You have no permission to talk

[tschaggelar at ibrtses.com]

After a lengthy installation I was able to start INN. On the other side,
a news client (Thunderbird). I tried to refresh the list of available
newsgroups and got :  Error (NNTP). you have no permission to talk.
I immediately checked whether I started INN with user=root or
user=news. It possibly was root but I restarted as user=news. Also
the relevant directories appeared to be owned by user=news.
The FAQ didn't describe this error, but I somewhere else on the net I
found that the observed error was due to a slightly misconfigured INN.
I'm somewhat lacking the debugging tools. The error logs were empty
and /var/log/messages didn't show anything unusual.
What are the proposed debug tools in such a case ? tcpdump ?

rene