[Freeswitch-users] Hostname vs IP in SDP

Colin Morelli colin.morelli at gmail.com
Wed Aug 3 17:53:09 MSD 2016

Interesting. So far it has worked on all clients except WebRTC. It seems
strange to me that putting a hostname in an SDP wouldn't be allowed, but
it's far from the weirdest thing I've seen in some these specs.

I'm fine with having IPs in the SDP for pretty much all cases, except for
the iPhone where it is supposedly necessary to not use IP literals. So I
guess I have two questions then:

1. Is there a way in FS to explicitly set an advertised IP address through
a channel var? Actually, in this case I would just define a few options in
vars.xml and then use expansion. Something like,
advertised_rtp_ip=${local_ipv4} or advertised_rtp_ip=${local_ipv6}

2. How are people deciding whether to advertise IPv4/IPv6 if FS
*isn't* handling
registrations. Say, for example, Kamailio handles registrations. FS only
knows if it'll talk to Kamailio via 4 or 6, but not what Kamailio will use
to talk to the clients. Is there a best practice here for supporting dual


On Wed, Aug 3, 2016 at 1:13 AM Michael Jerris <mike at jerris.com> wrote:

> I have not once in my life seen someone use a hostname instead of an ip in
> an sdp, and I do not believe it is legal.
> > On Aug 2, 2016, at 1:00 PM, Colin Morelli <colin.morelli at gmail.com>
> wrote:
> >
> > Hey all,
> >
> > So it looks like WebRTC has issues dealing with hostnames in the SDP
> instead of IP addresses. Particularly, when including a hostname in the SDP
> there's no audio in either direction. This is the case in both the latest
> Firefox + Chrome browsers.
> >
> > This is particularly problematic for applications that are WebRTC +
> mobile, now that Apple is enforcing applications to support IPv6-only
> networks. Using hostnames in the record-route and SDP addresses meets the
> requirement since the OS will synthesize an IPv6 address when a DNS query
> is performed, but according to the documentation they strongly urge
> applications to avoid using address literals in their applications.
> >
> > Has anyone had success with methods to switch between advertising a
> hostname vs IP address in the SDP? Or other methods for solving this
> problem?
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://confluence.freeswitch.org
> http://www.cluecon.com
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> http://www.freeswitch.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20160803/10e8d32f/attachment-0001.html 

Join us at ClueCon 2016 Aug 8-12, 2016
More information about the FreeSWITCH-users mailing list