[Freeswitch-users] DNS resolving for REGISTER requests

Mon Jun 24 13:01:22 UTC 2019

Hello Mike,

thanks for getting in the discussion!

I have a pcap-trace from last saturday containing sip and dns where i
can see the following behaviour:

11:39:32 FS does an SRV-Lookup for _sip._tcp.reg.sip-trunk.telekom.de
         -> Answer contains three records with TTL:3600
         FS does an A-Lookup for the record with the lowest priority
         -> Answer contains an IPv4 adress with TTL:216

FS registers to the provided ip address and re-registers every ~ 5 minutes

But there is no more dns traffic for the rest of the day (~ 12.5 hours)...

Version is 1.8.2-3-a98a958ac3~64bit on Debian Stretch.

Could this be an issue with the systems resolving logic (libnss) or is
the resolving completly done by FS itself?

Am 6/24/19 um 2:19 PM schrieb Mike Jerris:
> if the DNS entries haven’t yet expired then freeswitch won’t query again.
> The provider should set lower expiration on their records before a change
> or wait the full expiration after making a change to
> actually move hosts or they will cause this issue.  This has always been
> how the DNS system works.
> 
> On Mon, Jun 24, 2019 at 8:14 AM Sebastian Denz <denzs at gonicus.de> wrote:
> 
>> That is already the case..
>>
>> When FS starts up it does an SRV-Lookup which contains several adresses.
>>
>> One thing is.. the old endpoint is still working..
>>
>> The provider just changes the IP behind the A record of the first SRV
>> result.
>>
>> But the main problem is that FS does not use DNS at all before sending a
>> REGISTER... So i doubt this can be workarounded without touching the
>> code of FS or (and that is what i am going to do) use an external script
>> to detect the change and then trigger a gateway restart in FS...
>>
>> Am 6/24/19 um 1:30 PM schrieb Giovanni Maruzzelli:
>>> Maybe, just maybe, putting all addresses in srv records, FS will read
>> that
>>> at startup, then try them all if first fail? No idea if works... Just
>>> curious...
>>>
>>>
>>>
>>> On Mon, Jun 24, 2019, 12:18 Sebastian Denz <denzs at gonicus.de> wrote:
>>>
>>>> I already thought about something like that..
>>>>
>>>> But the main reason for the problem seems to be, that FreeSWITCH does
>>>> not query the dns (remote or local) at all before sending the
>>>> REGISTER... :-/
>>>>
>>>> I could workaround the current issue easily by using static addresses
>>>> but then i would loose the failover capability and i would have to check
>>>> for changes manually or by script... normally dns would just solve that
>>>> by itself :)
>>>>
>>>> I think i could put Kamailio in front of FreeSWITCH and let it handle
>>>> the dns resolution, but that feels like using a sledgehammer to crack a
>>>> nut ;)
>>>>
>>>> And i would prefer a tiny approach, ideally with FreeSWITCH behaving
>>>> correctly...?!
>>>>
>>>> Am 6/24/19 um 12:24 PM schrieb Giovanni Maruzzelli:
>>>>> obviously, you can locally provide dns with dnsmasq or such, easily
>>>>> configured, for other domains too.
>>>>>
>>>>> Maybe you can put all SRV addresses, with different weights, in your
>> own
>>>>> (eg, locally defined) zone definition for deutsche telekom, and
>>>> freeswitch
>>>>> will try them all.
>>>>>
>>>>> Not sure this will work, but maybe yes :)
>>>>>
>>>>>
>>>>>
>>>>> On Mon, Jun 24, 2019 at 12:19 PM Sebastian Denz <denzs at gonicus.de>
>>>> wrote:
>>>>>
>>>>>> Thank you for giving me that pointer!
>>>>>>
>>>>>> I thought i would have searched for everything regarding that topic,
>>>>>> but obviously i missed that post!
>>>>>>
>>>>>>
>>>>>>
>>>>
>> https://lists.freeswitch.org/pipermail/freeswitch-users/2018-January/128837.html
>>>>>>
>>>>>> I'll contact Kai directly as i was not able to found a corresponding
>>>>>> issue in the tracker...
>>>>>>
>>>>>> But if anyone has another idea regarding the problem, i would of
>> course
>>>>>> appreciate any hints too! ;)
>>>>>>
>>>>>> Sebastian
>>>>>>
>>>>>> Am 6/24/19 um 11:21 AM schrieb Giovanni Maruzzelli:
>>>>>>> I believe this question  was already asked in the past in this
>> mailing
>>>>>>> list, and IIRC the answer was no.
>>>>>>>
>>>>>>> You may wanto to check on the mailing list archives (in signature),
>>>>>> because
>>>>>>> maybe my merory is wrong.
>>>>>>>
>>>>>>> -giovanni
>>>>>>>
>>>>>>>
>>>>>>> On Mon, Jun 24, 2019 at 11:14 AM Sebastian Denz <denzs at gonicus.de>
>>>>>> wrote:
>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> i am using FreeSWITCH as SBC to our SIP provider (Deutsche Telekom
>> in
>>>>>>>> germany).
>>>>>>>>
>>>>>>>> This works quite well, but ~ once in a month we are unable to do
>>>>>>>> outbound calls.
>>>>>>>>
>>>>>>>> It turned out, that the provider changes some IPs from time to
>> time..
>>>>>>>>
>>>>>>>> That leads to FreeSWITCH being registered to the old IP while
>>>>>>>> INVITE-requests of new dialogs are sent to the new address. The
>>>> provider
>>>>>>>> terminates this with 403 - forbidden.
>>>>>>>>
>>>>>>>> The registration happens every 5 minutes, but FreeSWITCH does not
>>>> update
>>>>>>>> the dns cache for the target IP address. So i gets stuck in that
>>>>>>>> situation being registered on the old IP while sending INVITEs to
>> the
>>>>>>>> new one..
>>>>>>>>
>>>>>>>> The only solution to that is reloading the profile or restarting
>>>>>>>> FreeSWITCH...
>>>>>>>>
>>>>>>>> Is there an option to make FreeSWITCH asking the dns _before every_
>>>>>>>> REGISTER? Or do you have any other suggestion on how to fix this?
>>>>>>>>
>>>>>>>> Best regards,
>>>>>>>> Sebastian Denz
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>
>> _________________________________________________________________________
>>>>>>>>
>>>>>>>> The FreeSWITCH project is sponsored by SignalWire
>>>>>> https://signalwire.com
>>>>>>>> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN
>>>>>>>> services.
>>>>>>>> Build your next product on our scalable cloud platform.
>>>>>>>>
>>>>>>>> Join our online community to chat in real time
>>>>>>>> https://signalwire.community
>>>>>>>>
>>>>>>>> Professional FreeSWITCH Services
>>>>>>>> sales at freeswitch.com
>>>>>>>> https://freeswitch.com
>>>>>>>>
>>>>>>>> Official FreeSWITCH Sites
>>>>>>>> https://freeswitch.com/oss
>>>>>>>> https://freeswitch.org/confluence
>>>>>>>> https://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
>>>>>>>> https://freeswitch.com
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>
>> _________________________________________________________________________
>>>>>>>
>>>>>>> The FreeSWITCH project is sponsored by SignalWire
>>>> https://signalwire.com
>>>>>>> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN
>>>>>> services.
>>>>>>> Build your next product on our scalable cloud platform.
>>>>>>>
>>>>>>> Join our online community to chat in real time
>>>>>> https://signalwire.community
>>>>>>>
>>>>>>> Professional FreeSWITCH Services
>>>>>>> sales at freeswitch.com
>>>>>>> https://freeswitch.com
>>>>>>>
>>>>>>> Official FreeSWITCH Sites
>>>>>>> https://freeswitch.com/oss
>>>>>>> https://freeswitch.org/confluence
>>>>>>> https://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
>>>>>>> https://freeswitch.com
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>
>> _________________________________________________________________________
>>>>>>
>>>>>> The FreeSWITCH project is sponsored by SignalWire
>>>> https://signalwire.com
>>>>>> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN
>>>>>> services.
>>>>>> Build your next product on our scalable cloud platform.
>>>>>>
>>>>>> Join our online community to chat in real time
>>>>>> https://signalwire.community
>>>>>>
>>>>>> Professional FreeSWITCH Services
>>>>>> sales at freeswitch.com
>>>>>> https://freeswitch.com
>>>>>>
>>>>>> Official FreeSWITCH Sites
>>>>>> https://freeswitch.com/oss
>>>>>> https://freeswitch.org/confluence
>>>>>> https://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
>>>>>> https://freeswitch.com
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>> _________________________________________________________________________
>>>>>
>>>>> The FreeSWITCH project is sponsored by SignalWire
>> https://signalwire.com
>>>>> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN
>>>> services.
>>>>> Build your next product on our scalable cloud platform.
>>>>>
>>>>> Join our online community to chat in real time
>>>> https://signalwire.community
>>>>>
>>>>> Professional FreeSWITCH Services
>>>>> sales at freeswitch.com
>>>>> https://freeswitch.com
>>>>>
>>>>> Official FreeSWITCH Sites
>>>>> https://freeswitch.com/oss
>>>>> https://freeswitch.org/confluence
>>>>> https://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
>>>>> https://freeswitch.com
>>>>>
>>>>
>>>>
>>>>
>> _________________________________________________________________________
>>>>
>>>> The FreeSWITCH project is sponsored by SignalWire
>> https://signalwire.com
>>>> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN
>>>> services.
>>>> Build your next product on our scalable cloud platform.
>>>>
>>>> Join our online community to chat in real time
>>>> https://signalwire.community
>>>>
>>>> Professional FreeSWITCH Services
>>>> sales at freeswitch.com
>>>> https://freeswitch.com
>>>>
>>>> Official FreeSWITCH Sites
>>>> https://freeswitch.com/oss
>>>> https://freeswitch.org/confluence
>>>> https://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
>>>> https://freeswitch.com
>>>
>>>
>>> _________________________________________________________________________
>>>
>>> The FreeSWITCH project is sponsored by SignalWire https://signalwire.com
>>> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN
>> services.
>>> Build your next product on our scalable cloud platform.
>>>
>>> Join our online community to chat in real time
>> https://signalwire.community
>>>
>>> Professional FreeSWITCH Services
>>> sales at freeswitch.com
>>> https://freeswitch.com
>>>
>>> Official FreeSWITCH Sites
>>> https://freeswitch.com/oss
>>> https://freeswitch.org/confluence
>>> https://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
>>> https://freeswitch.com
>>>
>>
>>
>> _________________________________________________________________________
>>
>> The FreeSWITCH project is sponsored by SignalWire https://signalwire.com
>> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN
>> services.
>> Build your next product on our scalable cloud platform.
>>
>> Join our online community to chat in real time
>> https://signalwire.community
>>
>> Professional FreeSWITCH Services
>> sales at freeswitch.com
>> https://freeswitch.com
>>
>> Official FreeSWITCH Sites
>> https://freeswitch.com/oss
>> https://freeswitch.org/confluence
>> https://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
>> https://freeswitch.com
> 
> 
> _________________________________________________________________________
> 
> The FreeSWITCH project is sponsored by SignalWire https://signalwire.com
> Enhance your FreeSWITCH install with disruptive priced SMS and PSTN services.
> Build your next product on our scalable cloud platform.
> 
> Join our online community to chat in real time https://signalwire.community
> 
> Professional FreeSWITCH Services
> sales at freeswitch.com
> https://freeswitch.com
> 
> Official FreeSWITCH Sites
> https://freeswitch.com/oss
> https://freeswitch.org/confluence
> https://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
> https://freeswitch.com
> 