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cannot use Nortel vpn with ADSL router ?

Hi,

I have a static IP/ADSL line and use a Zyxel Prestige 643 router as the modem/router+firewall. The router has NAT enabled and serves as the DHCP server for my local LAN. I am able to do almost everything except VPN out to my work place (we use Nortel's Contivity VPN client). I opened up port 500 (UDP) to allow ISAKMP traffic - this got me past the first stage. A network trace revealed 3 packets being exchanged for ISAKMP aggressive on srcport==dstport==500. The subsequent packet from my machine seems to choose a random UDP port. I have seen port# between

1450-1700 being used. I think this is an IP packet encapsulated in UDP. However, I never get a response back since that port is typically blocked on my firewall. I continue to see ISAKMP informational packets on port 500 but at about this point the VPN software gives up.

Has anyone encountered a similar problem ? Any suggestions on what I can do to get the traffic to pass through with out opening up my firewall.

Thanks, ~sri

srikantkt (at) REMOVE_SPAM gmail (dot) com

Reply to
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I'm using the Nortel Extranet client with a Linux-based router/firewall. I created a rule to accept all traffic to/from our two VPN servers, regardless of protocol or port. And since I was getting timeouts if there wasn't activity, I created a rule to force all incoming traffic from the VPN servers to the specific IP address that is the only one that runs the VPN client.

Reply to
Ken

Can't use nortel VPN thru NAT. Period. End of story.

Reply to
T. Sean Weintz

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