qacafe - ip test solutions
Knowledge Base > General > Is there any value is running the tests using different IP addresses for the WAN and LAN configuration?

Is there any value is running the tests using different IP addresses for the WAN and LAN configuration?

Yes. Some of the functionality tested is dependent of the actual IP addresses used. For example, when a NAT router translates the FTP PORT command, it has to adjust the size of the TCP segment depending on the size difference between the router's WAN side address and the client's LAN side address. The FTP PORT command sends the IP address as text, so the size can change dynamically. Other ALGs such as H.323 and MSN Messenger also look at the IP address information in each packet.