[OpenSIPS-Users] tls -> udp

Bogdan-Andrei Iancu bogdan at opensips.org
Thu Mar 7 04:46:39 EST 2019

Hi John,

For (2), there is nothing special you need to do - the double_rr is by 
default enabled and you just need to do record_route() - opensips is 
automatically figure out that there is a protocol changing and do a 
double RR headers.

Regarding (1) and (3) - the proto info in RURI/destination is overriding 
the info in forced socket - if you have a explicit UDP destination, but 
a TLS socket forced, the socket will be discarded and a proper one (UDP) 
will be found.

Shortly said, you need only (1).


Bogdan-Andrei Iancu

OpenSIPS Founder and Developer
OpenSIPS Summit 2019

On 02/13/2019 11:15 AM, John Quick wrote:
> Hi Johan,
> I've configured Proxy servers to do this a few times.
> You should do the following:
> 1) For Requests going from TLS to UDP, change any occurrence of
> "transport=tls" in the R-URI parameters. I use the following to do this:
> subst_uri('/transport=tls/transport=udp/I');
> 2) Make sure OpenSIPS adds correct Record-Route headers.
> Default behaviour in this case is to add 2 RR headers when you call
> record_route(). Make sure double_rr has not been disabled in the modparam
> section.
> One header describes the TLS socket and the other header describes the UDP
> socket. These are needed for sequential Loose-Routed requests later in the
> dialogue.
> 3) Just before you relay the request over UDP, call the force_send_socket()
> function. For example:
> force_send_socket(udp:;
> Hope this helps.
> John Quick
> Smartvox Limited
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