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In the last three month I was experiencing that my internet connection started to get very slow and websites had long time to load. The first thing I made was an ping to www.google.com which showed that I was loosing pakets. Here some of the results:

64 bytes from 74.125.39.103: icmp_seq=2909 ttl=53 time=48.222 ms
Request timeout for icmp_seq 2910
Request timeout for icmp_seq 2911
64 bytes from 74.125.39.103: icmp_seq=2912 ttl=53 time=44.372 ms

Days later I had to reset my router because it wasn't able to establish a correct network connection. It was after the reset when things worked again for some days. But later the same network timeouts started to happen again.

I would like to know how I can analyze the problem to get to the source which is causing this timeouts. Which steps do you take to circle in this Problem?

My Network
Laptop -> Wireless Router modem -> ISP

EDIT: I am on a Mac OS X 10.6

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what operating system are you running? if windows then download from microsoft netmon 3.4. And if you really want to get crazy download from microsoft research the tcp analyzer application. My best guess is the wifi router is going bad. –  tony roth Jul 1 '10 at 21:36
    
@tony roth I editet the question to give more information –  elhombre Jul 1 '10 at 21:55
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5 Answers

up vote 1 down vote accepted

Call your ISP. They can be surprisingly helpful.

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I gave up and thought I would never ever solve this problem until I called my ISP. First IT supporter said that the connection worked fine on their side, when I called again I got connected to an older electrician who said the same thing but also noted that I should check my telephone plugs if they have the filter connected on top of them because there was a constant noise in the background of our conversation. Well it appeared that a newly bought telephone in my house hadn't got a DSL filter (splitter) on top of it and every time when the telephone was in use the Internet would get cut off. –  elhombre Dec 15 '11 at 17:55
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Use traceroute (tracert in windows) against Google. This effectively gives you the latency to each hop between you and Google, and will give you an idea if it is your router, or further upstream.

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Look at using mtr on your OSX system.

It is very helpful tool that repeatedly does a traceroute, storing the information about each hop along the way.

So, in the end, you have a list of the "x" number of hops, their availability/packet loss and average, min, and max ping times.

Syntax for "interactive" mode is simply

mtr <site>   

or for easier offline analysis,

mtr <site> --report -c 1000

You can get info on how to install mtr from: http://mtr.darwinports.com

Sample output:

$ mtr google.com --report -c 10
HOST: blahblahblah                Loss%   Snt   Last   Avg  Best  Wrst StDev
  1. h119.127.19.98.static.ip.win  0.0%    10    5.4  14.4   2.0 111.1  34.0
  2. h235.30.213.151.static.ip.wi  0.0%    10    3.4   3.7   2.0   8.4   1.9
  3. h122.222.90.75.static.ip.win  0.0%    10    3.3   4.0   3.3   5.7   1.0
  4. h18.222.90.75.static.ip.wind  0.0%    10    3.9   4.5   3.4   5.5   0.7
  5. h16.222.90.75.static.ip.wind  0.0%    10    5.1   6.1   5.1   7.5   0.8
  6. h38.254.213.151.static.ip.wi  0.0%    10    6.7   7.3   6.2   8.8   0.9
  7. h14.254.213.151.static.ip.wi  0.0%    10   23.9  25.0  23.4  31.1   2.4
  8. h12.254.213.151.static.ip.wi  0.0%    10   23.9  24.8  23.3  27.3   1.1
  9. h10.254.213.151.static.ip.wi  0.0%    10   41.5  42.0  41.3  43.4   0.7
 10. 72.14.219.192                 0.0%    10   41.0  46.6  40.8  88.3  14.7
 11. 72.14.233.54                  0.0%    10   42.9  54.3  41.3 157.1  36.2
 12. 72.14.232.213                 0.0%    10   44.5  42.8  41.3  45.3   1.4
 13. 209.85.253.141               40.0%    10   50.5  51.4  48.6  55.8   2.5
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We where having problems with out of our Comcast business connections to a small site. Comcast was not very helpful when we contacted them because we didn't have data. Showing the problem.

So we setup a instance of smokeping and set it up to something on the comcast network a few hops away. We showed the smokeping graph to Comcast which was pretty consistently showing 10-15% packet loss. They tried lots of things, but eventually they discovered the wire between the poll and the building was bad. The point here is that you may need to collect a lot of data over time and graph it. A simple trace route may not be enough. Particularly if the issue is intermittent.

Of course please start off by doing the obvious and watch your connection to make sure you don't have any malware or crap on your machine that is saturating the link.

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First off, use a traceroute. Assuming you're using Windows, it's tracert www.google.com.

You may have to do several, but it will show how far your packets are going before they fail to get a response.

There's a good chance that you're going to have intermittent packet loss, which makes troubleshooting a massive PITA. It may help to A) Try your laptop connected directly to the cable modem, B) try a wired interface on your router, and C) try a different network entirely.

This helps determine if its your router (A), WiFi (B), or ISP/Cable Modem (C).

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