The branch export use ADSL to dial-up. After pass NAT translation, access to private line server. After test and find that some service is normal, such as Ping, web, Telnet, but customer credit card service can't make normal communication.
1. By testing find NAT, routing are all no problem;
2. Modify MSS value, and the service become normal;
1. Link port limit;
2. NAT translation;
MSS is the biggest data segment that TCP packet can transfer every time, if the maximum MSS value plus header tailer is beyond the MTU value, will appear the the communication failure.