[SR-Users] Kamailio v4.0.2, iPhone, TCP connection and PJLIB

Roberto Fichera kernel at tekno-soft.it
Wed Aug 14 11:51:18 CEST 2013


On 08/14/2013 11:31 AM, Daniel-Constantin Mierla wrote:

Hi,

> Hello,
>
> On 8/14/13 11:26 AM, Roberto Fichera wrote:
>> On 08/14/2013 11:20 AM, Daniel-Constantin Mierla wrote:
>>
>> Hi,
>>
>>> Hello,
>>>
>>> On 8/14/13 11:16 AM, Roberto Fichera wrote:
>>>> On 08/14/2013 10:19 AM, Daniel-Constantin Mierla wrote:
>>>>
>>>> Hi,
>>>>
>>>>> Hello,
>>>>>
>>>>> as you can see in the REGISTER, the phone give a public IP where it can be contacted and kamailio tries to deliver to
>>>>> that address sip:528 at 94.94.X.X:1274;transport=TCP
>>>>>
>>>>> REGISTER comes from another port, but that is allowed in SIP.
>>>> Yep! That's the problem
>>>>
>>>>> You should disable stun in the client and let the server care of nat traversal.
>>>> As already said all client doesn't use any stun-
>>> then how they discover the public IP address if they are behind NAT? Or did I misunderstand that they are behind NAT?
>> Yes! They are behind NAT! Shouldn't kamailio detect such behaviour so it will change the contact header and the other
>> fields accordingly using the nat_fix_XXXX functions?
> detection of whether a device is behind nat is done based on comparing source IP of the packet with the IP addresses
> in the SIP message. It is no other way from application point of view.
>
> If you look at the trace, the REGISTER has only public IP addresses, no private address. Also, the Via header is
> perfectly matching the the source IP and port of the packet.

Mhhh!!! That's true!

> Therefore, if the device is behind a nat in a private network, how does it discover the public IP or the NAT router?
> Is the nat router running a SIP ALG? Can you get the SIP trace on the device itself?

Good question! It's a cisco 877 but the conf doesn't have any kind of SIP related configuration. Does it handle
transparently the SIP traffic?

Cisco IOS Software, C870 Software (C870-ADVIPSERVICESK9-M), Version 12.4(15)T5, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2008 by Cisco Systems, Inc.
Compiled Thu 01-May-08 02:31 by prod_rel_team


> Cheers,
> Daniel
>




More information about the sr-users mailing list