Re: Kamailio behind NAT

Daniel-Constantin Mierla via sr-users <[email protected]>
Newsgroups gmane.comp.voip.ser
Message-ID <[email protected]>
It is about setting the socket parameter inside the attributes (the
attrs column) -- see:

  -
https://www.kamailio.org/docs/modules/stable/modules/dispatcher.html#dispatcher.ex.attributes

Cheers,
Daniel

On 04.09.25 09:44, Martin Nyström wrote:
>
> We’re using the dispatcher with MySQL. Here’s the setid from kamcmd
> dispatcher.list, this dns resolves to the Asterisk local ip
> 10.2.5.206, are you saying I should use udp: instead of sip: for my
> DEST entry? Would that really make any difference?
>
>  
>
> SET: {
>
>                 ID: 100
>
>                 TARGETS: {
>
>                                 DEST: {
>
>                                                 URI:
> sip:rtp-media.opm-media-namespace:5080?transport=DNS
>
>                                                 FLAGS: AX
>
>                                                 PRIORITY: 0
>
>                                 }
>
>                 }
>
> }
>
>  
>
>  
>
>  
>
> /M
>
>  
>
> *From: *Daniel-Constantin Mierla <[email protected]>
> *Date: *Thursday, 4 September 2025 at 09:05
> *To: *Kamailio (SER) - Users Mailing List
> <[email protected]>, [email protected] <[email protected]>
> *Cc: *Martin Nyström <[email protected]>
> *Subject: *Re: [SR-Users] Re: Kamailio behind NAT
>
>
> 	
>
> *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.
>
>  
>
> In the dispatcher routing records, be sure you have the attribute
> socket=udp:localip:5080.
>
>  
>
> Cheers,
> Daniel
>
>  
>
>  
>
> On 03.09.25 13:03, Martin Nyström via sr-users wrote:
>
>     I did the suggested changes, I think. But the INVITE sent from
>     Kamailio to Asterisk still holds the external advertised DNS in
>     the RR.
>
>      
>
>     Here’s the INVITE sent to Asterisk from Kamailio:
>
>      
>
>     eth1  Out IP 10.3.124.192.5060 > 10.2.5.206.5080: SIP: INVITE
>     sip:[email protected] SIP/2.0
>
>     INVITE sip:[email protected] SIP/2.0
>
>     Record-Route:
>     <sip:sbc.coolcompany.com;lr;ftag=5914da19-6958-4b8f-b521-d74c78af6120>
>
>     Record-Route: <sip:sip-provider.com;lr=on>
>
>     Call-ID: [email protected]
>
>     CSeq: 25896 INVITE
>
>     From: <sip:[email protected]>
>     <mailto:sip:[email protected]>;tag=5914da19-6958-4b8f-b521-d74c78af6120
>
>     To: <sip:[email protected]>
>     <mailto:sip:[email protected]>
>
>     Contact: <sip:[email protected]:5080>
>     <mailto:sip:[email protected]:5080>
>
>     Via: SIP/2.0/UDP
>     sbc.coolcompany.com:5060;branch=z9hG4bKb32c.739784aeb0177ad4d3e181098a071abb.0;rport
>
>     Via: SIP/2.0/UDP
>     sip-provider.com;branch=z9hG4bKb32c.79821495565acb8af61a7ebecb22b26d.0
>
>     Via: SIP/2.0/UDP
>     sip-provider.com:5060;branch=z9hG4bK-323035-3a9c396118a108606e6234ff3013ed5b
>
>     Max-Forwards: 67
>
>     Content-Type: application/sdp
>
>     User-Agent: XXXX
>
>     Content-Length: 293
>
>      
>
>      
>
>     Asterisk attempts to reply to the BYE on the external IP:
>
>      
>
>     <--- Transmitting SIP request (616 bytes) to
>     UDP:sbc.coolcompany.com:5060 --->
>
>     BYE sip:[email protected]:5080 SIP/2.0
>
>     Via: SIP/2.0/UDP
>     10.2.5.206:5080;rport;branch=z9hG4bKPj917dd0c5-192b-457d-ae1a-ef693895e0c7
>
>     From: <sip:[email protected]>
>     <mailto:sip:[email protected]>;tag=1f88f783-83a4-419f-a7c3-3c37a40dada6
>
>     To: <sip:[email protected]>
>     <mailto:sip:[email protected]>;tag=3c6c6d47-8beb-4c71-a829-15138869defd
>
>     Call-ID: [email protected]
>
>     CSeq: 25915 BYE
>
>     Route:
>     <sip:sbc.coolcompany.com;lr;ftag=3c6c6d47-8beb-4c71-a829-15138869defd>
>
>     Route: <sip:x.x.x.x;lr>
>
>     Reason: Q.850;cause=16
>
>     Max-Forwards: 70
>
>     User-Agent: xxxx
>
>     Content-Length:  0
>
>      
>
>      
>
>      
>
>     Here’s again my dumbed down CFG with changes:
>
>      
>
>     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 <DOMAIN>:5060
>
>     listen=tcp:<LOCAL_IP>:5060 advertise <DOMAIN>:5060
>
>     listen=tls:<LOCAL_IP>:5061 advertise <DOMAIN>:5061
>
>      
>
>     # INFO: Asterisk gateway listening
>
>     listen=udp:<LOCAL_IP>:5080
>
>     listen=tcp:<LOCAL_IP>:5080
>
>     listen=tls:<LOCAL_IP>:5081
>
>      
>
>     local_rport=on
>
>      
>
>     mpath="/usr/local/lib/kamailio/modules_k/:/usr/lib/x86_64-linux-gnu/kamailio/modules/"
>
>      
>
>     loadmodule "rr.so"
>
>      
>
>     modparam("rr", "force_send_socket", 1)
>
>      
>
>     route {
>
>      
>
>                     route(FROM_PROVIDER);
>
>                     exit;
>
>      
>
>     }
>
>      
>
>     route[RELAY] {
>
>      
>
>                     if(!t_relay()) {
>
>      
>
>                                     sl_reply_error();
>
>      
>
>                     }
>
>      
>
>                     exit;
>
>      
>
>     }
>
>      
>
>     route[FROM_PROVIDER] {
>
>      
>
>                     # INFO: The Asterisk
>
>                     ds_select_dst(100, 4);            
>
>      
>
>                     if(!has_totag()) {
>
>                                     record_route();
>
>                     }             
>
>      
>
>                     route(RELAY);
>
>                     exit;
>
>      
>
>     }
>
>      
>
>      
>
>     /M
>
>      
>
>     *From: *Martin Nyström <[email protected]>
>     <mailto:[email protected]>
>     *Date: *Wednesday, 3 September 2025 at 10:59
>     *To: *[email protected] <[email protected]>
>     <mailto:[email protected]>, Kamailio (SER) - Users Mailing List
>     <[email protected]> <mailto:[email protected]>
>     *Subject: *Re: [SR-Users] Kamailio behind NAT
>
>     Using a different port for Asterisk is not a bad idea. I might
>     just try that. I will return with the results or any follow up
>     questions.
>
>      
>
>      
>
>      
>
>     /M
>
>      
>
>     *From: *Daniel-Constantin Mierla <[email protected]>
>     <mailto:[email protected]>
>     *Date: *Wednesday, 3 September 2025 at 10:54
>     *To: *Kamailio (SER) - Users Mailing List
>     <[email protected]> <mailto:[email protected]>
>     *Cc: *Martin Nyström <[email protected]>
>     <mailto:[email protected]>
>     *Subject: *Re: [SR-Users] Kamailio behind NAT
>
>
>     	
>
>     *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.
>
>      
>
>     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
>
>          
>
>         __________________________________________________________
>
>         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!
>
>      
>
>     -- 
>
>     Daniel-Constantin Mierla (@ asipto.com)
>
>     twitter.com/miconda -- linkedin.com/in/miconda
>
>     Kamailio Consultancy, Training and Development Services -- asipto.com
>
>
>
>     __________________________________________________________
>
>     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!
>
>  
>
> -- 
> Daniel-Constantin Mierla (@ asipto.com)
> twitter.com/miconda -- linkedin.com/in/miconda
> Kamailio Consultancy, Training and Development Services -- asipto.com

-- 
Daniel-Constantin Mierla (@ asipto.com)
twitter.com/miconda -- linkedin.com/in/miconda
Kamailio Consultancy, Training and Development Services -- asipto.com

__________________________________________________________
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