Chris G wrote:
I wasn't expecting an answer, just ideas to poke around with, your suggestion of traceroute is one such and, as I said, I'll dig further with that if it happens again.
Some other ideas:
Do things improve after a router restart? I've found that sometimes they get clogged up with too much traffic and get confused (I'd guess something to do with how they handle NAT but that would just be a guess). If restarting the router helps, look for firmware upgrades or a new router.
Do things get particularly bad in bad weather (rain/snow)? If your router shows you ADSL errors, check them and see if they're a problem for you. We find that our line isn't great when the weather is bad.
Is Google always instant? (Not iGoogle, if you use it.) Maybe you have an issue of MTU settings; sites like Google only send data in small packets that seem to always be instant but other sites with substantial content will get bogged down by fragmented packets. Try pinging sites with large packets (after confirming they respond to a normal ping). Eg: ping www.google.co.uk -s 1472 .. should work if your MTU is 1500 (ifconfig will tell you). Change -s to -l if you're testing in Windows (l for size? Yeah, Windows is easier than Linux!) For that matter, if you can test in Windows I'd recommend doing that to see where the problem lies. You can change your MTU temporarily for testing: sudo ifconfig eth0 mtu 1000 .. assuming eth0 is your ethernet port. You should get responses for packets anything up to 28byes less than MTU. If your MTU is too high, the packet will get fragmented by something between you and the site and is likely to cause problems.