I have two network cards. If I connect to a network using VPN then to access other websites I have to pass through a proxy server.
Is it possible to use my other network card to connect to the Internet directly without passing through the proxy?
What you are asking is called "Split DNS" or "Split Tunneling". The VPN appliance must support this OR you can manually enter the IP address and hostname information into your hosts file.
The information that the Cisco VPN client is used wasn't in the original post, and it basically changes everything and much complicates any final solution.
The biggest problem is that the VPN server must have been configured to allow split tunneling. Otherwise, it just sandbags you in your computer.
Second, you can attempt to configure according to the Cisco article Configuring Cisco VPN Client 3.5 and the Cisco Integrated Client to Secure Nonencrypted Traffic While Using Split Tunneling.
However, I can recommend from my experience one solution that solves the problem without any additional configuration. This solution is simply to install and call the Cisco VPN client from a virtual machine. Even if the Cisco client then attempts to sandbag you in, it will only sandbag the virtual machine, rather than your computer. Your own computer stays free and able to use the Internet, while the VPN is used from the virtual machine.
The Cisco VPN client creates a tunnel, which can be voluntary or compulsory. The type of the tunnel is dictated by the administrator of the VPN server to which you connect. The compulsory tunnel will cut off all access to any external computer, including the LAN, and is what I called the "sandbox".
For more information, see Compulsory Tunneling in the following articles.
If you wish to become an expert in everything VPN, a good book is most recommended, since there is just too much information.
Yes, it can be done, but depending on your current configuration the answer may vary. So I need some extra information: