IPSec Passthrough limitations on a LINKSYS Wireless Router.  Model Number WRT54GS

Posted on 2004-09-02
Last Modified: 2013-11-29
How Many IPSEC passthough tunnels can you have active at the same time through this Linksys Wireless Router?    
Question by:brianmeyers
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Expert Comment

ID: 11968705

You would need the VPN model to get more, like the WRV54G


Author Comment

ID: 11968987
is this a firmware limitation within the Linksys or a IPsec issue?

Author Comment

ID: 11969024
oh and one other comment.  lrmoore suggested a WRV54G model but i didn't read anything about "maximum passthrough tunnels" just that you can configure multiple vpn tunnels to this HW device.  Is this you you perceive it?
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Accepted Solution

jasperomalley earned 50 total points
ID: 11984865
It's both a firmware limitation and an IPsec issue, depending on how you look at it. It's fairly easy for the router to track IPsec connections from one internal hosts to one external host, or even any number of internal hosts to different external hosts, but it becomes more complicated when you have multiple internal hosts creating VPN tunnels to the same external host. So, most broadband router and SOHO firewall manufacturers just give you the ability to do one VPN passthrough tunnel and say they're done with it, in order to avoid having to program for the more complex cases.

A better solution all around is to use NAT Traversal (NAT-T), in which the VPN client and server encapsulate IPsec connections in UDP packets sent to/from UDP port 4500 on the server, since most router/firewall devices doing NAT can handle UDP translation easily. Most VPN server devices (and their clients) can do NAT-T nowadays, although some devices might require a firmware upgrade in order to do so.

Author Comment

ID: 12104224
so would it be safe to say that you could have multiple remote user VPN's passing through the Linksys device back to a concentrator that supports NAT-T?  Most of my remote user VPN's have been setup using IPsec of TCP to alleviate PAT issues through the remote user FW's.  Will i have the same issues if i use NAT-T?

Expert Comment

ID: 12104631
Yes, it would be safe to say that you could do that. NAT-T was designed specifically to address the problems with sending IPSec traffic through NAT/PAT devices.

Author Comment

ID: 12104767
thanks for your assistance!

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