02-06-2012 05:18 AM - edited 02-21-2020 05:51 PM
I have remote access vpn configured on cisco 2901 router. Everything works good exept ipad 2 3g. When i am connecting with ipad from 3g network it connects but it is unable to access corporate resources. I talked to my telephone provaider and they told me that they have some nat problems with ESP. and adviced me to force vpn clients to use udp ports 500 and 4500. How i have to configure my router to accomplish this ?
Thanks in advance
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02-06-2012 11:01 AM
Hello,
Isakmp uses port UDP 500 for the managment connection establishment ( Phase 1).
NAT-T ( used when they are nat devices in between two VPN endpoints) uses port UDP 4500.
So on your Router NAT-T is configured by default, all you got to do is if you have an ACL on the outside interface allow this traffic (Isakamp and NAT T) On some of the newer IOS versions you do not have to apply the ACL as by default the VPN traffic (encrypted traffic bypasses the ACL).
So your requirement is done by default, great thing right!! You can let your Telephone provider you are ready for the test.
Julio
Do rate all helpful posts!!
02-06-2012 11:01 AM
Hello,
Isakmp uses port UDP 500 for the managment connection establishment ( Phase 1).
NAT-T ( used when they are nat devices in between two VPN endpoints) uses port UDP 4500.
So on your Router NAT-T is configured by default, all you got to do is if you have an ACL on the outside interface allow this traffic (Isakamp and NAT T) On some of the newer IOS versions you do not have to apply the ACL as by default the VPN traffic (encrypted traffic bypasses the ACL).
So your requirement is done by default, great thing right!! You can let your Telephone provider you are ready for the test.
Julio
Do rate all helpful posts!!
02-09-2012 10:20 PM
i added this command and everthing works perfect
crypto isakmp nat keepalive 20
thanks for your reply
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