Re: NAT and NOTIFY messages

Lauri,

Want to do a lttle wiki wirteup (please apply for content-developer or 
developer access to the project on java.net and send me your login id so 
I know who you are and can approve)? Else you can send me a code 
snipptet or how to and I can post it to the wiki. The question of  NAT 
traversal comes up an awful lot. Your findings could help others.

Thanks,

Regards

Ranga

Lauri Tielinen wrote:

> Thanks for the help. I got NAT working already last week after I 
> noticed  to use VIA header for the received IP & port, just as you 
> suggested.
>
> I guess whole confusion was because I was somehow in understanding 
> that this would have been something that JAIN-SIP would have done out 
> of the box. The fact that OK responses went nicely through the NAT 
> didn't help me on resolving the issue.
>
> Nevertheless, Jeroen's comments are valuable for anyone trying to get 
> SIP working through NAT.
>
> Best Regards,
>
> - Lauri
>
> [email protected] wrote:
>
>> Lauri,
>>
>> NAT traversal is quite tricky to get right, it may or may not work 
>> depending on the type of NAT device you have.
>> The best solution would probably be to use outbound (recent IETF 
>> draft) but that is not supported by JAIN 1.2.
>> If you add "rport" to the via header that the client adds, you may 
>> see (in the trace) on which port the NAT device sends it. Then you 
>> may need a hack which uses this port for the remote Contact header 
>> too (which is used as request URI to send the NOTIFYs to)
>>
>> The 1.2 API has support for rport, but the reverse direction will not 
>> work without modifications (not even using TCP)
>>
>> Regards,
>>
>> Jeroen
>>
>>> Lauri,
>>>
>>> Are you using the same provider to send out the NOTIFY as the 
>>> provider you use to respond to the SUBSCRIBE? . Maybe its a 
>>> different UDP socket which would be the case if you used a different 
>>> provider. That could be one reason.
>>>
>>> Regards
>>>
>>> Ranga
>>>
>>> Lauri Tielinen wrote:
>>>
>>>> Hello!
>>>>
>>>> I'm working on presence server using JAIN-SIP and I'm wondering if 
>>>> someone could give me some help with traversing through NAT.
>>>>
>>>> I've got following quite basic SIPp flow:
>>>> Client                Server
>>>> REGISTER  ---------->
>>>> 200       <----------
>>>> SUBSCRIBE ---------->
>>>> 200       <----------
>>>> NOTIFY    <----------
>>>> 200       ---------->
>>>>
>>>> Currently responses (200) are going nicely through the NAT with UDP 
>>>> and TCP, but I'm unable to get NOTIFY messages through to the client.
>>>>
>>>> Responses are sent by using server transaction and I've tested 
>>>> NOTIFY messages by using Dialog so far. I've also tried sending 
>>>> NOTIFY statelessly, but that fails naturally. I also tried setting 
>>>> CACHE_SERVER_CONNECTIONS and CACHE_CLIENT_CONNECTIONS to true, but 
>>>> didn't notice any difference.
>>>>
>>>> What approach would be correct to handle sending of NOTIFY 
>>>> messages? The NAT mapping is planned to be kept alive by sending 
>>>> REGISTER messages often enough. I'm feeling that I'm looking in 
>>>> wrong direction at the moment or missing something pretty simple so 
>>>> little help would be appreciated.
>>>>
>>>> I'm using latest JAIN-SIP 1.2 from CVS.
>>>>
>>>> Best Regards,
>>>>
>>>> - Lauri Tielinen
>>>>
>


-- 
M. Ranganathan 

Advanced Networking Technologies Division,
National Institute of Standards and Technology (NIST),
100 Bureau Drive, Stop 8920, Gaithersburg, MD 20899. 
tel:301 975 3664 , fax:301 590 0932 http://w3.antd.nist.gov/
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