Hello,
On 11/4/12 10:52 PM, Moacir Ferreira wrote:
Daniel,
I am "reading" a lot... However, I can’t still get the “logic” to
overcome my problem using Kamailio routing logic. I was willing to
have a dual-homed Kamailo+RTPproxy on a single server, where one
interface goes to the Internet and another one goes to my private
network. However, the private network is using the RFC1918 address
space. Kamailio's NAT detection mechanism forces the RTPproxy between
two UAs if they are using RFC1918 address space even if the 2 UAs are
at the IP subnet that the Kamailio server is. So, if I have a
“private” network using RFC1918 addresses, made of several remote
sites, all the RTP traffic would have to go to the Kamailio/RTPproxy,
causing a large and undesirable traffic on the WAN links. By other
hand, should I don’t care about getting all my RTP LAN/WAN traffic
being sent to Kamailio because I am using RFC1918 address space, I
could not find an "workable example" of configuring a dual-homed
Kamailio+RTPProxy that properly sets the rtpproxy_manage flags to make
it work.
RTPProxy is engaged on demand, it does not do rtp relaying just because
it finds a RFC1918 address. It is up to you when you want to call
rtpproxy_manage() function. So if the call comes from and goes to a
rfc1918 address, then don't execute rtpproxy_manage().
Cheers,
Daniel
Looking at your IPv4/IPv6 example, we can see that it could be
possible to tag a SIP transaction and decide latter if it were to go
from external to internal, internal to internal or external to
external. The example is quite easy to understand because you can
separate IPv6 from IPv4 transactions. However, what about the private
address space?
Any help would be really appreciated. If you can't help, what forum
can I post my questions and get some answers?
Moacir
> Date: Mon, 15 Oct 2012 09:10:30 +0200
> From: mico...@gmail.com
> To: sr-users@lists.sip-router.org
> CC: moacirferre...@hotmail.com
> Subject: Re: [SR-Users] Another NAT question
>
> Hello,
>
> you can detect that the call is coming from public/external interface
> and goes to private/internal interface.
>
> There are couple of ways to do it, one is to set a branch flag when
they
> register, saying it is from external or internal. Then based on src ip
> ($si) or rcv io ($Ri) of the invite and the branch flag from location,
> you decide to enforce the rtpproxy or not.
>
> Alternative is to look at the forced socket or destination ip after
> lookup location and get the info from there about the message flow.
>
> Cheers,
> Daniel
>
> On 10/13/12 11:43 PM, Moacir Ferreira wrote:
> > Hi,
> >
> > I have a scenario where I got a firewall with 3 interfaces:
internal, DMZ and external. All the traffic from internal going to
external is NATed. However, the traffic between internal and DMZ is
NOT NATed. The external and DMZ are using public IP addresses. On the
DMZ I have a Kamailio server running with RTPProxy + NAT Helper.
> >
> > Everything works fine when public (from the internet) users (UAs)
are behind NAT as Kamailio will force the RTP to go via RTPProxy.
However, when the public user has a public IP, it will fail to
establish the RTP to a user who registered on Kamailio coming from the
internal firewall interface.
> >
> > The reason is that, as I don't do NAT between internal and DMZ
firewall interfaces, Kamailio will not RTPRroxy in between the UAs
because, from the way Kamailio detects NAT, they are not behind NAT.
So the public user UA tries to reach a private IP address. If the
"inside" user tries to call a public user (a user on the Internet with
a public IP), it works.
> >
> > Yes, I could do NAT in between the internal and DMZ firewall
interfaces. However, this would force all RTP traffic of my UAs at the
LAN go to Kamailio RTPProxy, an bad effect that I would like to avoid.
> >
> > So my question is: what would be the best approach to solve this
issue using Kamailio and RTPProxy in such scenario?
> >
> > Cheers!
> > Moacir
> > _______________________________________________
> > SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing
list
> > sr-users@lists.sip-router.org
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>
> --
> Daniel-Constantin Mierla - http://www.asipto.com
> http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
> Kamailio Advanced Training, Berlin, Nov 5-8, 2012 -
http://asipto.com/u/kat
> Kamailio Advanced Training, Miami, USA, Nov 12-14, 2012 -
http://asipto.com/u/katu
>
--
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Kamailio Advanced Training, Berlin, Nov 5-8, 2012 - http://asipto.com/u/kat
Kamailio Advanced Training, Miami, USA, Nov 12-14, 2012 -
http://asipto.com/u/katu
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