Re: cannot connect to http server

Markus Heinz <su1690@studserver.uni-dortmund.de> wrote:

> I have a real strange problem. I cannot connect using linux to the http
> server where my homepage is hosted anymore. Since last week everything
> was fine. But now it only works a very few times. When I try to access
> it using Windows XP and Internet Explorer from the same computer, it
> works reliably. [...]

FYI, I also can't access your home page. I'm using a 2.4.20
kernel.


> Test 1: I have accessed http://home.arcor.de/markusheinz/index.html with
> Internet Explorer on Windows XP. It has worked like expected.
>
> Test 2: I have accessed http://home.arcor.de/markusheinz/index.html with
> Konquerer (KDE 3.1.4) and linux 2.6.1 from a Knoppix CD (Knoppix c't
> edition 3.4). The browser said "Waiting for home.arcor.de..." and
> nothing happened. After a long time it showed a "Connection timed out".
> The ethereal dump shows that it did not even send out a http request.
> Instead it sent four TCP packets with ACK and an old sequence number.

The TCP stack on the webserver home.acror.de appears to be broken.
It advertises a window of 0 bytes in the first place and then
neither answers the window probes / keepalives from the Linux box
nor sends autonomously a window update.

It looks like the webserver only answers window probes having the
expected SEQ and containing one byte of data. However it also
needs to answer segments having the expected SEQ - 1 containing
no data (aka. TCP keepalive segments).


> Has anybody an idea what is causing this strange behaviour and how I can
> fix it?

Talk to your provider (and have fun by explaining this to the
first level support). You could also try to post your problem
to a provider internal news group and asking for advice. Often
the tech folks have a look to these news groups and might help
you out. So you would spare yourself the hassel with first level
support. ;-)


Ciao, Horst
--
»When pings go wrong (It hurts me too)« E.Clapton/E.James/P.Tscharn