Hilfe & Kontakt

SIP over double NAT headaches

Von: Theo Markettos (theom+news@chiark.greenend.org.uk) [Profil]
Datum: 21.04.2010 17:43
Message-ID: <uVb*jD88s@news.chiark.greenend.org.uk>
Newsgroup: uk.telecom.voip
I have the following setup:

192.168.1.*: IP phone (not bought yet, using a laptop for the moment)
| Local side of consumer router (Huawei B220)
Linux NAT
PPP over mobile broadband 3G/HSDPA connection
10.*.*.*: Mobile network (MTN Sudan)
Carrier's NAT (might be symmetric NAT)
| Internet

I can set up port forwards on the router as much as the crummy router
software allows (it runs Linux, but installing OpenWRT etc isn't an option
nor is changing the router).  But I'm still stuck with the carrier's NAT.

Is there any way I can push SIP into working over this setup?  For example,
will STUN work with additional port forwards?  One problem is that I can't
be sure of what the public IP will be to embed into the SIP packets.

One option is to use UPnP, if the carrier NAT supports that (which I doubt).
But I suspect the relevant multicast packets won't get that far.

I've just tried another network (Zain Sudan) which is also using NAT on the
'Internet' APN.  I've seen SIP successfully working on Zain mobile
broadband, so it must be possible.  Perhaps there's an APN that gives a
global IP, but these sort of details just aren't available (and techsupport
doesn't exist).

Or should I give up and use Skype, which works?  But wish me luck trying to
find a Skype hardware phone in Sudan.


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