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Vpn isa 2004 back to back Scenario

Posted on 2006-07-05
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Last Modified: 2013-11-16
Once again guys. Should have stuck to cisco.

Well isa backend server is set up as a vpn server. Vpn client access enabled and the vpn client access is configured to use pptp.

I then publish this server on the FE box, telling isa to listen on a particular address on the external interface.

I get error 800 enable to estabish vpn connection. when monitoring the FE server is find that a connection has being routed to the BE server which is denying it.

I checked all the rules and they looked ok. any suggestions?
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Question by:kiddkapurcjw
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xmaveric earned 500 total points
ID: 17045530
This error can be the result of having outdated firmware on a router.

To see if this is the problem, perform a network trace. If the router advertises a 0 window size in the TCP handshake on port 1723, update the firmware.

Some other reasons this error occurs include:

The PPTP or L2TP server is not reachable. A firewall could be blocking traffic; the server name specified in your connection could be incorrect.
 
There are no free VPN ports on the server (over-subscribed - maximum number of users already connected).

1) if you have firewall, open TCP Port 1723, IP Protocol 47 (GRE).
2) make sure you can reach the VPN server by using ping.  Sometimes, poor connection can cause this issue too.
3) You may need to updated firmware on a router or firewall if other OS (win9x/nt/me/w2k) works except XP.
4) The VPN server may not be able to get IP from DHCP for the VPN client. So, you may want to re-configure VPN host networking settings. For XP pro VPN host, go to the Properties of the VPN>Network, check Specify TCP/IP address and Allow calling computer to specify its own IP address, and uncheck Assign TCP/IP addresses automatically using DHCP.
5) Make sure other secure software blocks your access, for example, if you use Norton secure software, you may need to add the remote client's IP so that the client can access.
6) If your VPN running on a Windows RRAS with NAT enabled, you may want to check the NAT settings.

Error 800 could indicate a problem with authentication. Likely causes include a firewall blocking PPTP traffic (either by your ISP or a local personal firewall such as ZoneAlarm or Tiny.)
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