Web Browser Stop Working after VPN Client Installation

Hi there,
I have a Cisco PIX515E server, and users are using Cicso VPN client version
4.x or 5.x. This system has been working fine.
But I suddenly got one weird problem on one user's laptop ...
This is an IBM/Lenovo ThinkPad laptop with Windows XP Pro. Once I installed
the Cisco VPN client, I could NOT access any web sites (either on Internet
or inside the corporate network) over http using any web browser (either IE
or Firefox).
But I could access https, or ftp, or any other port (e.g.
http://somesite.com:8080), which means only accessing port 80 becomes
disabled.
But as long as I get the VPN connected, I can access everything.
Once I uninstall the VPN client, it is back to normal.

Any idea would be appreciated,
Ross

 

I don't know any specific problems that fit your description but I can
think of some things to check.

Computer may have spyware or a trojan that is attempting to intercept
all HTTP traffic.

There may be another VPN or security product installed that is scanning
HTTP traffic but is incompatible with the Cisco VPN client.

I don't use Cisco VPN products so I don't know what kind of policies you
can apply to the client side but it's possible there is a Cisco VPN
configuration problem somewhere.

You may have some kind of proxy setting or proxy client installed. You
may have TCPIP filtering in the advanced settings of your network
adapter with some filter settings or it may be set with a group policy.

 

The VPN client has a stateful firewall, and there is a setting for "stateful
firewall always on", uncheck this box.