I had the same problem , and i followed the suggestion from Antony stone that wrote: 3. Use your existing DNAT rule in the PREROUTING nat chain, but insert some rules before it which match a destination address using "-d a.b.c.d" and use the target "-j ACCEPT" so that these packets bypass the DNAT rule. I did more or less the same... i use this IPTABLES -t nat -A PREROUTING -i "myinterface" -p tcp -d ! xxx.xxx.xxx.xxx --dport 80 -j REDIRECT --to-port 3128 -v and now the request to the OWA is not passing to squid anymore. You need to have the IP address of the site using Outlook WebAccess. I don't know what it's exactly the problem with this service, and in the Microsoft Web page there's nothing... just a note about troubleshouting the OWA with the Microsoft Proxy, that basically has the same problems than with squid. I hope this helps, karina. Ryan Beisner wrote: > I don't know if anyone else has noticed, but SQUID doesn't treat some > websites very kindly in its http acceleration (transparent proxy). > Mainly, Microsoft Outlook Webmail (I have a client using it). > > [ BTW this is a strange breed of a web based mail system .. it looks > like you're using Outlook, within a webpage, released by MS. Their > firewall info claims that HTTP is the only protocol in use. ] > > I have already configured Squid not to cache that entire domain, and it > doesn't cache it. I've flushed the cache, then looked at the "All Cache > Objects" SQUID report, to find none at domain XYZZZ.COM. > > OK, so how would one turn this rule around into a couple of rules that > redirect port 80 to 3128, *unless* it's to/from "any-host.xyzzz.com" or > "any-host.anotherdomain.com" etc ? > > .......................}SNIP{........................... > $ipt -t nat -A PREROUTING -i $eth0 -p tcp --dport 80 -j REDIRECT > --to-port 3128 > .......................}SNIP{........................... > > I realize I could create a rule based on their IP range, but I want the > rule to be based on the domain name -- I haven't yet seen that in > action. ;} > > All help is appreciated! > > TIA > > -Ryan Beisner