three-way TCP

[Sébastien Cantos]

Hi,

You can check if a service (tcp port) is responding just by completing 2
parts of the 3 way handshake.

1/ Client send a Syn to the server
2/ Server respond with a Syn/Ack

This is called *stealh* scanning.

Regards,
--
Sébastien Cantos <scantos at technodiva.com>
Responsable réseau et systèmes 
Neopost DIVA 

> -----Message d'origine-----
> De : nagios-users-admin at lists.sourceforge.net 
> [mailto:nagios-users-admin at lists.sourceforge.net] De la part 
> de Jason Martin
> Envoyé : jeudi 7 octobre 2004 16:45
> À : nagios-users at lists.sourceforge.net
> Objet : Re: [Nagios-users] three-way TCP
> 
> On Thu, Oct 07, 2004 at 04:00:01PM +0200, Andreas Ericsson wrote:
> > jon quidilla wrote:
> > >I just need verify if nagios is using a three-way TCP
> > >protocol in services such as http.
> > Yes. It's fairly easy to sniff out using strace. Look for 
> the argument 
> > to connect() and match it against the later close()'s calls 
> arguments. 
> > The kernel takes care of sending FIN and friends from there on.
> I don't see how nagios would be able to check any TCP service
> w/o doing the usual 3-way handshake; what are you seeing that
> brings up the question?
> 
> -Jason Martin
> -- 
> Useless Invention: Kickstand for a tank.
> This message is PGP/MIME signed.
> 



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