Hi all,

I’m still stuck with this even if I built a new VM to avoid any buggy configuration.

Some thoughts on this:

1. I have tried to change verify_certificate = no on my server section of tls.cfg, so ideally the remote certificate will not be verified, but this is not changing anything.

2. My Kamailio cluster is part of a DNS alias, but the alias is defined as alias=<myalias>:5061 in the Kamailio.cfg. Could this be affecting somehow the verification? My tls.cfg only has server:default and client:default section.

3. Every time I reload the configuration, the TLS info and debug messages for client and server are coherent with what I would expect from my tls.cfg:

INFO: tls [tls_domain.c:278]: fill_missing(): TLSs<default>: tls_method=20                                                               

INFO: tls [tls_domain.c:290]: fill_missing(): TLSs<default>: certificate='/usr/local/etc/kamailio/tls/myCert.pem'                  

INFO: tls [tls_domain.c:297]: fill_missing(): TLSs<default>: ca_list='/usr/local/etc/kamailio/tls/myCAfile.pem'                      

INFO: tls [tls_domain.c:304]: fill_missing(): TLSs<default>: crl='(null)'                                                                 

INFO: tls [tls_domain.c:308]: fill_missing(): TLSs<default>: require_certificate=1                                                       

INFO: tls [tls_domain.c:315]: fill_missing(): TLSs<default>: cipher_list='(null)'                                                         

INFO: tls [tls_domain.c:322]: fill_missing(): TLSs<default>: private_key='/usr/local/etc/kamailio/tls/myKey.pem'                   

INFO: tls [tls_domain.c:326]: fill_missing(): TLSs<default>: verify_certificate=1                                                         

INFO: tls [tls_domain.c:329]: fill_missing(): TLSs<default>: verify_depth=9                                                              

DEBUG: tls [tls_domain.c:968]: fix_domain(): using tls methods range: 20                                                                  

DEBUG: tls [tls_domain.c:566]: load_crl(): TLSs<default>: No CRL configured                                                              

INFO: tls [tls_domain.c:658]: set_verification(): TLSs<default>: Client MUST present valid certificate                                   

INFO: tls [tls_domain.c:278]: fill_missing(): TLSc<default>: tls_method=20                                                               

INFO: tls [tls_domain.c:290]: fill_missing(): TLSc<default>: certificate='/usr/local/etc/kamailio/tls/myCert.pem'                  

INFO: tls [tls_domain.c:297]: fill_missing(): TLSc<default>: ca_list='/usr/local/etc/kamailio/tls/myCAfile.pem'                      

INFO: tls [tls_domain.c:304]: fill_missing(): TLSc<default>: crl='(null)'                                                                

INFO: tls [tls_domain.c:308]: fill_missing(): TLSc<default>: require_certificate=1                                                        

INFO: tls [tls_domain.c:315]: fill_missing(): TLSc<default>: cipher_list='(null)'                                                        

INFO: tls [tls_domain.c:322]: fill_missing(): TLSc<default>: private_key='/usr/local/etc/kamailio/tls/myKey.pem'                    

INFO: tls [tls_domain.c:326]: fill_missing(): TLSc<default>: verify_certificate=1                                                        

INFO: tls [tls_domain.c:329]: fill_missing(): TLSc<default>: verify_depth=9                                                              

DEBUG: tls [tls_domain.c:968]: fix_domain(): using tls methods range: 20                                                                  

DEBUG: tls [tls_domain.c:566]: load_crl(): TLSc<default>: No CRL configured                                                              

INFO: tls [tls_domain.c:658]: set_verification(): TLSc<default>: Server MUST present valid certificate                                   

DEBUG: tls [tls_domain.c:1119]: load_private_key(): TLSs<default>: Key '/usr/local/etc/kamailio/tls/myKey.pem' successfuly loaded  

DEBUG: tls [tls_domain.c:1119]: load_private_key(): TLSc<default>: Key '/usr/local/etc/kamailio/tls/myKey.pem' successfuly loaded  

DEBUG: tls [tls_rpc.c:82]: tls_reload(): TLS configuration successfuly loaded        

4. When the first handshake begins after reloading, it goes to the TLSs default domain:

DEBUG: <core> [ip_addr.c:229]: print_ip(): tcpconn_new: new tcp connection: 188.185.115.181                                              

DEBUG: <core> [tcp_main.c:985]: tcpconn_new(): on port 56404, type 3                                                                      

DEBUG: <core> [tcp_main.c:1295]: tcpconn_add(): hashes: 2351:1920:1122, 168                                                              

DEBUG: <core> [io_wait.h:376]: io_watch_add(): DBG: io_watch_add(0xa25be0, 30, 2, 0x7ff243558420), fd_no=21                              

DEBUG: <core> [io_wait.h:598]: io_watch_del(): DBG: io_watch_del (0xa25be0, 30, -1, 0x0) fd_no=22 called                                 

DEBUG: <core> [tcp_main.c:4131]: handle_tcpconn_ev(): sending to child, events 1                                                          

DEBUG: <core> [tcp_main.c:3813]: send2child(): selected tcp worker 2 13(13472) for activity on [tls:<myLocalIP>:5061], 0x7ff243558420  

DEBUG: <core> [tcp_read.c:1566]: handle_io(): received n=8 con=0x7ff243558420, fd=8                                                      

DEBUG: tls [tls_server.c:197]: tls_complete_init(): completing tls connection initialization                                             

DEBUG: tls [tls_server.c:226]: tls_complete_init(): Using initial TLS domain TLSs<default> (dom 0x7ff242d79b40 ctx 0x7ff2430cc448 sn []) 

5. I wonder if anyone has configured this with Skype for Business 2015 lately? Any clue?

Cheers, Francisco.