Configuring Cisco VPN Client / Windows XP

I'm trying to get one XP system to access web pages using a Cisco VPN client. The system had been working fine. Details are below.

One question I have is: Given that we see the Ethernet NIC interface and given that we see the VPN client as a network interface: How does the sytem decide which of these "interfaces" to use in supporting things like Internet Explorer? It *appears* that all the interfaces are working but those pages that require the VPN aren't coming up. Thus my (probably dumb) question.

Presently we can see normal web pages both http and https. But we cannot access an https page that probably requires connection via the VPN.

So, my other question is: How might this be fixed? I'm tempted to reinstall the VPN client, repair the TCP/IP stack, ....

Any suggestions regarding both questions would be greatly appreciated.



*****Background: We're working on a customer's system with *no* technical reference information or support. It's rather strange indeed but I'm sure we'll figure it out. I could use some advice / help:

The system has the following:

A Westell DSL Modem - working fine. (Initially, the modem was set up to be dialed by PPPOE software in the PC. I changed this so that the modem will dial and stay connected by itself. Maybe this was a mistake but I don't see how.)

Ethernet NIC: as normal, an ethernet NIC shows up as a network interface.

PPPOE interface: IF the PPPOE software is started, then it shows up as an interface. But now that the modem is automatic, this software doesn't do anything. So, I just don't start it up at all. I've seen lots of systems transitioned from using "dialing" software to simply letting the modem do the connection work - so I'm very used to this part.

There is a Cisco VPN client installed on the computer. I'm not so used to this..... When the VPN client is started, it connects. So far this seems good.

So, the current network interfaces showing are: Ethernet NIC - connected with IP address DHCP from the modem. VPN "interface" - connected with IP address that must be coming from the other end of the VPN... PPPOE interface - not connected / used. Dialup connection - not connected / used.

For the critical purpose of the sytem, Internet Explorer 6 is being used for all interfacing - to interactive web pages. The customer reports that the distant servers recently switched from http to https pages. After this was done, they report that one of the client computers stopped connnecting to the pages. So, our task is to get it working again. (Because all other clients in this system are working, we might assume that the switch to https has *nothing to do* with the problem).

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Fred Marshall
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I should add that the behavior on the "broken" system is identical to behavior I see on a computer that doesn't have the VPN installed / running / connected.

I can access all the same pages from another, unrelated computer *and* I cannot access the *same* pages on the computer with the VPN client installed. This suggests there's something broken with the VPN configuration on the target client computer.


Reply to
Fred Marshall

Did you get your issue resolved?

Packets will use an interface based on the routing table. (type 'route print' at a command prompt) Generally speaking when the VPN is connected it will add a route to the table. So say your local LAN is 192.168.1.X/ and the Corp office is 10.1.x.x/ There should be a route added in the table that tells the packets to use the VPN interface for any packet destined to the 10.1.x.x network.

Now the VPN termination point might also be blocking ports and only allowing specific ports. You will have to be sure that the ports you are working with (80, 443) are both open for the VPN Clients.

I always try to use IP addresses of the servers that I'm testing with so I don't have to deal with name server issues at the same time. Once the IP Traffic is working well, then deal with how the names are resolved.

Name resolution is a unique issue with VPNs too. If you access

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without a VPN Connection. it uses your Public interface and DNS Server to get the address if it exists. If the name is also on the internal network DNS then it will have 2 addresses, the public IP and the Private IP. So now you bring up your VPN and try to access the same server... Well your machine already resolved the address to the public IP and will use that IP and not the internal IP. you will need to have it flush the DNS Cache resolver (ipconfig /flushdns) to clear out the old DNS entry and then query again. Even if you cant Ping the device (blocked ports or what have you) you can still ping the name to be sure that it resolves to the proper address

ScottI should add that the behavior on the "broken" system is identical to

Reply to
Scott Townsend


Thanks. I did resolve it by reinstalling the VPN client. Your description of how things work is helpful!


I don't know why I didn't see your post until today.... ?

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