IPSec Connection Ports

Question

i configured a VPN server with IPSec to surfe secure at public networks. At generally it works. Now i would like to access my vpn server from my campus. Here i can't get any connection.

I know, that the campus administrator block all ports under 1024 except http and https. I also know, that IPSec use UDP 500 and 4500.

1. Do you think it is enough to change the port UDP 500 to a higher port? Are there other ports important for IPSec under 1024?
2. Does IPSec work with TCP instead UDP?

Answer 1

1. IPsec has 2 phases, the first phase involves IKE(aka ISAKMP) protocol which uses udp port 500.Port 4500 is only used when dealing with nat traversal.

2. The standard defines the phase 1 using udp protocol, and the software is implemented in the same manner.