It no longer looks like an issue related to  set_reply_no_connect() or
set_forward_no_connect() added by the commit you referenced. Those were
added to prevent attempting to connect to devices behind the nat (in
that case the device has to maintain the connection, otherwise nobody
can connect back to it) as well as prevent someone in the wild sending a
request then closing the connection, without waiting for the reply,
which is typically routed back to via, commonly with an ephemeral port.

The follow up commit I did it in master recently is no longer setting
the flag for requests within dialog, but I understand you have
connection problems for requests within dialog, am I right?


On 10.09.19 01:08, Anthony Joseph Messina wrote:
> I still ran into some trouble when one side was NAT'd.
> Am I correct in thinking that it would be undesirable to maintain a TCP/TLS 
> connection to an upstream TLS gateway that is using the well-known port 5061?
> I was thinking this may be a case for TCP_REUSEPORT and force_send_socket, 
> but 
> that seems a little complex seeing as I can just let Kamailio reconnect (when 
> necessary) rather than preventing the outbound TLS from connecting when it 
> would otherwise succeed.
> I'll try and work through more detailed configuration scenarios.  -A
> On Monday, September 9, 2019 2:12:07 AM CDT Daniel-Constantin Mierla wrote:
>> Hello,
>> I relaxed that condition to not connect on forwarding only for initial
>> requests going though nat. Can you test with latest master and see how
>> is going for your use case?
>> Cheers,
>> Daniel
>> On 09.09.19 02:00, Anthony Joseph Messina wrote:
>>> In preparation for the 5.3 release, I've been testing the following
>>> configuration change for TCP/TLS connections:
>>> 8bba208fe6ae7ccb4c92362b8c33f1530b9f56da
>>> route[REQINIT] {
>>>         # no connect for sending replies
>>>         set_reply_no_connect();
>>>         if(has_totag()) {
>>>                 # no connect for requests within dialog
>>>                 set_forward_no_connect();
>>>         }
>>> This change creates issues when a UAC TLS INVITE routes to an upstream
>>> gateway using TLS to port 5061 (via the LCR module).  Kamailio sends the
>>> initial outbound TLS connection from a local ephemeral port.  The TCPOPS
>>> tcp_keepalive_enable function issues keepalives from the local ephemeral
>>> port to the gateway port 5061:
>>> tcpops#tcpops.f.tcp_keepalive_enable
>>> Even so, the TLS connection eventually times out, after which in-dialog
>>> requests from the UAC are no longer able to reach the upstream gateway.
>>> ERROR: tm [../../core/forward.h:293]: msg_send_buffer(): tcp_send failed
>>> WARNING: tm [t_fwd.c:1570]: t_send_branch(): sending request on branch 0
>>> failed
>>> ERROR: sl [sl_funcs.c:372]: sl_reply_error(): stateless error reply used:
>>> Unfortunately error on sending to next hop occurred (477/SL)
>>> I figure I must be doing something wrong with my TCPOPS here.  Is a TLS
>>> connection to an upstream gateway supposed to be maintained throughout the
>>> duration of a call?

Daniel-Constantin Mierla -- --
Kamailio Advanced Training, Oct 21-23, 2019, Berlin, Germany --

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