Btw...I do call sl_reply_error() on relay fails.  Below is a sample block:

if (!t_relay())

{

     ....log some errors....

     sl_reply_error();

}

else

{

     ....log successful relay....

}


On Fri, Dec 8, 2017 at 9:15 AM, Andrew Chen <achen@fuze.com> wrote:
Hi Daniel,

Thanks for the response.  The question that's been raised by our engineers is how do we know the message that's put in the queue actually successfully been sent on the wire/network?  Have there been situations where it gets stuck in the queue and never sent out?

Thanks.
--Andy

On Fri, Dec 8, 2017 at 12:35 AM, Daniel-Constantin Mierla <miconda@gmail.com> wrote:
Hello,


On 08.12.17 02:23, Andrew Chen wrote:
> Hi all,
>
> So for a while now I've been working with our engineering team to
> troubleshoot these random events where the UPDATE message sent from
> the server never made it to the client side.  Here is the the topology:
>
> Server -(tcp)-> kamailio -(tls)-> client
>
> So looks pretty straight forward and I have logging messages stating
> t_relay() was successful in sending the message.
>
> The question is how do we know t_relay really successfully sent it? 
> Does it actually monitor the physical interface as it goes out?
>
>
t_relay() may return successful code if the message was put in the
writing queue. Later can be another log message if sending ended int a
transmission timeout. Do you have a failure_route set for such
t_relay()? If not, you can add one, it should be executed if sending fails.

Cheers,
Daniel

--
Daniel-Constantin Mierla
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio Advanced Training - www.asipto.com
Kamailio World Conference - May 14-16, 2018 - www.kamailioworld.com




--
Andy Chen
Sr. Telephony Lead Engineer
415 516 5535 (M)




--
Andy Chen
Sr. Telephony Lead Engineer
415 516 5535 (M)


*Confidentiality Notice: The information contained in this e-mail and any
attachments may be confidential. If you are not an intended recipient, you
are hereby notified that any dissemination, distribution or copying of this
e-mail is strictly prohibited. If you have received this e-mail in error,
please notify the sender and permanently delete the e-mail and any
attachments immediately. You should not retain, copy or use this e-mail or
any attachment for any purpose, nor disclose all or any part of the
contents to any other person. Thank you.*