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Asterisk SIP/TLS Transport

When using TLS the client will typically check the validity of the certificate chain. So that means you either need a certificate that is signed by one of the larger CAs, or if you use a self signed certificate you must install a copy of your CA certificate on the client.

So far this code has been tested with:

  • Asterisk as client and server (TLS and TCP)
  • Polycom Soundpoint IP Phones (TLS and TCP) - Polycom phones require that the host (ip or hostname) that is configured match the 'common name' in the certificate
  • Minisip Softphone (TLS and TCP)
  • Cisco IOS Gateways (TCP only)
  • SNOM 360 (TLS only)
  • Zoiper Biz Softphone (TLS and TCP)
sip.conf options
  • tlsenable=yes - Enable TLS server, default is no
  • tlsbindaddr=<ip address> - Specify IP address to bind TLS server to, default is
  • tlscertfile=</path/to/certificate> - The server's certificate file. Should include the key and certificate. This is mandatory if you're going to run a TLS server.
  • tlscafile=</path/to/certificate> - If the server you're connecting to uses a self signed certificate you should have their certificate installed here so the code can verify the authenticity of their certificate.
  • tlscapath=</path/to/ca/dir> - A directory full of CA certificates. The files must be named with the CA subject name hash value. (see man SSL_CTX_load_verify_locations for more info)
  • tlsdontverifyserver=yes - If set to yes, don't verify the servers certificate when acting as a client. If you don't have the server's CA certificate you can set this and it will connect without requiring tlscafile to be set. Default is no.
  • tlscipher=<SSL cipher string> - A string specifying which SSL ciphers to use or not use. A list of valid SSL cipher strings can be found at
Sample config

Here are the relevant bits of config for setting up TLS between 2 Asterisk servers. With server_a registering to server_b

On server_a:

On server_b:

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