[Freeswitch-users] domain vs. domain_name variables

Sat Aug 24 05:03:59 MSD 2013

It took me like an hour to compose this explanation.....I hope it at least
gives you an idea.

"domain" is a core variable its used as a fallback in certain situations
when its defined and no other value is specified for domain.
It's also used in the default configuration as a pre-processor substitution
with the $${domain} notation which is substituted into the sofia profiles
and conference etc.

"domain_name" is a variable that only exists in the scope of the demo
dialplan.  Its set initially as a global in vars.xml to whatever domain is
set to as a base value.
>From there its only set on a per-call basis to override and used in per
call dialplan logic.

Its is not true that domain must be an IP.  It defaults to the same value
as local_ip_v4 to make sure the system works on any box without any
configuration.
If you have a working FQHN that points to your box, you should set that
value in your domain var instead of the ip if you want things to reference
the actual domain name.

I think once you learn that way the config files are setup in the default
distribution are purely arbitrary the more sense it may begin to make.

The thing that made your head hurt is trying to explain that in SIP there
is a separation from the host portion of a URI and the IP its sending the
packet to.
Because of PROXIES etc you can easily send a SIP packet to a specific
address that contains a request URI or To: header with a different host
name or ip.

think of domain as referring to the host portion of a user at host concept.
 The same notion of a REALM in radius.  In SIP and in FS that can be an IP
or a FQHN and it need not exist in the TLD dns on the internet or it can
match one that exists and function on its own because it's not directly
tied to dns.  (For the sake of sanity do not use a real domain name that is
not yours even if it works).

Basically the path of least resistance is to keep all these names aligned..
This is what the default config does for you because you set the domain
variable once and its pre-processed into all the key places in the config
that have domains so they are the same everywhere.

Say you set it to example.com

* The default directory will have a domain defined called example.com with
the default 1000-1019 extensions.
* The internal sip profile will associate the internal profile with
example.com and force any registrations etc to find that domain for auth.
* The conferences will use example.com for presence etc.

Then it uses domain_name in the extensions etc as a clone of that
example.com domain that you can change at runtime on a per call basis.
 Most likely in the default config with no changes this value will remain
example.com the whole time and there is no difference.

Why?

Because people love multi-home stuff and they want to configure all of
these things separately and once they start doing this, the config still is
usable.

So:

FS never resolves domains to the IP and vice versa for you like it might in
your unix environment or in a web browser.  IP and FQHN have the same
significance in sip packets as a unique realm string.  It's only because
you are binding the SIP UA to ${local_ip_v4} that your sip works on the IP.

The way SIP was designed to work, you would define a SRV record for the
host name used in your sip uri and then that IP would be used in place of a
default A record lookup.  We can just as easily override that in a client
by forcing the fields for the proxy address and domains.

Say you used example.com like I mentioned above and your valid IP was
200.8.8.8

You could change domain=example.com and restart FS and it would still come
up.

Then you could go take a sip soft phone and play with the advanced settings
and set the proxy addr to 200.8.8.8 and set the host or domain field to
example.com and configure it to always send calls to the proxy addr.

Now you can use example.com in your phones all day long even though its not
really your domain because its just saying that in the packets and you
explicitly showed it what server to use.

Next, instead of example.com you could use 1.2.3.4 (or some real ip) as the
domain even though it's obviously silly.

If you turn on the siptrace you'll see the packets hit your box and using
those values like 1.2.3.4 and example.com in the host portion and talk to
your client over the actual IP of the server.

On Fri, Aug 23, 2013 at 4:55 PM, Karl Schmidt <karl at xtronics.com> wrote:

> On 08/23/2013 03:28 PM, Stanislav Sinyagin wrote:
> > What is the difference between ${domain} and ${domain_name} variables?
> Both are used in the source
> > code, and example configs set them to the same value.
> >
> > What is the design consideration behind?
> >
> > Why not merging them into one variable?
> >
>
> This is an issue that has me a bit puzzled as well.
>
> domain in vars.xml is supposed to be an IP address ( IMO Should have been
> called domain_ip )
> domain_name is supposed to be a FQDN I think. grepping the configs tells
> me domain_name is never
> used in the default config so you can probably ignore it.
>
> What is also not clear is the multiple uses of the term domain:
>
>
>  From the wiki -
>
> https://wiki.freeswitch.org/wiki/Sofia.conf.xml#The_Relationship_Between_SIP_Profiles_and_Domains:
>
>  > The domains inside the XML registry are completely different from the
> domains on the internet and
>  > again completely different from domains in sip packets. The profiles
> are again entirely different
>  > from any of the above. Its up to you to align them if you so choose.
>
> OK that made my head hurt.
>
> In some places in FS 'domain' = domain_IP_address
>
> Here it says that SIP profile domain != IP-domain != SIP packet domain.
>
> So I know what it isn't, but it might also help if I knew what it IS!
>
> So, I think the domain definition in sofia MIGHT be a grouping of
> profiles? Then as you read on, it
> tells us that a domain is a domain.
>
> " FreeSWITCH works off the concept of users and domains just like email."
>
> The books nor the wiki nor googling the mailing list makes this clear.
>
> Both the internal and external profiles set the name of the sofia-domain
> to all and $ sofia status
> gives the names as internal and external (after the directory? ).
>
>
>
>
>
> --------------------------------------------------------------------------------
> Karl Schmidt                                  EMail Karl at xtronics.com
> Transtronics, Inc.                              WEB
> http://secure.transtronics.com
> 3209 West 9th Street                             Ph (785) 841-3089
> Lawrence, KS 66049                              FAX (785) 841-0434
>
> Reality isn't fair, but that it is where I live. -kps
>
> --------------------------------------------------------------------------------
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> 
> 
>
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://wiki.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
>

-- 
Anthony Minessale II

FreeSWITCH http://www.freeswitch.org/
ClueCon http://www.cluecon.com/
Twitter: http://twitter.com/FreeSWITCH_wire

AIM: anthm
MSN:anthony_minessale at hotmail.com
GTALK/JABBER/PAYPAL:anthony.minessale at gmail.com
IRC: irc.freenode.net #freeswitch

FreeSWITCH Developer Conference
sip:888 at conference.freeswitch.org
googletalk:conf+888 at conference.freeswitch.org
pstn:+19193869900
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20130823/534343e6/attachment-0001.html 