Hello, I'm running Squid Cache: Version 3.0.STABLE13 with ntlm auth, using samba-3.2.10 and winbind, also SquidGuard 1.4 We are going to improve our structure with "load balancing" + "hight availability" with two servers running squid and a proxy.pac file (I would preffer to do this with LVS + Heartbeat, but at the moment the accepted solution is this). In this proxy.pac one subnet will go trought proxy1 and the other trought proxy2, but when one of the proxies go down the file will redirect to the other. I´ve read about an Internet Explorer issue with this configuration: In the PAC file, it is perfectly valid to return back multiple proxy servers in the return. The browser will first try to use the first proxy and, should it timeout or appear to fail, retry the query on the second and then third and so on. Again, this sounds relatively harmless but Internet Explorer interprets "timeout" very loosely. Experience has shown that if a user tries to access a WEB PAGE that doesn’t respond back in a timely manner IE will decide that it is the result of a proxy timeout and start sending requests to the secondary proxy. Needless to say, if your proxies are geographically dispersed this can start to spray traffic all across the WAN. This could be potentially mitigated by doing very careful tuning with proxy and Internet Explorer timeouts. I would like to know if is any parameter in the squid conf to prevent this to occur, or any way to make I.E. understand that the timeout comes from the url and not from the proxy Thanks a lot Gontzal