Hi,
I know that IAX also works between networks using NAT, but SIP or H.323
doesn't. I wonder what is the reason for this behavior? Is there a
difference between this protocols acccording to NAT?
Thanks in advance!
Holger
--
Holger Schildt <mail@HSchildt.de>
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VoIP protocols normally use 2 connection: * 1 for control (eg on port 5060 for sip) * 1 for the RTP (media stream) The latter hasn't a fixed port, since is negotiated by the control connection. That could cause some troubles with NAT & firewalls. IAX doesn't use 2 ports, but only one . So on the same port it brings the control connection & the RTP stream. So NATting IAX isn't a problem Matteo. Il sab, 2003-09-27 alle 11:46, Holger Schildt ha scritto:> Hi, > > I know that IAX also works between networks using NAT, but SIP or H.323 > doesn't. I wonder what is the reason for this behavior? Is there a > difference between this protocols acccording to NAT? > > > Thanks in advance! > Holger-- Brancaleoni Matteo <mbrancaleoni@espia.it> Espia - Emmegi Srl
Holger Schildt wrote:>I know that IAX also works between networks using NAT, but SIP or H.323 >doesn't. I wonder what is the reason for this behavior? Is there a >difference between this protocols acccording to NAT? > >IAX uses a single raw UDP socket for all calls. Since there is no RTP, the IP address is not embedded in the protocol itself so as long as the UDP packets show up at the right spot (port forward) everything just magicly works. Jeremy McNamara