[SR-Users] BYE and TCP

[Kjeld Flarup]

Hello

I got an answer from the VOIP provider.

They claim that we have an error in our port forwarding. Because we 
advertise 5071, but traffic comes from another port.

As I understand, it is however impossible for TCP to send all traffic 
from just one port.

How is TCP SIP actually supposed to handle a BYE, when the client is 
behind NAT.

-------------------- Med Liberalistiske Hilsner ----------------------
    Civilingeniør, Kjeld Flarup - Mit sind er mere åbent end min tegnebog
    Sofienlundvej 6B, 7560 Hjerm, Tlf: 40 29 41 49
    Den ikke akademiske hjemmeside for liberalismen - www.liberalismen.dk

On 11/4/20 10:00 PM, Kjeld Flarup wrote:
>
> Hello again
>
> I have attached a Capture.
>
> My public IP is 194.255.22.44, and I have a port forward of 5071 in my 
> router
>
> The Raspberry Pi running the Kamailio is on 192.168.2.9 with an alias 
> 192.168.2.40
>
> My listening is setup like this
>
> listen=127.0.0.1:5071
> listen=eth0:5071  advertise 194.255.22.44:5071
> alias=194.255.22.44:5071
>
> Kamailio is forwarding an invite from a door phone thus I also rewrite 
> FROM:
>
> uac_replace_from("sip:"+$dbr(ra=>[0,1])+"@194.255.22.44:5071");
> And the failure route to
> $fu = "sip:"+$dbr(ra=>[0,0])+"@194.255.22.44:5071";
>
> In the route doing the INVITE I also set this:
>
> set_advertised_address("194.255.22.44:5071");
>
>
> Regarding tcp_reuse_port, if I set this I get this error, which I 
> understand is due to the way TCP works.
>
> Nov  4 18:38:41 scantronpbx /usr/sbin/kamailio[15864]: {1 ACK 16191 
> ACK C2Az-Xm2b0CEPyV5eQuz7yEf9IJo4PyJ} WARNING: <core> 
> [core/tcp_main.c:1061]: tcp_do_connect(): binding to source address 
> 192.168.2.40:5071 failed: Address already in use [98]
>
> I do have tcp_reuse_port=yes with this capture. But much to my 
> surprise, the 200 OK from is send to 37148, but the ACK to it comes 
> from 37150
>
>
> -------------------- Med Liberalistiske Hilsner ----------------------
>     Civilingeniør, Kjeld Flarup - Mit sind er mere åbent end min tegnebog
>     Sofienlundvej 6B, 7560 Hjerm, Tlf: 40 29 41 49
>     Den ikke akademiske hjemmeside for liberalismen -www.liberalismen.dk
> On 11/4/20 1:59 PM, Carsten Bock wrote:
>> Hi,
>>
>> I think you are searching for this parameter:
>>
>> http://www.kamailio.org/wiki/cookbooks/devel/core#tcp_reuse_port
>>
>> It basically tells the kernel not to choose a new port at random for 
>> a new connection, but it will try to reuse the existing port (in your 
>> case 5071).
>>
>> Thanks,
>> Carsten
>>
>>
>> --
>> Carsten Bock I CTO & Founder
>>
>> ng-voice GmbH
>>
>> Trostbrücke 1 I 20457 Hamburg I Germany
>> T +49 40 524 75 93-40 | M +49 179 2021244 I www.ng-voice.com 
>> <http://www.ng-voice.com/>
>>
>> Registry Office at Local Court Hamburg, HRB 120189
>> Managing Directors: Dr. David Bachmann, Carsten Bock
>>
>>
>>
>> Am Mi., 4. Nov. 2020 um 12:07 Uhr schrieb Kjeld Flarup 
>> <kjeld.flarup at liberalismen.dk <mailto:kjeld.flarup at liberalismen.dk>>:
>>
>>     Hello
>>
>>     I have a Kamailio running behind NAT, which sends calls to a VOIP
>>     service provider.
>>
>>     I have setup the Kamalio to listen on port 5071, and also setup a
>>     port
>>     forward in the router.
>>
>>     Now the problem is that with TCP, 5071 is not used for the
>>     dialog, but a
>>     new port is chosen everytime. This means that when the mobile phone
>>     called hands up, I never sees the BYE, because BYE is a new dialog.
>>
>>
>>     To which port is the server supposed to send the BYE, and what field
>>     tells the server this.
>>
>>
>>     -- 
>>     -------------------- Med Liberalistiske Hilsner
>>     ----------------------
>>         Civilingeniør, Kjeld Flarup - Mit sind er mere åbent end min
>>     tegnebog
>>         Sofienlundvej 6B, 7560 Hjerm, Tlf: 40 29 41 49
>>         Den ikke akademiske hjemmeside for liberalismen -
>>     www.liberalismen.dk <http://www.liberalismen.dk>
>>
>>
>>     _______________________________________________
>>     Kamailio (SER) - Users Mailing List
>>     sr-users at lists.kamailio.org <mailto:sr-users at lists.kamailio.org>
>>     https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>
>>
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users at lists.kamailio.org
>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.kamailio.org/pipermail/sr-users/attachments/20201105/d0eb79e5/attachment.htm>