New subject: What is a good strategy to build Kamailio <--> pbx

16 Aug 2020


      What are  your thoughts on  architecture  build of the  following scenarios.
The PBX doesn’t  support websockets and we want to use sip.js / jsSip.  (use Kama as wss:// SIP proxy)
PBX has direct PRI/sip Trunks/ DID control/ Voicemail.
PBX hosts SIP extensions.
UA --> Kamailio --> PBX
--------SCENARIO A.)  ------- Host SIP[xxxx] extensions on  Kama box  but same SIP extensions  are also on PBX [xxxx]
1.  Build some sort of control to register handle  kama to pbx …. (but reg  webclients)
Kama [1100]  SIP-PBX [1100]
Does kama act as the UA 1100  / registered   to PBX
What about UA to kamailio (do we do 1100a so UA-kama is 1100a)  but  kama  is  maintain  REG/status/  but  passing that IF client  is  online  ?
MWI (voicemail is hosted on PBX)  so how does that move through can it.
------- SCENARIO  B.) ------  Proxy all/ everything . use route[REGFW] Forward all REG to  PBX..
Issues  ----
MWI  (SIP notify  ?)
SIP Incoming CALL  incoming calls  to  work.  (if UA holds REG to outbound proxy on PBX  or )
DTMF (sipINFO) doesn’t work (I see it sending)
I noticed I crashed the PBX because all the SIP scanners started pounding my  Kamailio box after 2 days when  I added route[REGFW] it starting eating up SIP trunk channels on PBX  cause started forwarding everything.  Like it starting 4241@xxxxx.com 4242@xxxxx.com  .
Or  might need to look at fail2ban  pike module  to oget this but still  had issues I just don’t know where to look or code to fix on SCENARIO B
Snippets on  my testing .
route[REGFWD] {
                        if(!is_method("REGISTER"))
                        {
                        return;
                        }
$var(rip) = $sel(cfg_get.PBX.bindip);
        $uac_req(method)="REGISTER";
        $uac_req(ruri)="sip:" + $var(rip) + ":" + $sel(cfg_get.PBX.bindport);
        $uac_req(furi)="sip:" + $au + "@" + $var(rip);
        $uac_req(turi)="sip:" + $au + "@" + "kamaproxy";
        # $uac_req(turi)="sip:" + $au + "@" + $var(rip);
        $uac_req(hdrs)="Contact: <sip:" + $au + "@"
                                                + $sel(cfg_get.kamailio.bindip)
                                                + ":" + $sel(cfg_get.kamailio.bindport) + ">\r\n";
        if($sel(contact.expires) != $null)
                        $uac_req(hdrs)= $uac_req(hdrs) + "Expires: " + $sel(contact.expires) + "\r\n";
                        else
                        $uac_req(hdrs)= $uac_req(hdrs) + "Expires: " + $hdr(Expires) + "\r\n";
                        uac_req_send();
                        }
        #!endif
---------------
So this led me to extra security   should  I host SIP extensions on kamailio as an extra security but then what about  MWI/inbound then) or do I have 1100 on kama which mitel is 1100  but I pass all info from inbound.