iptrace?

[Markus Schönhaber]

Dotan Cohen wrote:

> Connecting to many websites (google.com, what-is-what.com,
> slashdot.org, yahoo.com) would be terribly slow, and often would time
> out. Some images would not load as well.

OK, it's obviously not a site-specific thing.

>> How about the most basic info, what *exactly* you did when the problem
>> occurred and what *exactly* happened. I still don't know that.
> 
> Typing, for example, "www.google.com" into my web browser's address
> bar. I would have to wait an exceptionally long time (30 seconds?)
> before seeing any type of response.

If, when that happens, you access the same site again, is this second
request answered faster or will take a long time again?

> The problem is intermittent, and
> not occurring now, but has been recurring for several days.

But is it reproducible in the sense that when it happens, it happens
more than once?

>> Useful info might be, for example:
>> - Which browser?
> 
> Firefox 3b5 and 3rc1, Opera 9.x, and Konqueror 3.5.9

Not browser-specific either.

>> - How is your machine connected to the internet? Directly? Otherwise
>> (how exactly)?
> 
> This Dell Inspiron laptop is connected via ethernet cable to a Level1
> router, which is connected to a cable modem, which is connected to out
> cable TV provider, which connects to the ISP.

Oh. Many components, many potential problem sources.

> Note that in my country,
> the only way to connect to the ISP is either via the cable company
> (cable modem) or the phone company ([a]dsl modem). We pay twice: both
> the cable company and the ISP get a check every month.

Gret stuff...

>> - What is the exact error message?
> 
> Standard http 502 error message for each browser in the event of
> timeout, or terribly slow connection in event of connection. This is
> intermittent, and not occurring now, but has been recurring for the
> past few days.

502? You said 504 before.
Anyway, since both messages are associated with a gateway or proxy, does
the message contain any hint which server issued it (if in doubt, copy
the message verbatim).

> What else? Kubuntu 8.04, wired connection, no firewall, known-good
> cabling (I have tested the cabling with a cable tester, and tried
> replacement cabling).

Another potential problem source excluded.

>> At least I am still not sure if I can be of any help with your problem.
> 
> If you can be, then it will be most appreciated. Especially if you
> visit Haifa and like beer :)

Hehe ;-)

>>> How about this page:
>>> http://dotancohen.com/images/examples/bezeq.html
>> Might be helpful - but can't say for sure because I don't know what you
>> did and why, when you took those screenshots.
> 
> I set mtr to work, with no other network applications running (no
> firefox, no bittorrent, no wget) and went to eat.

I'm not familiar with mtr. But two things catch my eye:
1. The "Resolver error"s on some of the shots.
2. The massive packet loss on some .bezequint.net machines.
Especially 2. may be a understandable cause for the symptoms you're seeing.
Which of the devices listed in the shots are in your home? Very likely
192.168.123.254. Are there more?
Especially if the machine before the machine which is shown with the
massive packet loss doesn't belong to your net, there's probably not
much you can do.
Clutching at straws: you could try to lower the MTU of your external
interface and see if that changes anything.

>> BTW: why didn't you simply copy and paste the command and it's output
>> but took those shots of the terminal window?
> 
> In Konsole I cannot simply copy the text of 'running' programs such as
> mtr and top. So I took the screenshot. Static terminal applications
> (apt-get, less, most everything else) I can copy.

Pressing Ctrl-S should freeze the output, enabling you to copy it.
Ctrl-Q resumes.

Regards
  mks