Hello Daniel,

Thank you! Setting the mhomed parameter fixed it!

Regards,

Grant

From: sr-users [mailto:sr-users-bounces@lists.sip-router.org] On Behalf Of Daniel-Constantin Mierla
Sent: Wednesday, May 6, 2015 3:43 PM
To: Kamailio (SER) - Users Mailing List
Subject: Re: [SR-Users] Strange behavior for TCP and UDP SIP Routing

Hello,

do you have forwarding rules on your IP routing tables between the two interfaces? Have you enabled the mhomed global parameter?

For UDP, the default rule is to use incoming socket for sending the packets, unless mhomed is enabled.

For TCP is the kernel that has the final decision on the connection.

Note that you can also force a specific inteface with force_send_socket() or $fs= "...".

Cheers,
Daniel

On 06/05/15 15:26, Grant Bagdasarian wrote:

Hello,

I have a Kamailio machine configured with two interfaces. One public, one private.

Public Address: 10.10.10.10

Private Address: 192.168.1.10

Kamailio forwards the SIP packet to another local endpoint: 192.168.1.20

When a client sends a SIP packet using TCP to the public address of Kamailio, Kamailio relays the packet using its private interface (private address) to the other endpoint.

TCP: Client -> 10.10.10.10 -> 192.168.1.10 -> 192.18.1.20

When a client sends a SIP packet using UDP to the public address of Kamailio, Kamailio (or the OS) relays the packet using its public interface (public address) to the other endpoint.

UDP: Client -> 10.10.10.10 -> 10.10.10.10  -> 192.18.1.20

In the case of TCP, the source address is 192.168.1.10.

In the case of UDP, the source address is 10.10.10.10.

Everything is the same in the routing script for both UDP and TCP, except in route[relay] (see below)

Is this normal? What is causing this, the OS or Kamailio?

Route[RELAY] {

                …

                if($pr =~ "TCP") {

                               if (!t_relay_to_tcp()) {

                                               sl_reply_error();

                               }

                } else {

                               if (!t_relay_to_udp()) {

                                               sl_reply_error();

                               }

                }

}

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Daniel-Constantin Mierla
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