On Wed, 3 Feb 2010 21:32:48 +0200, Dave Coventry <dgcoventry@xxxxxxxxx> wrote: > Hi, > > 2 of my users access my server through the same ISP who (I presume) uses > Squid. > > Sometimes the browser connects with no problem, but both of these > users have sporadic occurrences of the browser stalling. (It just says > 'Loading' but never loads) > > My Server runs from our office but the National Telcoms Provider does > not believe in static IPs, (we are in South Africa) therefore we have > to run a Dyndns account to keep track of our IP. Static IPs are expensive these days with IPv4 numbers running out. > > My theory is that the Clients' ISP is caching our content and causing the > stall. > > Rebooting the Server's ADSL modem/router allows both of these users to > re-access the server and my theory is that the change of IP address > after the reboot bypasses the clients' ISP's cache. > > What I would like to know is if there is any way for the clients to > clear the cache? Not the browser cache, but the squid cache on the > ISP's machine. > > Alternatively, if you feel that my theory is a pile of horse, could > you suggest what else might be happening? It's one pile of horse amongst several. Any of which might be real hay. I'm more inclined to think some intermediary is having persistent TCP connection problems. Caching the content will at worst result in old dead content being served back to the clients. But still served back. Restarting the server indicates some active connection is hung. The quick way from the client end to refresh intermediary caches is Ctrl+Reload or Shift+Ctrl+Reload (reload being the reload or refresh button on the browser GUI, on windows Ctrl+F5 also works apparently). I'm not certain but it might work for client connections as well. This will only work if the middle proxies are HTTP standards compliant. The bad news is that due to many broken websites and browsers over the years, ... website gives broken/short cache-controls causing excess bandwidth -> admin disable cache controls compliance in proxy -> clients start getting bad content -> clients use cache-refresh far more often -> admin notices rise in bandwidth from client refreshes -> admin disables client refresh logic compliance. -> website admin notice bad content -> reduce cache controls even further ... Internet goes badly for everyone. Amos
