Re: nist-sip 1.2 and NAT traversal : issue with ListeningPoint sentby field

Brian,

There is no need to modify the Via sentby to contain the public IP 
address. The receiver will fill in the 'received' parameter on the Via, 
and automatically route back via the public router

 From is not needed either, as it is only a logical address

Only the Contact and SDP need to be modified

Regards,
Jeroen

Brian Wyld wrote:
> Hi,
> 
> I've been using the NIST SIP stack, and recently updated to the latest
> version (note in passing, great job guys).
> 
> However, my code to deal with calls that are outbound thru a NAT'd router no
> longer works.... If anyone can explain what I'm doing wrong it'd be a great
> help.
> 
> Basically, I want to make calls out (send the INVITE) to destinations that
> may be either on an 'internal' network, or 'public' ie outside of a NATing
> router.
> There is no problem for the INVITE sending (using UDP), as the destination
> IP is routable in both cases. My code detects when the destination is going
> via NAT, gets the public IP of the router from a config file, and:
> 	- adds a Via header accordingly
> 	- fixes up the From, Contact etc URIs (change the local IP to the external
> IP)
> 	- ensures the RTP SDP IP is the external IP
> This all worked fine until I updated to 1.2....
> 
> Now, when I send to the public network, I get:
> javax.sip.TransactionUnavailableException: sentBy does not match the sentby
> setting of the ListeningPoint 62.212.123.79:5060
>         at
> gov.nist.javax.sip.SipProviderImpl.getNewClientTransaction(SipProviderImpl.j
> ava:304)
> 	... etc
> My external IP (in the Via, From, Contact etc) is 62.212.123.79 and my local
> IP (to which the ListeningPoint is bound) would have been 192.168.0.167
> (local server).
> 
> So, when I create the ListeningPoint at initialisation of the server
> process, I tried setting the sendby using setSentBy() to  be the external
> IP...
> 
> Now, it works when I send to an external destination, but not when I send to
> an internal one!
> 
> Is there a way to stop the ListeningPoint checking its sentby field against
> my Via, From etc headers? Or is my basic method (fixing up the headers
> myself) wrong, and I should do it another way? Or do I have to use 2
> SipProvider instances, one for internal calls (sentby=192.168.0.167:5060)
> and one for externals (sentby=62.212.123.79:5060)? (this is not my preferred
> solution....)
> 
> All ideas gratefully received....
> 
> Brian
> 
> [ Brian Wyld : Eloquant SA    ]
> [ Directeur technique         ]
> [ brian.wyld at eloquant.com  ]
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