Re: Kamailio behind NAT

Hello,

the simplest way is to listen on another port (e.g., 5080) and use that
socket to communicate with Asterisk. For that listen parameter, do not
set the advertise address. You can use $fs or force_send_socket() to
specify the socket to be used for sending out to Asterisk.

The alternative is to play in the config file with the function of the
rr module that allow you to set the address in the Record-/Route
headers, but it may increase the complexity of the config.

Cheers,
Daniel

On 03.09.25 10:42, Martin Nyström via sr-users wrote:
>
> Hello,
>
>  
>
> I am not successful in my attempts to configure my Kamailio to work
> behind NAT.
>
>  
>
> The flow of an incoming call is Provider (Internet) -> AWS
> LoadBalancer -> Kamailio -> Asterisk
>
>  
>
> Both the Kamailio and Asterisk is on the internal network. The issue I
> am having is that I need to add Record-Route to the traffic sent back
> towards the provider, but not to the Asterisk. Currently when I add
> the record_route() the header is sent to Asterisk which makes it reply
> to the Kamailio advertised external address for ACKs, BYEs etc.
>
>  
>
> I have dumbed down my Kamailio config as much as possible for this, to
> show what I am currently doing.
>
>  
>
>  
>
> debug=2
>
> log_stderror=yes
>
> fork=yes
>
> tcp_accept_no_cl=yes
>
> onsend_route_reply=yes
>
> pv_buffer_size=2048
>
> enable_tls=1
>
>  
>
> listen=udp:<LOCAL_IP>:5060 advertise <EXTERNAL_DOMAIN>:5060
>
> listen=tcp:<LOCAL_IP>:5060 advertise <EXTERNAL_DOMAIN>:5060
>
> listen=tls:<LOCAL_IP>:5061 advertise <EXTERNAL_DOMAIN>:5061
>
>  
>
> local_rport=on
>
>  
>
> mpath="/usr/local/lib/kamailio/modules_k/:/usr/lib/x86_64-linux-gnu/kamailio/modules/"
>
>  
>
> # MODULES
>
> loadmodule "..."
>
>  
>
> route {
>
>  
>
>                 route(FROM_PROVIDER);
>
>  
>
> }
>
>  
>
>  
>
> route[RELAY] {
>
>  
>
>                 if(!t_relay()) {
>
>  
>
>                                 sl_reply_error();
>
>  
>
>                 }
>
>  
>
>                 exit;
>
>  
>
> }
>
>  
>
> route[FROM_PROVIDER] {
>
>
>                # The Asterisk that should not receive the external dns
> in the record route header
>
>                 ds_select_dst(100, 4);
>
>  
>
>                 # INFO: This adds the Record-Route in all directions
>
>                 if(!has_totag()) {
>
>                                 record_route();
>
>                 }
>
>                                
>
>                 route(RELAY);
>
>                 exit;
>
>  
>
> }
>
>  
>
>  
>
>  
>
>  
>
>  
>
> /M
>
>
> __________________________________________________________
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-- 
Daniel-Constantin Mierla (@ asipto.com)
twitter.com/miconda -- linkedin.com/in/miconda
Kamailio Consultancy, Training and Development Services -- asipto.com

__________________________________________________________
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To unsubscribe send an email to [email protected]
Important: keep the mailing list in the recipients, do not reply only to the sender!