16 Mar
2011
16 Mar
'11
8:17 p.m.
Am 16.03.2011 15:06, schrieb David:
Hello,
I have a Kamailio 3.0 server with two interfaces. 192.168.x.x and a
public interface.
I send PUBLISH out on the private interface to my presence server.
Everything else happens on the public address.
I did not use the "listen=" option in the config, so Kamailio was
automatically detecting my interfaces to bind to.
I always specify explicitly the sockets, thus I do not know hwo the
"auto" feature works.
Last night I had a provider sending packets in on TCP
and Kamailio was
sending out on UDP. Unfortunately, it kept using the private interface
despite that the IP was unreachable on this interface.
It looks like Kamailio uses the first interface it finds when converting
between TCP and UDP, and I believe that on the server, the private
interface was being listed first.
I finally added listen= in kamailio with all 4 interfaces ( tcp/udp
public and tcp/udp private ). I listed the public UDP interface first,
restarted and the packets started going out on the public interface.
Is this a feature or a bug ?
Probably it is just by design. If you do not tell Kamailio which
interface to use (force_send_socket) it somehow has to guess. If usually
tries to use the same socket on which the message was received. Probably
in case of protocol change that does not work.
How does Kamailio decide which interface to use ? What if I sent a
packet to an IP that is only reachable on one interface?
Either force the interface, or use mhomed=true (multihomed).
Actually, I always thought that the interface on which the request will
be sent is chosen by the OS (based on routing table) - Kamailio just
decides which src-IP address to use in the SIP message. If you set
mhomed=yes, then it opens a new socket to find out which IP will be
choosen be the OS, close the socket, use the IP in the message header,
and send it on the respective socket.
At the very least, I think that a note about this
difficulty should be
included in the default config so that future users don't have the same
issue I did.
Patches are welcome.
regards
Klaus