[SR-Users] Wrong ACK to Provider

Daniel-Constantin Mierla miconda at gmail.com
Mon Sep 1 12:05:35 CEST 2014


How did you grab the pcap? All the variants (including the zip via http 
download) are not recognized by ngrep or wireshark.

Anyhow, I looked with a text editor inside the and I could see that the 
ACK is changing the r-uri -- it comes to kamailio with the contact from 
200ok, but goes out with a different hostname. You have some rules in 
kamailio.cfg that do that -- you should let the r-uri unchanged for ack 
-- routing is done via record-routing.

Cheers,
Daniel

On 29/08/14 16:12, Daniel-Constantin Mierla wrote:
> The last .zip file is also showing only 3 packets (different ones) -- 
> can you check the trace has all the packet before you compress? Maybe 
> you can put it somewhere on a server for download and send me the 
> link, so I get it over http.
>
> Cheers,
> Daniel
>
> On 29/08/14 09:36, Daniel-Constantin Mierla wrote:
>> I don't mind to receive directly attachments that can contain 
>> sensitive data. But you have to write an email via mailing list 
>> saying you do/did so.
>>
>> With gmail I am checking mostly the emails that are filtered with 
>> various rules, otherwise, the rest land together with a lot of 
>> spam/advertising and check them very rarely, if ever.
>>
>> So, as a reminder to anyone that did it -- if a conversation from 
>> mailing list was turned into a direct email to me only, it very 
>> unlikely to get answered soon, given the load I have -- better resend 
>> to mailing list.
>>
>> I had no time to look yet at the trace.
>>
>> Cheers,
>> Daniel
>>
>> On 29/08/14 07:08, Yuriy Gorlichenko wrote:
>>> My pcap file. Daniel sorry for first time sended message to your 
>>> private mail. Was a mistake.
>>>
>>>
>>> 2014-08-28 17:27 GMT+04:00 Daniel-Constantin Mierla 
>>> <miconda at gmail.com <mailto:miconda at gmail.com>>:
>>>
>>>
>>>     On 28/08/14 15:11, Olle E. Johansson wrote:
>>>>
>>>>     On 28 Aug 2014, at 14:57, Daniel-Constantin Mierla
>>>>     <miconda at gmail.com <mailto:miconda at gmail.com>> wrote:
>>>>
>>>>>
>>>>>     On 28/08/14 14:45, Olle E. Johansson wrote:
>>>>>>
>>>>>>     On 28 Aug 2014, at 14:14, Yuriy Gorlichenko
>>>>>>     <ovoshlook at gmail.com <mailto:ovoshlook at gmail.com>> wrote:
>>>>>>
>>>>>>>     Hello. I try to provide call scheme:
>>>>>>>
>>>>>>>     internal client  -> asterisk -> Kamailio -> provider ->
>>>>>>>     external endpoint call
>>>>>>>
>>>>>>>     when I make call I see this:
>>>>>>>
>>>>>>>     asterisk     kamailio   provider
>>>>>>>     invite -->       invite -->
>>>>>>>     <--     407
>>>>>>>                            ACK   -->
>>>>>>>                            invite w/Auth -->
>>>>>>>                   <--    100  <--    100
>>>>>>>                   <--    180  <--    180
>>>>>>>                   <--    183  <--    183
>>>>>>>                    <--    200  <--      200
>>>>>>>        ACK  -->   ACK  -->
>>>>>>>
>>>>>>>     My problem with last ACK, that I send to provider. Provider
>>>>>>>     ignores it, and sends me some OK packets. As resultI can
>>>>>>>     notend session ( answer to BYE 481 - transaction does not
>>>>>>>     exists). I think it is wrong ACK but can not undrtand where
>>>>>>>     I do mistake.
>>>>>>     Well, by letting the proxy handle authentication the INVITE
>>>>>>     tranction i closed without Asterisk knowing about it. So the
>>>>>>     ACK sent from the proxy and from Asterisk is for the same
>>>>>>     transaction, which messes things up. Asterisk does not know
>>>>>>     anything about the second invite. Letting the proxy handle
>>>>>>     authentiction breaks the SIP protocol in bad ways and is
>>>>>>     generally not a good solution.
>>>>>>     You may want to send another response to asterisk when you
>>>>>>     get the 407 so Asterisk retries and use the retry as a
>>>>>>     trigger for the second INVITE and add auth to that.
>>>>>     While breaking the cseq incrementation for authentication
>>>>>     (mentioned in the readme of uac), the Asterisk seems to do ok
>>>>>     here, because the ACK is coming from asterisk, but it is not
>>>>>     accepted by the provider.
>>>>     You are missing the fact that the ACK sent by Asterisk is
>>>>     already sent by the proxy. The INVITE w/AUth have a different
>>>>     cseq than the ACK.
>>>     Kamailio is doing serial forking in this case, so the first ack
>>>     is for the first branch that gets 407. This should be as usual
>>>     for serial/parallel forking.
>>>
>>>     Then, Kamailio is not increasing the cseq here -- that's the
>>>     limitation with uac auth module, because the authenticator
>>>     should normally reject it. But if it is authentication against
>>>     another kamailio, should just work.
>>>
>>>
>>>>>
>>>>>     The provider (having a plivo platform, based on the responses)
>>>>>     is running kamailio 4.1.2 in front (looking at 100 trying).
>>>>>
>>>>>     Authentication from kamailio to another kamailio using uac
>>>>>     module should work fine, as kamailio doesn't act as end user
>>>>>     UAC and doesn't care much of cseq.
>>>>     Won't the second ACK on the same transaction just be ignored,
>>>>     while it waits for an ACK on the new transaction?
>>>     It is the same transaction in this case, just two branches from
>>>     kamailio downstream, which is serial forking case, as mentioned
>>>     above.
>>>
>>>
>>>     Cheers,
>>>     Daniel
>>>
>>>     -- 
>>>     Daniel-Constantin Mierla
>>>     http://twitter.com/#!/miconda  <http://twitter.com/#%21/miconda>  -http://www.linkedin.com/in/miconda
>>>     Next Kamailio Advanced Trainings 2014 -http://www.asipto.com
>>>     Sep 22-25, Berlin, Germany ::: Oct 15-17, San Francisco, USA
>>>
>>>
>>>     _______________________________________________
>>>     SIP Express Router (SER) and Kamailio (OpenSER) - sr-users
>>>     mailing list
>>>     sr-users at lists.sip-router.org <mailto:sr-users at lists.sip-router.org>
>>>     http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
>>>
>>>
>>
>> -- 
>> Daniel-Constantin Mierla
>> http://twitter.com/#!/miconda  -http://www.linkedin.com/in/miconda
>> Next Kamailio Advanced Trainings 2014 -http://www.asipto.com
>> Sep 22-25, Berlin, Germany ::: Oct 15-17, San Francisco, USA
>
> -- 
> Daniel-Constantin Mierla
> http://twitter.com/#!/miconda  -http://www.linkedin.com/in/miconda
> Next Kamailio Advanced Trainings 2014 -http://www.asipto.com
> Sep 22-25, Berlin, Germany ::: Oct 15-17, San Francisco, USA

-- 
Daniel-Constantin Mierla
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Next Kamailio Advanced Trainings 2014 - http://www.asipto.com
Sep 22-25, Berlin, Germany ::: Oct 15-17, San Francisco, USA

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