those applications located in different Zones in our networking environment separated by Firewalls.
We need to do a Security Auditing exercise very soon and can only open the necessary ports that those application required. As some application requires many ports to be opened in order to be operational and some don't even have full documentation what TCP/UDP ports required.
My questions is what is the most efficient way to find out what is the required/necessary ports required to be opened on the firewall that separate each zones. I know I could use NETSTAT for each applications but is that a more efficient or systematic way to achieve this task.
Thank you so much for your kind advice in advance.