Re: Question on NAT usage and Record Route

I am solving my own issue here. I just found out that the tls module has a parameter connection_timeout that defaults to 10 minutes, this was executing on my long running calls and terminating them. Hopefully this thread can help someone else now and in the future 😊

/M
From: Martin Nyström <[email protected]>
Date: Friday, 29 May 2026 at 11:27
To: Kamailio (SER) - Users Mailing List <[email protected]>
Subject: Re: Question on NAT usage and Record Route

Answering myself I just noticed there are some tcp keep alive options available in the Cookbook.

tcp_keepalive = yes
tcp_keepidle=60
tcp_keepintvl=10

Is this the way to go?


/M
From: Martin Nyström via sr-users <[email protected]>
Date: Friday, 29 May 2026 at 11:01
To: Kamailio (SER) - Users Mailing List <[email protected]>
Cc: Martin Nyström <[email protected]>
Subject: [SR-Users] Question on NAT usage and Record Route


CAUTION: This email originated from outside the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.


HI,

Our outbound traffic from Kamailio pass via Amazon NAT Gateway. The issue is that the NAT Gateway provided by AWS clears its table after 350s. This causes INVITE refresh after 900s to fail because the PBX sends the SIP to the Amazon NAT Gateway source IP : port and it is dropped by the NAT Gateway since the session do no longer exists.

It appears we cannot change the AWS NAT Gateway timeout, so we either need to drastically reduce the timer setting which I do not want, or find another way.

Can we in the signalling tell the PBX to reply not to the source ip and port but instead directly to the Kamailio FQDN? I am thinking Record Route would solve this, but before I start fiddling with it I’d like some feedback from the experts if that is the way.

We’re using Kamailio 6.1 with 5061/TLS.

/M

__________________________________________________________
Kamailio - Users Mailing List - Non Commercial Discussions -- [email protected]
To unsubscribe send an email to [email protected]
Important: keep the mailing list in the recipients, do not reply only to the sender!