redirection but url not change on browser

As Nitass suggests, you could still transparently proxy requests to the second site even if it's not directly on an LTM subnet. LTM would need to have a route to the site. You'd want to rewrite the host header on requests as Naladar has shown and select a pool with the server(s) for the second site configured. If you need to dynamically look up the IP address(es) for the second site, you could do this with an iRule which calls RESOLV::lookup (http://devcentral.f5.com/wiki/default.aspx/iRules/resolv__lookup). You'd probably need to SNAT the serverside connection as well.

 

 

Aaron