[asterisk-users] Multi-homed SIP in Asterisk 11?

[Tony Mountifield]

In article <51F925F2.1040304 at dns99.co.uk>,
Gareth Blades <mailinglist+asterisk at dns99.co.uk> wrote:
> On 31/07/13 15:32, Tony Mountifield wrote:
> > Most of my experience until recently has been in Asterisk 1.2, and I am
> > just starting to make use of Asterisk 11 for new systems.
> >
> > I have a question about using SIP on a multi-homed machine.
> >
> > I have a customer who wants an Asterisk box with two network interfaces:
> > one on the public Internet (no NAT), and one on a private LAN. The box
> > will not do any IP forwarding between interfaces. They want to connect
> > to a SIP trunk from an ITSP via the public interface, and to have SIP
> > phones on their LAN registered via the private interface.
> >
> > I haven't tried such a setup before, so before creating a test system,
> > I wondered if anyone here has made such a setup, and whether there are
> > any issues with getting SDP contents and media routing correct?
> >
> > Cheers
> > Tony
> I normally just ensure localnet= and externip= is set correctly. I 
> normally also have 'directmedia=no' defined in sip.conf so that asterisk 
> is performing store and forward for all the rtp traffic. That does mean 
> rtp traffic for internal calls is going via asterisk where it could be 
> direct between the phones but the amount of traffic doing this is 
> normally pretty trivial so it doesnt matter in most cases.

Thanks. But I thought localnet= and externip= were for when the external
interface is going through NAT. In this case the ITSP is connected through
a real non-NATted public interface.

Is it possible to specify directmedia=no just for the SIP trunk? So that
the phones could still do direct media between themselves, but not if
they were connected to the trunk?

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org