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I have a network with a really high ping (usually more than 500ms) except for one laptop. And in that laptop the ping is usually 5ms.

I've tried: - using same model laptop - compare lan driver version - test on another cable/docking station - compare gateway, submask, etc. - enter with other user in the pc (the users are in a win server 2003 active directory) - run with all the other devices disconnected from the network. - disconnected the WIFI from the "fast" laptop so there is no chance to catch wifi networks. - compared with spiceworks and found no big differences. (Almost the same apps and fixes)

I do not have access to the router config and firewall. But that has been tested and nothing was found. And there is the laptop working through the same network/firewall.

What am I missing here? Help is really really appreciated.

Thank you in advance.

Im using speedtest.net to test. Basically the internet is slow and the problem seems to be the ping. There is switching involved. Although I do have limited access to almost all devices.

Artur Carvalho
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    Pinging to where? – joeqwerty May 27 '11 at 15:07
  • In addition to joeqwerty's comment: Is there switching involved? What did the administrator running the router/firewall say? Does the problem follow the laptop or the port it's connected to? What happens if you give the "good" laptop's IP to another one? – Hyppy May 27 '11 at 15:11
  • Try pinging to the device at the furthest edge of your network (firewall or router) to see if you have the same results. If so, then it's an internal problem. If not, it's external and it's not likely you can do anything other than report it to your ISP. – joeqwerty May 27 '11 at 15:29
  • @Hyppy Using now the ip of good laptop, same thing, 500ms ping. The admin said everything was OK. – Artur Carvalho May 27 '11 at 15:32
  • @joeqwerty I updated the question, ping test with speedtest.net. – Artur Carvalho May 27 '11 at 15:33
  • @joeqwerty The ping to the router/firewall are fast. But how can it be fast in just one specific machine? Shouldn't it be a configuration problem in the machines? – Artur Carvalho May 27 '11 at 15:42
  • Is the ping to the router/firewall fast for all machines or only the one? If it's just the one then do the others maybe go through a proxy of some sort? – joeqwerty May 27 '11 at 15:54
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    Run a tracert from the good machine and a bad machine to www.speedtest.net and see if the path is the same. In addition, this is a longshot, but run a packet capture on the good machine and a bad one and run your speed test. Look for any ICMP redirects in the capture on the bad machine. If you see any on the bad machine but not the good machine then that's an indication that the traffic on the bad machine is being re-routed through a different path. – joeqwerty May 27 '11 at 16:06
  • @joequerty They are all going through the same proxy, and the ping is fast to the router/firewall from any pc. – Artur Carvalho May 27 '11 at 16:07
  • @joequerty I get a "destination host unreachable" with tracert. I'm not able to turn off the firewall. (Thank you very much for the help! Really appreciate it) – Artur Carvalho May 27 '11 at 16:16
  • OK, then the problem is probably external. I'm able to tracert to www.speedtest.net so it's odd that you're getting that message. Try running a tracert to another external host (web or ip address) on both the good machine and a bad machine and see if anything is different between the two. – joeqwerty May 27 '11 at 16:22
  • @joequerty Fast laptop left. Will try the packet capture/tracert again Monday. Thank you very much! – Artur Carvalho May 27 '11 at 16:25
  • Go to your IT Manager/Director/CIO and show him the traceroutes, letting him know that the network guy refuses to help his sysadmin. This sounds like it's more of a political issue than a technical one. – Hyppy May 27 '11 at 16:26
  • @Artur: Glad to help. Keep us posted. – joeqwerty May 27 '11 at 16:27
  • @Hyppy Sometimes there is work overload for them and here in one PC the net is OK for some reason. So we have a lead now and trying to solve the problem with it. – Artur Carvalho May 27 '11 at 16:38
  • Have you checked TCP-no-delay patch on fast laptop ? It's also extremely reducing ping times. Leatrix latency fix is the famous. – risyasin May 27 '11 at 21:16
  • a ping of 500ms to anywhere is never OK.... (maybe mars). Get to a Command prompt and run IPconfig /all. Ping your gateway and let us know what that is. check the IP that each computer is showing in the lower left of the speedtest.net page. if that it different on the work or not working that could be a clue. I'm thinking that your admin turn off incoming pings on the internet side and 500MS might be the point speedtest.net gives up trying. I can ping new zealand with a 443MS nothing with in your state should be more then 30 to 70... – Christopher Thornton May 28 '11 at 00:39

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You might also want to use port mirroring on the switch to see if there is a crap ton of broadcasts happening.

Will
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