multiple VPN Clients (L2TP) behind a NAT device connects to ISA server 2004

From: "Andreas Bladh" <ab@xxxxxxxxxx>
Date: Thu, 18 May 2006 16:24:19 +0200

Dear all,

We have an ISA server 2004 and we use it to terminate our VPN (l2tp)
clients. It works really well, even when clients are behind NAT devices.

The problem we have discovered is when more then one client is behind the
same Nat device or firewall, only the first one that connects can establish
an ipsec tunnel?

Is this a limitation on the ISA 2004 EE server, limitation on the L2TP ipsec
NAT-T protocol, or is it a limitation on the NAT device/firewall the client
is behind.

Please advise me in this issue. If the problem is the NAT device/firewall
the clients are behind; does it exist any firewalls that can handle this?
What specification must the Nat device then have?

Thanks in advance,

Andrea Bladh

.

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