Scanning for ports in use

[Juergen Schmidt <ju () ct heise de>]

Hello,

has anybody ever tried, if there is a way to distinguish between ports
currently in use (not listening, but for example as local port for an
active telnet session) and unused port numbers. For example, do they
react differently to "strange" packets ?

bye, ju

-- 
Juergen Schmidt   Redakteur/editor  c't magazin
Verlag Heinz Heise GmbH & Co KG, Helstorferstr. 7, D-30625 Hannover
EMail: ju () ct heise de - Tel.: +49 511 5352 300 - FAX: +49 511 5352 417