Topic: protocol ESP and AH

[sage major]

I am trying to set up a vpn to my office.  This is what I was told
make sure you allow VPN traffic (protocol 17 [UDP] at source port 5000 and destination port 501. Protocols 50 [ESP] and 51 [AH] must be opened inbound and outbound.

I did the port 501 and 5000 using the port forwarding rpm but what are ESP and AH and how do I forward them?