Couple of PIX 506e issues with concerns to remote client

Unanswered Question
Jan 28th, 2008

I have 3 sites running 506e Pix's, with a private VPN tunnel setup between each. This is all fine, we can hit all of terminal servers from any inside location.

I have remote access set to just my main location, so anyone needing to connect in from the out side will come in just to that Pix.

Issue 1.

When I connect as a remote cisco client, I can not ping my other two locations.

Issue 2.

Occasionally, when my remote clients establish a connection, they will not be able to authenticate to any of my terminal servers. This seems to happen when they are creating a tunnel from behind a wireless router, which is also set up for NAT'ing, and it's private network address, is using the same network address range that I'm using my private network (192.168.1.0)

Thanks for any help

Ron

I have this problem too.
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husycisco Mon, 01/28/2008 - 11:48

Hi Ron

Issue 1.

You terminate your L2L and RA VPN connection at outside interface. For having traffic possible between them, you have to let IPSEC traffic enter and exit the same interface. Following is the command that you have to issue

same-security-traffic permit intra-interface

Keep in mind that you have to specify the RA VPN pool in NAT statements of remote sites. Assuming that you have exempt NAT configuration (nat 0), you need an ACL like following

access-list inside_nat0_outbound permit ip vpnpool vpnpoolnetmask remotesite remotesitenetmask

Issue 2

Adding the following line will resolve the unability of connection from NATing devices

crypto isakmp nat-traversal 20

One of the most important thing in architecture is choosing IP octets that are not commonly used. Same subnet in each sites issue is one of the head aches in architecture. And there is no way of solving this except using not common address scheme.

Regards

acomiskey Mon, 01/28/2008 - 11:55

husycisco,

Are you sure you have to define that traffic in the nat exemption acl? After all, the traffic isn't hitting the inside interface, therefore the nat (inside) 0 command would have no effect right?

husycisco Mon, 01/28/2008 - 13:16

Adam

You are correct, dont know what I was thinking during suggesting that nat 0 rule.

Ron

This nat exempt rule must be assigned to outside interface like

nat (outside) 1 access-list outside_nat0_outbound outside

access-list outside_nat0_outbound permit ip vpnpool vpnpoolnetmask remotesite remotesitenetmask

or if you want to NAT or PAT, the config is

nat (outside) 2 vpnpool vpnpoolmask outside

global (outside) 2 x.x.x.x y.y.y.y

(x.x.x.x can be a single IP or a x class subnet like 172.20.5.0/24)

Keep in mind that this VPN POOLs value must be entered in split tunnel acl, crypto acl (the NATed IP range if exempt nat is not used), and in the remote end device of L2L VPNs.

Dont know if the old code supports above, I assume 6.3(5) will support.

Regards

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