[Freeswitch-users] Hostname vs IP in SDP

[Steven Ayre]

> more and more dual stack endpoint

Bear in mind that the SDP contains 'IN IP4' or 'IN IP6' to pick the IP
version so you aren't going to be a in position where they can pick at will
from A and AAAA records for your FQDN.

On 4 August 2016 at 13:25, Colin Morelli <colin.morelli at gmail.com> wrote:

> Hey Steven,
>
> I did check that as well. So far as I can tell, most of the shared
> portions of the SDP come from RFC 4566. The ICE additions in RFC 5245 also
> claim to allow FQDNs for candidate addresses.
>
> My assumption is that it's just not commonly used. But it seems much
> easier to support hostnames everywhere as more and more dual stack
> endpoints.
>
> Any thoughts on a per-channel advertised address?
>
> Best,
> Colin
>
> On Thu, Aug 4, 2016 at 8:14 AM Steven Ayre <steveayre at gmail.com> wrote:
>
>> Should point out that although it might be allowed in SDP's RFC that
>> doesn't necessarily mean it isn't restricted by other WebRTC
>> specifications. You'll probably want to look into those as well.
>>
>> On 4 August 2016 at 12:17, Colin Morelli <colin.morelli at gmail.com> wrote:
>>
>>> Steven,
>>>
>>> Thanks for the clarification - that's really helpful (it also means I
>>> can go file browser bugs which I'll do)
>>>
>>> Agreed it'll cause interop issues (for example the ones seen in WebRTC).
>>> It's too bad, because it could be helpful in a few different scenarios.
>>>
>>> That said, for now I'm just looking to slowly start using it on devices
>>> that will have problems with IP addresses. Does anyone know if there's a
>>> way, via a channel var, to set the advertised address in the SDP?
>>>
>>> Best,
>>> Colin
>>>
>>> On Thu, Aug 4, 2016 at 7:03 AM Steven Ayre <steveayre at gmail.com> wrote:
>>>
>>>> RFC4566 5. SDP Specification
>>>> "A session description can contain domain names in the "o=", "u=", "e=",
>>>> "c=", and "a=" lines."
>>>>
>>>> It's a detail I'd expect some implementations may have skipped over
>>>> though so I'd expect it could lead to interop issues. Also you need to
>>>> assume it will resolve to the IP you expect, not necessarily the case if it
>>>> resolves to multiple IPs for example or it has changed and the TTL has not
>>>> expired yet. And it might not play well with SIP ALGs. I'd avoid it. That's
>>>> not evidence based, purely gut instinct.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On 3 August 2016 at 06:10, 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?
>>>>>
>>>>>
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