[SR-Users] Nat problems

[David Zambrano]

Hi
Ive been trying to configure kamailio as a loadbalancer between two
transcoders that afterwards send all calls to a softswitch but I
currently have two problems.

My first and most important one is a NAT problem or so I think. All
calls in UDP work perfectly but when dealing with calls in TCP only
outgoing calls work, no incoming calls work. After doing some traces
on the network I realized that the transcoder is trying to reach the
router in front of the softphone and skipping the Kamailio
loadbalancer. The call never reaches the softphone so the phonecall
never completes. In UDP exactly the same thing happens, the call skips
the Kamailio loadbalancer but the call completes perfectly fine.

The other detail has to do with the actual loadbalancing and failover.
I was using the weight distribution and it works great except its
sending the same CSeq to both transcoders and then the softswitch is
receiving it twice and an error pops up at the softphone Ive been
using saying theres a duplicate CSeq. I was using the forward()
command after the dispatcher arguments. I changed it to the t_relay()
and it works as in it doesnt send the same CSeq twice but instead a
unique one to each transcoder so the Softswitch stopped winning but
then the failover doesnt work. Whenever it one goes down its till
trying to reach it. Im using roundrobin in the dispatcher config
because I noticed it doesnt send stuff to both transcoders but only to
the transcoder its going to actually use. I started to read that for
failover I need the user_avp module which I didnt install but then I
wonder how come failover worked before?

Thanks for your help

Cheers

David