[SR-Users] Kamailio like SBC with Teams

Thu Apr 16 09:19:25 CEST 2020

Hello good morning ... I am new to this list and I was starting to mess
with Kamailio, mainly to set it up as SBC against Teams, in this case.

But I can't get it to work for me. If I launch a call from the Teams, in
the Kamailio I see:

1.- In syslog:

Apr 15 11:11:41 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[ip_addr.c:243]: print_ip(): tcpconn_new: new tcp connection: 52.114.7.24
Apr 15 11:11:41 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[tcp_main.c:1073]: tcpconn_new(): tcpconn_new: on port 4160, type 3
Apr 15 11:11:41 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[tcp_main.c:1382]: tcpconn_add(): tcpconn_add: hashes: 171:1857:1187, 30
Apr 15 11:11:41 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[io_wait.h:388]: io_watch_add(): DBG: io_watch_add(0xa1f240, 23, 2,
0x7f90f2438f80), fd_no=17
Apr 15 11:11:41 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[io_wait.h:610]: io_watch_del(): DBG: io_watch_del (0xa1f240, 23, -1, 0x0)
fd_no=18 called
Apr 15 11:11:41 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[tcp_main.c:4219]: handle_tcpconn_ev(): tcp: DBG: sending to child, events 1
Apr 15 11:11:41 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[tcp_main.c:3902]: send2child(): selected tcp worker 1 10(23159) for
activity on [tls:SBC_IP:5061], 0x7f90f2438f80
Apr 15 11:11:41 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_read.c:1507]: handle_io(): received n=8 con=0x7f90f2438f80, fd=9
Apr 15 11:11:41 vps793907 kamailio[23122]: 10(23159) DEBUG: tls
[tls_server.c:184]: tls_complete_init(): Using TLS domain TLSs<default>
Apr 15 11:11:41 vps793907 kamailio[23122]: 10(23159) DEBUG: tls
[tls_domain.c:700]: sr_ssl_ctx_info_callback(): SSL handshake started
Apr 15 11:11:41 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_main.c:2516]: tcpconn_do_send(): tcp_send: sending...
Apr 15 11:11:41 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_main.c:2550]: tcpconn_do_send(): tcp_send: after real write: c=
0x7f90f2438f80 n=1468 fd=9
Apr 15 11:11:41 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_main.c:2551]: tcpconn_do_send(): tcp_send: buf=
Apr 15 11:11:41 vps793907 kamailio[23122]: #026#003#003
Apr 15 11:11:41 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[io_wait.h:388]: io_watch_add(): DBG: io_watch_add(0x9c1700, 9, 2,
0x7f90f2438f80), fd_no=1
Apr 15 11:11:42 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_read.c:296]: tcp_read_data(): EOF on 0x7f90f2438f80, FD 9
Apr 15 11:11:42 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_read.c:1291]: tcp_read_req(): tcp_read_req: EOF
Apr 15 11:11:42 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[io_wait.h:610]: io_watch_del(): DBG: io_watch_del (0x9c1700, 9, -1, 0x10)
fd_no=2 called
Apr 15 11:11:42 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_read.c:1434]: release_tcpconn(): releasing con 0x7f90f2438f80, state
-1, fd=9, id=30
Apr 15 11:11:42 vps793907 kamailio[23122]: 10(23159) DEBUG: <core>
[tcp_read.c:1435]: release_tcpconn():  extra_data 0x7f90f2432b40
Apr 15 11:11:42 vps793907 kamailio[23122]: 13(23167) DEBUG: <core>
[tcp_main.c:3331]: handle_tcp_child(): handle_tcp_child: reader response=
7f90f2438f80, -1 from 1
Apr 15 11:11:42 vps793907 kamailio[23122]: 13(23167) DEBUG: tls
[tls_server.c:604]: tls_h_close(): Closing SSL connection 0x7f90f2432b40

2.- With TCPDUMP:

11:13:09.311797 IP SBC_IP .1024 > SBC_IP .eu.sip-tls: Flags [S], seq
261244614, win 64240, options [mss 1440,nop,wscale 8,nop,nop,sackOK],
length 0
11:13:09.311898 IP  SBC_IP .eu.sip-tls > 52.114.76.76.1024: Flags [S.], seq
812357247, ack 261244615, win 29200, options [mss
1460,nop,nop,sackOK,nop,wscale 7], length 0
11:13:09.340358 IP 52.114.76.76.1024 >  SBC_IP .eu.sip-tls: Flags [.], ack
1, win 2053, length 0
11:13:09.340560 IP 52.114.76.76.1024 > SBC_IP .eu.sip-tls: Flags [P.], seq
1:187, ack 1, win 2053, length 186
11:13:09.340578 IP SBC_IP .eu.sip-tls > 52.114.76.76.1024: Flags [.], ack
187, win 237, length 0
11:13:09.341361 IP SBC_IP .eu.sip-tls > 52.114.76.76.1024: Flags [P.], seq
1:1469, ack 187, win 237, length 1468
11:13:09.369606 IP 52.114.76.76.1024 > SBC_IP .eu.sip-tls: Flags [.], ack
1469, win 2053, length 0
11:13:12.451498 IP 52.114.7.24.1216 > SBC_IP .eu.sip-tls: Flags [S], seq
309084204, win 64240, options [mss 1440,nop,wscale 8,nop,nop,sackOK],
length 0
11:13:12.451587 IP SBC_IP .eu.sip-tls > 52.114.7.24.1216: Flags [S.], seq
3275066862, ack 309084205, win 29200, options [mss
1460,nop,nop,sackOK,nop,wscale 7], length 0
11:13:12.707119 IP 52.114.7.24.1216 > SBC_IP .eu.sip-tls: Flags [.], ack 1,
win 2053, length 0
11:13:12.707311 IP 52.114.7.24.1216 > SBC_IP .eu.sip-tls: Flags [P.], seq
1:187, ack 1, win 2053, length 186
11:13:12.707345 IP SBC_IP .eu.sip-tls > 52.114.7.24.1216: Flags [.], ack
187, win 237, length 0
11:13:12.708273 IP SBC_IP .eu.sip-tls > 52.114.7.24.1216: Flags [P.], seq
1:1469, ack 187, win 237, length 1468
11:13:12.965101 IP 52.114.7.24.1216 > SBC_IP .eu.sip-tls: Flags [.], ack
1469, win 2053, length 0
11:13:12.965156 IP 52.114.7.24.1216 > SBC_IP .eu.sip-tls: Flags [F.], seq
187, ack 1469, win 2053, length 0
11:13:12.965688 IP SBC_IP .eu.sip-tls > 52.114.7.24.1216: Flags [F.], seq
1469, ack 188, win 237, length 0
11:13:13.220871 IP 52.114.7.24.1216 > SBC_IP .eu.sip-tls: Flags [.], ack
1470, win 2053, length 0

I can't "receive" anything.

I have generated the certificates and configured in the tls.cfg of the
Kamailio:

[server:default]
method = TLSv1.2
verify_certificate = no
require_certificate = no
private_key = /etc/letsencrypt/ssl/cert.key
certificate = /etc/letsencrypt/ssl/cert.crt
ca_list = /etc/letsencrypt/ssl/ca.crt

Within Kamailio itself I have it configured to return a 200 KeepAlive to
Teams when it receives an OPTIONS:

event_route[tm:local-request] {

        if(is_method("OPTIONS") && $ru =~ "pstnhub.microsoft.com") {
               append_hf("Contact: <sip: SBC_DNS :5061;transport=tls>\r\n");
        }
        xlog("L_INFO", "Sent out tm request: $mb\n");
}

And I have measured the record_route for this new one:

record_route_preset(" SBC_DNS :5061;transport=tls", " SBC_IP :5061");

I have created a dispatcher.list:

# setid(integer) destination(sip uri) flags (integer, optional),
priority(int,opt), attrs (str,optional)
1:1:sip:sip.pstnhub.microsoft.com;transport=tls 0 3 socket=tls: SBC_IP
:5061;ping_from= sip:SBC_DNS
2:1:sip:sip2.pstnhub.microsoft.com;transport=tls 0 2 socket=tls: SBC_IP
:5061;ping_from=sip: SBC_DNS
3:1:sip:sip3.pstnhub.microsoft.com;transport=tls 0 1 socket=tls: SBC_IP
:5061;ping_from=sip: SBC_DNS
4:1:sip:sip-all.pstnhub.microsoft.com;transport=tls 0 1 socket=tls: SBC_IP
:5061;ping_from=sip: SBC_DNS

I think that one of the problems is that I do not send the OPTIONS to the
Teams well, since it is on their panel, it indicates that the SBC is
INACTIVE.

I don't know if you could help me straighten this out a bit ...

Thank you so much for everything..

a greeting
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