Just installed tcpspy and syslog-ng in grml-medium and worked like expected.
It works for me and i'll close the topic.

If you have any further details just reopen it.

Bypassing syslog by not detaching from terminal(option -d),
it is silent while there is traffic or segfaults.

With various traffic:
tcpspy -d -p                                            : no output
tcpspy -e ' not raddr 195.210.91.83' -d         : no output 

tcpspy -e ' raddr 195.210.91.83' -d
other tty:   telnet 195.210.91.83 80        -----> tcpspy segfaults

* zot <bts@bts.grml.org> [20080223 18:30]:

> tcpspy logging with syslog-ng doesn't output nothing.
> With debug option it segfaults.

So logging with sysklogd instead of syslog-ng works for you?
What's the exact command line you are exeuting?

regards,
-mika-

tcpspy logging with syslog-ng doesn't output nothing.
With debug option it segfaults.