thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Collaboration, Voice & AV · Intermediate

SIP over TLS (SIPS)

Securing SIP signaling with TLS, normally on TCP port 5061, to provide confidentiality, integrity and authentication.

Definition

SIP over TLS protects headers and SDP, including SRTP keys exchanged with SDES, from eavesdropping and tampering. Each hop must trust the other's certificate, which requires CA chains and correct SAN or CN values. The sips: URI scheme requires TLS on every hop, while many systems use TLS hop by hop with sip: URIs.

Example

CUCM and CUBE exchange SIP over TLS on port 5061 using certificates signed by the enterprise CA.

Exam tip

SRTP keys sent with SDES are only protected if signaling is encrypted with TLS.

Related terms