I have a Web Server, Exchange Server 2000 and my DNS server running on the same box and it is connected to my ISP . Right now I have a software firewall installed on this machine but I want to do away with it and put a Symantec Hardware Firewall instead, so now my config will look like:
ISP ---------> Firewall ---------> Web Server/Exchange Server/DNS Server
My question is what ports do I need to open on the firewall and also what changes do I need to make to the MX and A records in the DNS server. Since Exchange Server allocates dynamic ports for each client connection , how do I handle it.