Posting to one specific nntp server hangs emacs/gnus

[Tassilo Horn <tassilo@member.fsf.org>]

Hi all,

I use several nntp servers in gnus, for example Gmane and the news
server of my university.  But out of sudden, I have problems with
posting to groups of my university's server.  When I hit `C-c C-c' to
send away the posting, I get the message

  Sending...
  Sending news via Uni using nntp...

and then emacs/gnus hangs forever.  I have to hit `C-g' several times to
make it responsive again.  The posting is sent away anyway and appears
in the newsgroup.

It seems to me that gnus is waiting for some success message coming from
the server, which is not sent by that...

The *nntp-log* buffer has these contents:

--8<---------------cut here---------------start------------->8---
20100706T134611.673 news.uni-koblenz.de POST
20100706T134619.956 news.uni-koblenz.de QUIT
--8<---------------cut here---------------end--------------->8---

Well, not to helpful.

Telnetting to the server shows these information:

--8<---------------cut here---------------start------------->8---
% telnet news.uni-koblenz.de 119
Trying 141.26.64.5...
Connected to news.uni-koblenz.de.
Escape character is '^]'.
200 cache.uni-koblenz.de InterNetNews NNRP server INN 2.4.2 ready
(posting ok).
--8<---------------cut here---------------end--------------->8---

I use the gnus version that is included in the bzr trunk of emacs:

GNU Emacs 24.0.50.1 (x86_64-pc-linux-gnu, GTK+ Version 2.20.1) of
2010-07-05 on thinkpad

What might be the culprit?  How can I debug that any further?

Bye,
Tassilo