[asterisk-dev] [Code Review] 3343: res_pjsip: Enable DNS support.

[Joshua Colp]

Olle E. Johansson wrote:
>
> On 12 Mar 2014, at 19:53, Joshua Colp <reviewboard at asterisk.org
> <mailto:reviewboard at asterisk.org>> wrote:
>
>> This change adds a configuration option for setting nameservers to
>> be used by the PJSIP DNS client. If this option is not set then the
>> system nameservers are retrieved and used instead.
>>
>> This also allows the nameservers to be changed by doing a reload.
>
> Why is this a good thing?

PJLIB-Util (part of pjproject) provides a DNS client which can 
optionally (but is highly suggested) to be used with PJSIP. It provides 
asynchronous DNS, SRV lookups, multiple record support, etc. Right now 
this isn't enabled so we are simply doing A/AAAA record lookups. The 
reason it's not enabled is that explicit nameservers *must* be provided 
to it when enabling it. It will not use the system ones by itself. The 
change up on reviewboard enables it by default using the system 
nameservers it finds, but with the ability to override or completely 
disable it if a user wants. The reason I also provide reload 
functionality is that people in #asterisk-dev expressed a concern that 
users may change nameservers but don't want to restart Asterisk, which 
is understandable.

Cheers,

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org