Secure SIP configuration settings for outbound calls

The various configuration settings that can be modified to influence secure SIP usage within outbound calls are described.

Certificate usage must have previously been set up as described in Secure SIP minimal configuration.

The following configuration parameter influences secure SIP usage within outbound calls:

Transport Protocol

Defines the default protocol that is used to make outbound calls when the sip: scheme is used. When the sips: scheme is used, a TLS (end-to-end) connection is used regardless of the setting of Transport Protocol, which has a default value of UDP. For more information, see Transport Protocol.

The use of the sip: scheme with Transport Protocol set to TLS guarantees the use of TLS only for the first hop within the total end-to-end connection. If end-to-end secure SIP is required, the sips: scheme must be used.