[Serusers] Where does SER get the public IP of a NATed uac from for sending as STATUS message?

Voipers Portugal voipers at gmail.com
Mon Dec 12 23:34:18 CET 2005


I'm not sure if what I am saying is correct but I think the 200 OK message
from the INVITE message tells the IP phone where to send the BYE and ACK
messages. So, if the 200 OK message was correctly corrected by
fix_nated_contact() it should work fine. But i think that Jan or another
expert user could confirm this.

Jose Simoes


On 12/12/05, Frank Fischer <frank.fischer at digitalnomads.ch> wrote:
>
> Hi Jan
> Hi all
>
> > > I have a problem with NATed UACs in my setup. Therefor i
> > would like to know
> > > where SER takes the public IP of a NATed UAC from, a
> > request is forwarded to
> > > (using the reply handler) if i call fix_nated_contact() to
> > rewrite the NATed
> > > UACs contact header. Is it always taken form the received
> > field in the
> > > location record?
> >
> >   From the source IP of the packet.
>
> Maybe my question was not asked clear enough. Just for clarification: SER
> receives a BYE from the called UAC and has to relay it to the calling UAC.
> Both UACs are natted. Now, where does SER get the public ip address from
> for
> the calling UAC that the BYE has to be relayed too? It sure can't be the
> source address of the received BYE request since this would be called UAC
> that sent the BYE. So I guess it would have to be read out from some field
> in the BYE request?
>
> I'm asking this, because i have a reproducable situation with different
> UACs
> (swissvoice ip10s and patton-inalp smartnodes) where SER relays the BYE to
> the PRIVATE ip address of the calling UAC instead to it's public ip
> address.
> With snom100 the BYE is relayed to the correct public ip addresse but to
> the
> port of the private address (meaning to port 5060). In the same BYE
> request
> i also find that the Request-Line contains the public IP address for the
> natted UAC (where i expected to find the private ip address) and the
> contact
> hf was not rewritten and contains the public ip address of the UAC). This
> is
> the second indication that there is something wrong with NAT handling.
>
> The nat-related (and most other too) parts of the script are taken from
> the
> onsip getting started document. There is no firewall or SIP ALG anywhere
> between SER and the natted UACs. I use mediaproxy in combination with
> nathelper. The call is successfully established and the voice channels
> work
> both way. The only effect you get on the phone from this behaviour is,
> that
> if the callee ends the phone, the caller doesn't get informed about that
> (since the BYE never arrives).
>
> Anyone has any idea what's going on in my setup? Anyone ever experience a
> similar situation?
>
> I'm very thankfull for any advice, hint, whatever....
>
> - Frank
>
>
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