[Openswan Users] Weird problem with Internet Explorer proxy settings when using VPN

[Albert Strasheim]

Hello all

This message is more about Internet Explorer on Windows XP SP2 in 
the presence of a VPN connection than about Openswan, but I think it 
might be of interest to the community.

I recently set up a VPN between a Fedora Core 4 system and Windows XP 
SP2 using Openswan 2.4.2dr1 and l2tpd 0.69.

"Use default gateway on remote network" was turned off in the VPN 
connection's TCP/IP settings. This was confirmed with a route print in 
the Command Prompt. IE was set up to use an autoconfiguration script 
(PAC) in Tools | Options | Connections | LAN Settings. The PAC script 
tells IE to access various hosts on the local network directly and to 
use the network's proxy server for anything else.

As this stage, traceroute, ping and direct connections to port 80 using 
telnet worked for all hosts on the local network. Connections to other 
hosts through the proxy server worked. However, when the VPN connection 
was on, connections to some local network hosts with Internet Explorer 
didn't work. Directly connecting to port 80 still worked fine.

Then I changed the VPN connection's proxy settings to match the 
global IE settings in Tools | Options | Connections | <select VPN 
connection> | Settings.... Suddenly, I could access all the hosts on 
the local network again.

The same problem might occur when using a normal proxy server while 
telling IE to not proxy connections to local hosts, but I haven't 
tested this.

Cheers

Albert