[OpenSIPS-Users] UDP to TCP issue with Re-INVITE

Mickael Hubert mickael at winlux.fr
Mon Dec 16 07:05:37 EST 2019

Hi all,
I advanced in my LAB
I have this configuration:
SIP client (tcp: -- my NAT router --> (tcp:
opensips (udp: --> rest of infra (udp:

When I received the reinvite from "rest of infra" on private interface
(, I could see this log:

Dec 16 12:55:27 am-frontal1a-test /usr/local/sbin/opensips[26160]:
ERROR:tm:msg_send: send() to for proto tcp/2 failed
Dec 16 12:55:27 am-frontal1a-test /usr/local/sbin/opensips[26160]:
ERROR:tm:t_forward_nonack: sending request failed
Dec 16 12:55:27 am-frontal1a-test /usr/local/sbin/opensips[26160]: retcode
= -6

I don't know why OpenSIPS tries to send the Re-invite to client private IP
instead client public port and IP (natted).

Do you have an idea please ?


Le jeu. 12 déc. 2019 à 11:09, Mickael Hubert <mickael at winlux.fr> a écrit :

> Hi all,
> I have an issue, opensips doesn't want forward Re-INVITE during UDP to TCP
> mapping session.
> Customer (NATTED) -- TCP --> (public interface listen tcp:8060) OpenSIPS
> (private interface listen udp:5060) --> rest of infrastructure (udp:5060)
> I can send a call from customer to OpenSIPS (initial INVITE, 200OK, etc
> ...).
> But when I received Re-INVITE from UAS (sip session timer), OpenSIPS
> doesn't forward it to customer.
> You can see the call flow here:
> https://photos.app.goo.gl/eUSb5MvBhUfueaoM7
> You can see SIP messages and opensips's logs in txt file in attachment
> OpenSIPS handles on it's public interface:
> - Topology hiding
> - Nat detection
> Thanks a lot for you help !
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