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Kamailio Linux Voice over IP

Kamailio 101 – Part 5- First Call

Making our first call between two registered endpoints on Kamailio.

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Kamailio Linux Voice over IP

Kamailio 101 – Part 4 – SIP Registrar

Setting up Kamailio as a SIP registrar to handle REGISTER messages.

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Kamailio Linux Voice over IP

Kamailio 101 – Part 3 – Routing Blocks & Structure

How to use routing blocks and structure your code in Kamailio.

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Kamailio Linux Voice over IP

Kamailio 101 – Part 2 – Installation & First Run

Installing Kamailio on Ubuntu, basic rules for wring config files and we respond to SIP messages!

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Kamailio Linux Voice over IP

Kamailio 101 – Part 1 – Introduction

Introducing Kamailio SIP Server & explaining it’s uses.

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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.

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RFCs & Standards Voice over IP

SIP REGISTER status & why it’s not what you think it is.

SIP Register status, expires and why it’s often misunderstood.

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RFCs & Standards Voice over IP

SIP Concepts – Record Routing

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

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RFCs & Standards Voice over IP

SDP – Session Description Protocol – Overview

Understanding the SDP protocol and how it’s used to negotiate and setup media sessions.

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Linux Voice over IP

RTPengine – Installation & Configuration

Installation & basic configuration of the Sipwise NGCP rtpengine

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RFCs & Standards Voice over IP

Why z9hG4bK?

Why does every SIP branch start with z9hG4bK?

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RFCs & Standards Voice over IP

SIP Via Header

What a Via header does, how to interpret it and how it’s used in SIP routing.

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Kamailio Linux Voice over IP

Kamailio Bytes – MySQL Database Backend for Module Config

Many Kamailio modules require, or have additional functionality, when you’re using a database backend. There’s a few options, but for this tutorial we’ll use a MySQL database backend. To begin with we’ll install MySQL & Kamailio, apt-get install kamailio* mysql-server Next we’ll want to configure the file called kamctlrc in which we’ll add our database […]

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RFCs & Standards Voice over IP

DTMF over IP – SIP INFO, Inband & RTP Events

DTMF’s implementation in VoIP and the 3 types of DTMF encoding (Inband, RTP Event and SIP INFO)

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RFCs & Standards Voice over IP

RFC2976 / RFC6086 – SIP INFO

SIP INFO was designed to carry session related information during a session. SIP was designed to setup and tear down sessions, with little thought given to what happens after the setup, but before the teardown. SIP INFO (RFC2976) was designed to fill this gap. (Obsoleted by RFC6086) It’s predominantly used now to carry DTMF info […]

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RFCs & Standards Voice over IP

RFC2833 – RTP Events

RFC2833 was designed to carry DTMF signalling, other tone signals and telephony events in RTP packets. This was later superseded by RFC4733, but everyone still referrers to this protocol as RFC2833, so I will too. RFC2833 a special RTP payload designed to carry DTMF signalling information, so it operates on the same source / destination […]

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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.