VPN issues when client AND server are behind NAT/Firewall

From: Swaroop Kumar (swaroop1967_at_yahoo.com)
Date: 05/20/04 

Date: 20 May 2004 13:19:29 -0700

Hello:

    I work for a consulting company and we are currently executing a
project for a customer who is located across the country. In order to
avoid frequent travel for integration, testing & deployment of the
various software modules we are developing, we decided to request the
client for VPN access to their network. All our desktops are behind a
firewall/NAT router and we are assigned DHCP addresses. In addition,
the VPN server in the client's site is behind a similar firewall/NAT
setup. Because of all the IP masquerading taking place, we are unable
to establish a successful VPN connection unless one of the two
machines is in a DMZ (outside the firewall, openly accessible on the
internet). The VPN setup at the client is by NetScreen and the
operating environment on both sides is primarily Microsoft-based.

    Can somebody please advise us of solutions from their past
experiences or at least suggest possible workarounds/debugging methods
to resolve this issue?

Thanks a lot in advance,
Swaroop

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