I have an ADSL connection at home. Pings times are usually acceptable right after rebooting the modem, between 15 and 60ms to google.com. A few minutes later they go up to 900ms or even higher up to 3 to 4 seconds. There is only one phone plug in the house with the ADSL modem connected. Nothing else uses that line. I asked my ISP about this for several times and all they can come up with is the dreaded "did you turn it on and off" response.

Problem: Internet surfing becomes horribly slow, watching video's is out of the question.

Diagnosing: Running ping (with and without -n to bypass DNS lookups) to google.com from the modem.

What I tried:

  • changed the ADSL splitter
  • bought a new ADSL modem
  • changed the ADSL cable between the modem and phone plug
  • checked down and upstream rates (modem says 8708 Kbps down and 1037 Kbps up, exactly what my ISP sees)
  • changed from my ISP's DNS servers to Google's public DNS servers

A small sample:

PING google.com ( 56 data bytes
64 bytes from icmp_seq=0 ttl=51 time=16.792 ms

3 minutes later, nothing changed:

PING google.com ( 32 data bytes
32 bytes from icmp_seq=0 ttl=52 time=2417.5 ms

Anybody has some pointers on what I should try next? Changing my ISP is probably one possibility...

  • 1
    you do not mention if you are using a switch/router. Are you connected directly to the modem? if not, have you tried that? – Logman Mar 2 '13 at 14:14
  • Thanks Logman, it's a modem/router in one. I run the ping tool FROM the modem/router to make sure the problem is not on my internal network. – Cimm Mar 2 '13 at 14:16
  • have you tried reseting modem/router? turn off, unplug everything, hit the reset button on modem/router? Have you tried a different phone jack? or even go to the junction box (where it comes into the house? – Logman Mar 2 '13 at 15:45
  • Logman, it's even a new modem, different hardware, so yes I did reset everything. The different phone jack is an idea but there is only one in the house. Haven't tried the junction box, will try that. – Cimm Mar 2 '13 at 16:06
  • Check your startup programmes. You may find there are a lot of updaters messing up your ping times – Tog Mar 20 '13 at 13:54

Is this isolated to just one computer? If yes, I wonder if you might have some file share or torrent server installed (either knowingly or rogue software unknowingly) on your computer, and as soon as your machine comes online someone (or something) is connecting to your machine and using up all of your bandwidth. Look at the bandwidth you're using in the OS while this is happening to see if it's higher than it should be from just sending the results of the ping back to you. (However method it does- web browser?)

If the Modem can keep the ping going without your computer connected, Shut down your computer for a few minutes, come back and see if the ping times went back to normal while your computer wasn't connected.

  • 1
    Thanks a lot, I now think it is my backup application that kicks in. I should be limited but it looks like it might not play by the rules. This would explain why the ping time is low when the modem just restarted, the backup application thinks the connection is still down so isn't uploading. After a few minutes it kicks in. – Cimm Mar 2 '13 at 21:34
  • Thanks, in my specific case it was my phone (Google+ auto backup feature). – wil93 Aug 31 '14 at 1:21

Definitely try pinging a more local service by IP address rather than name - bbc.co.uk is a good one for the UK. Also make sure that nothing is connected to the router (unplug all of the LAN cables) when you test. If you are still getting a problem, contact your ISP.

If you are in the UK connected to a BT line, unplug the router from the phone line, remove the cover from the MASTER plate which is where the line enters the house, inside there is a TEST socket - connect to that and rerun the test. Again, if you are still getting the problem, contact your ISP.

  • Thanks Julian. I'am in Belgium and guessed Google would not resolve to the US servers, guess they have some servers closer to home. But, thanks it's a good tip, will use our national broadcaster's domain to test. – Cimm Mar 2 '13 at 19:19

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