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Re: ideas for diagnosing connection problems?

From: Daniel Stenberg <daniel_at_haxx.se>
Date: Thu, 21 Nov 2002 08:41:02 +0100 (MET)

On Wed, 20 Nov 2002, Dan Wood wrote:

> I have a *few* users of my app which I have just updated to use libcurl
> 7.10.1 and they are consistently getting "* Empty reply from server*" and
> "* Couldn't resolve host 'www.tvguide.com'"(several well-known sites,
> actually) in my application.

Are the same users getting both errors or are different users getting
different errrors?

I find these two errors quite different in nature and whatever is causing
them, it seems unlikely that this is one single reason.

Of course, a "quick" test could be to update again to 7.10.2 and see if the
problems are still like this.

> And yet, they are able to connect to the sites from their Web browser,
> which leads me to believe that something is wrong with libcurl.

It certainly sounds like that, yes.

> Or maybe the problems are just a coincidence. I have made a little test
> application for them that connects to the problematic sites using the
> "verbose" mode, so I am getting some information in stdout -- but nothing
> that really gives me any indication of why they can't reach these sites.

Are they all using this application pre-built binary by you? If so, are you
building libcurl with IPv6 support or not? If not, how many arguments does
your gethostbyname_r() take? (The source code doesn't currently mention this
for Mac OS X.)

Are the users who get the fails using any particular version of Mac OS X or
are they using various versions? (I mean, if there's a risk of any subtle
differences in the name resolving function or similar.)

> Any suggestions on what can be done to try on *their* machines that would
> help me find out where the problem lies?

I just want to first narrow down exactly what name resolving code that is
used, read the code for that part and then suggest a route on how to trace
this down.

-- 
 Daniel Stenberg -- curl, cURL, Curl, CURL. Groks URLs.
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Received on 2002-11-21