Categories
Voice over IP

SIP Hold – With RFC6337

How SIP hold using RFC6336 is implemented and how it looks in production.

Categories
RFCs & Standards Voice over IP

SIP Supported & Require

Function of Supported & Require headers in SIP.

Categories
RFCs & Standards Voice over IP

SIP Route, Contact, From Headers – Which to use?

The rules for which headers to use when creating a SIP request and knowing where to route it.

Categories
RFCs & Standards Voice over IP

What is a SIP Registrar?

Explanation of what a SIP Registrar does, Contact header and Address on Record, and how it all fits together to route messages correctly.

Categories
RFCs & Standards Voice over IP

SIP Concepts – Record Routing

Explanation of Record-Routing, why it exists and how it’s used.

Categories
RFCs & Standards Voice over IP

Why z9hG4bK?

Why does every SIP branch start with z9hG4bK?

Categories
Linux Python RFCs & Standards Voice over IP

Reverse MD5 on SIP Auth

How the SIP Authentication mechanism works, and how we can reverse it to check the password we’re expecting is the encrypted value we’re seeing in captures.