How to find if Microsoft ISA server (Proxy Server) is using X Forwarded or if they are configured to mask all the internal IPs.

Hi

We use Microsoft ISA server as Proxy servers for two group of users within our network and my predecessors had set up these servers in the past. Our networking team are asking me, if these proxies are using X Forwarded or if they are configured to mask all the internal IPs.

I am not familiar with Microsoft ISA, please can you provide some tutorials as how to find whether these proxies are using X Forwarded or if they are configured to mask all the internal IPs.

Thanks in advance.