[VOIPSEC] TLS and Firewalls

[Volker Tanger]

Greetings!

On Tue, 08 Feb 2005 18:25:04 +0100
"Thorsten Brinkmann" <mail at Thorsten-Brinkmann.de> wrote:

> securing VoIP (e.g. SIP) with TLS is a nice idea. But how can
> firewalls handle this? Look at the workarounds are needed to use HTTPS
> thru firewalls. 

Not at all - the RTP part is the complicated one, opening two completely
independen UDP streams in both directions, usually without any
connection to the SIP session.

The SIP session usually is done between client and gateway/server or the
two gates/servers. After signaling RTP gues between the clients doing
the audio transfer.

And for handling that the firewall *MUST* be able to look into the SIP
or H.323 protocol. Which then is not to be encrypted. So no TLS if you
want the audio stream too and not just the"ringing/busy/okay"-messaging,
sorry.

Bye

Volker

-- 

Volker Tanger    http://www.wyae.de/volker.tanger/
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