05-30-2006, 03:37 AM
Both from work and from home, run traceroute against some of the slow sites. (OS-specific note: on Microsoft Windows systems, this utility is misnamed tracert.) Compare the output, looking for any obviously slow hops. Anything greater than 1 second is usually considered unacceptable / a sign of problems. The slowest hop between me and the Lounge is ~200ms at present. In its standard operation, traceroute should provide you with three numbers for each host in the route, corresponding to the responses for each of three probes it sent to that host. If a response is not returned, traceroute places a * in that position. If you see many stars, that's a bad sign (high packet loss). If you see all stars, it means the packets traceroute needs for correct operation are being disallowed, so you cannot measure responsiveness at all. That's very bad from a network diagnostics perspective, but does not say anything specifically about the problem you observed. When a packet is lost, it must be retransmitted. To avoid flooding the network, there is a delay before retransmission occurs. If you are losing many packets, that translates into many delays before the remote host finally receives all your traffic.
From work and from home, look up the IP addresses of various slow sites. Both places should show the same result for a given site, assuming enough trials. (Some places, like Google, have many IP addresses. It could take a while to find all of them. Therefore, you should prefer looking up places like the Lounge, which have very few IP addresses.) If the results differ, it's likely that, as Flymo suggested, you have some sort of infection. You may also wish to consider anti-spyware utilities such as Spybot: Search&Destroy and Ad-aware.
How stable are you in UDP based games? Such games (e.g. Diablo 1, Starcraft, or Warcraft II: BNE, but not Diablo II, Warcraft III, or World of Warcraft) are very sensitive to a lossy connection. High packet loss will usually make the games unpleasant, if they are playable at all.
You may also want to try downloading a large file over http or ftp, to rule out protocol-specific traffic shaping as a culprit. This seems less likely since you said some web sites are slow, but if nothing else turns up, you could try this. I recommend downloading a copy of the Linux kernel or a Linux LiveCD distribution (such as Hakin9), since they are large and legal downloads. As a bonus, if you grab Hakin9, you could burn it to a CD and reboot into it to test whether the problem is in your modem or your system. If Hakin9 comes up and you get good performance in it, but poor performance on your normal desktop OS, it is a problem with your system. Since it is a LiveCD, you can use Hakin9 without erasing your existing Windows installation. Just don't try to write to your Windows filesystem(s) from Hakin9.;)
From work and from home, look up the IP addresses of various slow sites. Both places should show the same result for a given site, assuming enough trials. (Some places, like Google, have many IP addresses. It could take a while to find all of them. Therefore, you should prefer looking up places like the Lounge, which have very few IP addresses.) If the results differ, it's likely that, as Flymo suggested, you have some sort of infection. You may also wish to consider anti-spyware utilities such as Spybot: Search&Destroy and Ad-aware.
How stable are you in UDP based games? Such games (e.g. Diablo 1, Starcraft, or Warcraft II: BNE, but not Diablo II, Warcraft III, or World of Warcraft) are very sensitive to a lossy connection. High packet loss will usually make the games unpleasant, if they are playable at all.
You may also want to try downloading a large file over http or ftp, to rule out protocol-specific traffic shaping as a culprit. This seems less likely since you said some web sites are slow, but if nothing else turns up, you could try this. I recommend downloading a copy of the Linux kernel or a Linux LiveCD distribution (such as Hakin9), since they are large and legal downloads. As a bonus, if you grab Hakin9, you could burn it to a CD and reboot into it to test whether the problem is in your modem or your system. If Hakin9 comes up and you get good performance in it, but poor performance on your normal desktop OS, it is a problem with your system. Since it is a LiveCD, you can use Hakin9 without erasing your existing Windows installation. Just don't try to write to your Windows filesystem(s) from Hakin9.;)