[Blink] Blink Ubuntu DNS lookup deadlock?
g4-lisz at tonarchiv.ch
g4-lisz at tonarchiv.ch
Thu Dec 1 03:56:45 CET 2022
I guess you mean voipgateway.org as root domain, not the '.' domain
above TLDs...
I don't see an issue here. The idea of CNAME is to point to other names.
They don't have to be in the same zone file.
guest1.voipgateway.org points to ws1.voipgateway.org so this is even the
same domain.
Cheers
Till
On 30.11.22 23:50, GA Georgescu wrote:
> CNAME on the root domain is not allowed in DNS. Each resolver may yield a different result when coping to this anomaly.
>
> As a start, just remove it and we can look at what happens afterwards.
>
> Adrian
>
>> On 30 Nov 2022, at 14:17, g4-lisz at tonarchiv.ch wrote:
>>
>> It's really strange, right now it's working but I don't know what has changed.
>>
>> Again I did some network sniffing on port 53 and it seems a bit random how Blink is reacting to the DNS replies: Sometimes it simply ignores the CNAME answer to the NAPTR and doesn't send a request for ws1.voipgateway.org. Sometimes it sends a NAPTR request for ws1.voipgateway.org...
>>
>> IMHO the same randomness decides if everything works or fails: If it interprets the NAPTR replies as "contains no answer", then the SRV requests are also sent and interpreted correctly.
>> If the first request is mistakenly handled like a timeout, all the other requests are not sent and the whole process seems to block somewhere.
>>
>> Some timing issue in the DNS resolve threads?
>>
>> Cheers
>> Till
>>
>> On 30.11.22 15:42, g4-lisz at tonarchiv.ch wrote:
>>> Hi
>>>
>>> thank you for your replies.
>>>
>>> I'm a bit more familiar with DNS than with VOIP... If I get it right the NAPTR is optional and SIP should work without it.
>>>
>>> CNAME can always be a reply to a DNS lookup, it just means: The name you are looking for is an alias, i.e. guest1.voipgateway.org is a virtual domain. IMHO Blink does the right thing and sends a second request for ws1.voipgateway.org.
>>>
>>> But for ws1.voipgateway.org there's a NAPTR either. The SOA reply only means that this an authoritative answer.
>>>
>>> IMHO the problem comes with the second DNS reply which contains only a SOA. Blink seams not to handle this and runs into a timeout.
>>>
>>> Strangely enough the whole issue doesn't always appear and all works fine sometimes. Then I get the same log lines like Timen de Mes:
>>>
>>> 2022-11-30 15:35:49.340913 [blink 2]: DNS lookup NAPTR guest1.voipgateway.org failed: DNS response contains no answer
>>> 2022-11-30 15:35:49.405083 [blink 2]: DNS lookup SRV _sip._udp.guest1.voipgateway.org failed: DNS record does not exist
>>> 2022-11-30 15:35:49.463001 [blink 2]: DNS lookup SRV _sip._tcp.guest1.voipgateway.org failed: DNS record does not exist
>>> 2022-11-30 15:35:59.932458 [blink 2]: DNS lookup SRV _sips._tcp.guest1.voipgateway.org failed: DNS record does not exist
>>> 2022-11-30 15:35:59.960770 [blink 2]: DNS lookup A guest1.voipgateway.org succeeded, ttl=3600: 212.117.203.57
>>>
>>> Best regards
>>> Till
>>>
>>> On 30.11.22 12:10, Adrian Georgescu wrote:
>>>> $dig cname guest1.voipgateway.org
>>>>
>>>> ;; QUESTION SECTION:
>>>> ;guest1.voipgateway.org. IN CNAME
>>>>
>>>> ;; ANSWER SECTION:
>>>> guest1.voipgateway.org. 21600 IN CNAME ws1.voipgateway.org.
>>>>
>>>> The CNAME should not be there for the domain name.
>>>>
>>>> —
>>>> Adrian
>>>>
>>>>
>>>>
>>>>
>>>>> On 30 Nov 2022, at 07:15, Tijmen de Mes <tijmen at ag-projects.com> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> I looked at it a bit more and the fact that a CNAME is returned could happen.
>>>>>
>>>>> However in my Blink I can’t reproduce this fault, I used the domain guest1.voipgateway.org and I could register(?), if I made a call I got a prompt.
>>>>>
>>>>> This is how my logs look:
>>>>>
>>>>> 1 2022-11-30 10:59:46.901093 [blink 4977]: DNS lookup NAPTR guest1.voipgateway.org failed: DNS response contains no answer
>>>>> 2 2022-11-30 10:59:46.901540 [blink 4977]: DNS lookup SRV _sips._tcp.guest1.voipgateway.org failed: DNS record does not exist
>>>>> 3 2022-11-30 10:59:46.901950 [blink 4977]: DNS lookup SRV _sip._tcp.guest1.voipgateway.org failed: DNS record does not exist
>>>>> 4 2022-11-30 10:59:46.902359 [blink 4977]: DNS lookup SRV _sip._udp.guest1.voipgateway.org failed: DNS record does not exist
>>>>> 5 2022-11-30 10:59:46.902618 [blink 4977]: DNS lookup A guest1.voipgateway.org succeeded, ttl=2675: 212.117.203.57
>>>>>
>>>>> I don’t have the flatpack so I can’t tell you if something is wrong in there. The lookups are handled by python3-sipsimple.
>>>>>
>>>>> Best regards,
>>>>>
>>>>> Timen de Mes
>>>>> —
>>>>> AG Projects
>>>>>
>>>>>> Op 30 nov. 2022, om 10:35 heeft Tijmen de Mes <tijmen at ag-projects.com> het volgende geschreven:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> The fact that you see the timeouts could be a bug.
>>>>>>
>>>>>> The problem is that a NAPTR does exist and is a CNAME? I’ve never seen this and I am not sure this is even valid in DNS.
>>>>>>
>>>>>> AFAIK a NAPTR in this case should return something like:
>>>>>>
>>>>>> 20 100 "s" "SIP+D2U" "" _sip._udp.sip2sip.info.
>>>>>> 10 100 "s" "SIP+D2T" "" _sip._tcp.sip2sip.info.
>>>>>> 25 100 "s" "SIPS+D2T" "" _sips._tcp.sip2sip.info.
>>>>>>
>>>>>> After this a SRV lookup would be done.
>>>>>>
>>>>>> Are you able to register your account?
>>>>>>
>>>>>>
>>>>>> Best regards,
>>>>>>
>>>>>> Tijmen de Mes
>>>>>> —
>>>>>> AG Projects
>>>>>>
>>>>>>> Op 29 nov. 2022, om 17:44 heeft g4-lisz at tonarchiv.ch het volgende geschreven:
>>>>>>>
>>>>>>> Hi there
>>>>>>>
>>>>>>> A few days ago I updated my OS to Pop! OS / Ubuntu 22.04 LTS with the Blink flatpack V5.5.0
>>>>>>>
>>>>>>> A few times it worked flawlessly, but most of the time, starting a call lags a lot and it simply fails with a beep after a few minutes without any further message.
>>>>>>>
>>>>>>> The logs shows issues with DNS:
>>>>>>>
>>>>>>> 2022-11-29 15:22:37.533993 [blink 2]: DNS lookup NAPTR guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:22:37.534465 [blink 2]: DNS lookup SRV _sip._udp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:22:37.534699 [blink 2]: DNS lookup SRV _sip._tcp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:22:37.534909 [blink 2]: DNS lookup SRV _sips._tcp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:22:37.535100 [blink 2]: DNS lookup A guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:22:37.637499 [blink 2]: DNS lookup TXT xcap.guest1.voipgateway.org failed: DNS record does not exist
>>>>>>> 2022-11-29 15:23:08.049049 [blink 2]: DNS lookup NAPTR guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:08.049976 [blink 2]: DNS lookup SRV _sips._tcp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:08.050817 [blink 2]: DNS lookup SRV _sip._tcp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:08.051510 [blink 2]: DNS lookup SRV _sip._udp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:08.052161 [blink 2]: DNS lookup A guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:38.498519 [blink 2]: DNS lookup NAPTR guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:38.498998 [blink 2]: DNS lookup SRV _sip._udp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:38.499612 [blink 2]: DNS lookup SRV _sip._tcp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:38.500547 [blink 2]: DNS lookup SRV _sips._tcp.guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:23:38.501826 [blink 2]: DNS lookup A guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>> 2022-11-29 15:24:08.946267 [blink 2]: DNS lookup NAPTR guest1.voipgateway.org failed: no DNS response received, the query has timed out
>>>>>>>
>>>>>>> and so on.
>>>>>>>
>>>>>>> But in reality there are no DNS timeouts. IMHO the issue is that Blink doesn't handle the DNS answers right and then somehow deadlocks on the first NATPR request.
>>>>>>>
>>>>>>> I did some sniffing on port 53 and there are no DNS requests for SRV:
>>>>>>>
>>>>>>> 192.168.178.23 192.168.178.1 DNS 82 Standard query 0x1eab NAPTR guest1.voipgateway.org
>>>>>>> 192.168.178.1 192.168.178.23 DNS 162 Standard query response 0x1eab NAPTR guest1.voipgateway.org CNAME ws1.voipgateway.org SOA ns1.backbone.ch
>>>>>>> 192.168.178.23 192.168.178.1 DNS 79 Standard query 0x3a0b NAPTR ws1.voipgateway.org
>>>>>>> 192.168.178.1 192.168.178.23 DNS 141 Standard query response 0x3a0b NAPTR ws1.voipgateway.org SOA ns1.backbone.ch
>>>>>>> [ ..nothing concerning VOIP...]
>>>>>>> 192.168.178.23 192.168.178.1 DNS 82 Standard query 0xb5c0 NAPTR guest1.voipgateway.org
>>>>>>> 192.168.178.1 192.168.178.23 DNS 162 Standard query response 0xb5c0 NAPTR guest1.voipgateway.org CNAME ws1.voipgateway.org SOA ns1.backbone.ch
>>>>>>> 192.168.178.23 192.168.178.1 DNS 79 Standard query 0x5cba NAPTR ws1.voipgateway.org
>>>>>>> 192.168.178.1 192.168.178.23 DNS 141 Standard query response 0x5cba NAPTR ws1.voipgateway.org SOA ns1.backbone.ch
>>>>>>> [ ..nothing concerning VOIP...]
>>>>>>> 192.168.178.23 192.168.178.1 DNS 82 Standard query 0x63b5 NAPTR guest1.voipgateway.org
>>>>>>> 192.168.178.1 192.168.178.23 DNS 162 Standard query response 0x63b5 NAPTR guest1.voipgateway.org CNAME ws1.voipgateway.org SOA ns1.backbone.ch
>>>>>>> 192.168.178.23 192.168.178.1 DNS 79 Standard query 0x6dce NAPTR ws1.voipgateway.org
>>>>>>>
>>>>>>> The queries timeout occurs because Blink does not issue the requests. IMHO Blink does not handle the SOA replies and somehow deadlocks, so other requests are never sent.
>>>>>>>
>>>>>>> Instead it should simply return: NAPTR record does not exist. Go on...
>>>>>>>
>>>>>>> Cheers
>>>>>>> Till
>>>>>>>
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