Our Edge Proxies support SIP-over-TLS transport, sometimes known as "best-effort TLS", as described in RFC 5630, Section 3.1.3 and elsewhere. We do not support SIPS or SIPS URIs (end-to-end TLS).
DNS Records
We support SRV and NAPTR record lookup to discover _sip._tls.your-domain.com host and port records, if the SRV method is selected in the PBX or Trunk configuration.
Encryption Standards
We only support TLS 1.2 (and above) using the following cipher suites:
ECDHE-RSA-AES256-GCM-SHA384
ECDHE-RSA-AES256-SHA384
ECDHE-RSA-AES256-SHA
AES256-GCM-SHA384
AES256-SHA256
AES256-SHA
ECDHE-RSA-AES128-GCM-SHA256
ECDHE-RSA-AES128-SHA256
ECDHE-RSA-AES128-SHA
AES128-GCM-SHA256
AES128-SHA256
AES128-SHA