[Freeswitch-users] DNS resolving for REGISTER requests

Mon Jun 24 13:19:02 UTC 2019

Using "sofia loglevel sresolv 9" i dont see any sres_cache_get() calls
at all before FS sends a REGISTER.

But they are done before any other (new) transaction.

Regarding RFC 3263 Section 4. this seems to be kinda valid,
because the ongoing RE-REGISTERS requests are happening in-dialog so
they are not a _new_ transaction?!

But from a practical point of view i would expect there should be a
mechanism which ensures the used IP is are still valid?!

So i think at least the internal dns cache should be used...

What do you suggest?

Is there anything else i can do to narrow this down and/or should i open
an issue in Jira?

Am 6/24/19 um 3:02 PM schrieb Mike Jerris:
> if that’s the case it’s an issue with the resolver cache in sofia-sip
> 
> On Mon, Jun 24, 2019 at 9:01 AM Sebastian Denz <denzs at gonicus.de> wrote:
> 
>> 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
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>>>>>>>>>> https://cluecon.com
>>>>>>>>>>
>>>>>>>>>> FreeSWITCH-users mailing list
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>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>
>>>>
>> _________________________________________________________________________
>>>>>>>>>
>>>>>>>>> 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
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>>>>>>>>> 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
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>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>
>> _________________________________________________________________________
>>>>>>>
>>>>>>> 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
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>>>>>>> UNSUBSCRIBE:
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>>>>>>> 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
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>>>>>> 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
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>>>>> 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
>>>>
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>>>> 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
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>>> 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
> 