Joe Abley jabley at isc.org
Sat Nov 1 18:23:15 UTC 2003

On 1 Nov 2003, at 12:43, Owen DeLong wrote:

> That probably means they are not using SIP, but, instead are using
> either H.323 or some other proprietary ugliness.  That's unfortunate.

You can use SIP through a NAT, if you can hack the NAT to poke 
particular ranges of ports back to devices on the internal network.

There's no useful way to use H.323 through a NAT though, at least that 
I have seen working.

> SIP has to include the IP address of the RTP destination in it's 
> payload.
> As such, you can't use SIP cleanly across NAT unless the NAT box knows
> to proxy the SIP and edit the payload (very messy).

Yeah, that's not actually the case.


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