[Users] openser and rtpproxy on multihomed host

[Alexander 'Leo' Bergolth]

On 06/06/2007 09:43 PM, Ovidiu Sas wrote:
> It all depends on your routing table.  The OS will choose the src IP
> for you unless you force it.

Yes, I guess I should set the preferred source address via the "src"
option to ip route.
Right now, I don't specify the preferred source address and it did use
the first IP for sending RTP traffic for some month now.
But since yesterday (no reboot or routing table change involved) it used
the second IP for sending which is bad because the incoming traffic is
destined to the first address.

> If you receive RTP traffic on one interface and want to send it from
> the other one, then you need to run rtpproxy in bridge mode,
> otherwise, you can run two rtpproxy in parallel (use -l to specify the
> interface) and use openser 1.3 (the trunk version) to choose between
> the two rtpproxy servers.

I don't think this will be necessary, thanks.

> BTW, why do you want to run openSER/rtpproxy in this scenario?

It just happened by accident. ;)
The server has two IP addresses in the same subnet for administrative
reasons but the SRV records for SIP are only pointing to one address. So
I can easily set the preferred source address for outgoing traffic with
ip route change default via <gw> dev eth0 src <ip_a>
... to this address.

Thanks,
--leo

> On 6/6/07, Alexander 'Leo' Bergolth <leo at strike.wu-wien.ac.at> wrote:
>> On 06/06/2007 07:29 PM, Klaus Darilion wrote:
>> > Alexander Bergolth wrote:
>> >> I'm experiencing problems using openser and rtpproxy on a
>> multihomed box
>> >> (IP addresses are 137.208.89.45 and 137.208.89.65).
>> >>
>> >> The client (firewalled) contacts the server via the first IP address
>> >> (137.208.89.45) but rtpproxy sometimes uses it's second IP
>> >> (137.208.89.65) in the "c=" SDP-information. (See below.)
>> >> However it _sends_ RTP packets from the _first_ IP address. Those
>> >> packets will never pass through the firewall, of course, since the
>> >> clients outgoing RTP traffic is sent to another IP address than the
>> >> incoming traffic is hitting the firewall from.
>> >>
>> >> Is there a way to tell rtpproxy to use the same IP-address both for
>> the
>> >> c= SDP header and as source address?
>> >
>> > I guess you need the bridge mode of rtp proxy. Take a look at the
>> "flags":
>> > http://openser.org/docs/modules/devel/nathelper#AEN296
>>
>> Yes, I did already read it but I still didn't get the clue yet. :(
>>
>> In my configuration, there is no internal and external net, both IP
>> addresses are in the same subnet using public IP addresses.
>>
>> What I'd like to achieve:
>> The openser/rtpproxy server has some IP addresses and receives and sends
>> SIP traffic on all of those interfaces.
>> rtpproxy should simply use that local IP address for its RTP connection
>> to the client from which the SIP traffic from the client came in.
>>
>> I've tried to use force_rtp_proxy("", "$Ri") but that leads to the
>> SDP-line "c=$Ri". Maybe the nathelper-module doesn't support
>> pseudo-variables?
>>
>> Cheers,
>> --leo
>> --
>> e-mail   ::: Alexander.Bergolth (at) wu-wien.ac.at
>> fax      ::: +43-1-31336-906050
>> location ::: Computer Center | Vienna University of Economics | Austria
>>
>>
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-- 
e-mail   ::: Alexander.Bergolth (at) wu-wien.ac.at
fax      ::: +43-1-31336-906050
location ::: Computer Center | Vienna University of Economics | Austria