VPN access through NAT

[mufka]

I have a Cisco 1601R that is connected through S1 to a T1. I have NAT setup on the router. Everything works ok except access from the internat network to VPNs on the outside. Is there some protocol I have to allow specifically. My access-list permits all.

 

[mufka]

It looks like the VPN I'm accessing (Raptor) uses IP 50 and IP 51 and UDP 500. Can I allow these through the NAT?

Thanks for any help.

 

[andrewalx]

Hi.
VPN doesn't interfare with NAT if your tunnel har S1 address as source address. You can apply inbound access-list like this
permit gre host <T1 addr> host <S1 addr>
permit udp host <T1 addr> eq 500 host <S1 addr> eq 500
adn outbound access-list like this
permit gre host <S1 addr> host <T1 addr>
permit udp host <S1 addr> eq 500 host <T1 addr> eq 500