I am using Avaya VPN client & when I am getting connected succesfully to IPSec VPN Server, it is showing in status that IP NAT-Transversal is active on port 10001. In this case my IP is behind the NAPT router. When I am checking the logs, it shows that the request from my IP has gone through port 10001 (UDP) & hist server IP on port 10001 (UDP).
But in some cases when the request from my IP is going through any other port than 10001 & hit server on port 500, I am not getthing authenticated for VPN. So, I am understanding that for my VPN connection, the requested has to be go on port 10001 of VPN Server and port 10001 of client.
Please suggest how I can force every IPSec request to my VPN server to hit on port 10001 (UDP) so that i will not face any issue.