I have a vpn network with 4 sites, 4 cisco routers and i used Ipsec with preshare keys. I would like to redirect all Internet traffic of sites to a central site that will route it to an ISA server that will check the traffic. the vpn is already setup but i don't know how to redirectt ip packets on an interface by identifing the source address IP of the packet?
if you are only concerned about clients using vpn traffic, what you could do is set all IE or firefox browsers (this can be automated) to use a proxy for internet access. The routers would only allow the ipsec traffic and not clients directly going over the internet.
Each client would send their web requests to the proxy (proxy should have a private ip address) and as long as you have the internal routing between offices working correctly they will route to the proxy server ISA.
hope this helps,
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