Securing VoIP networks
Safe Call
© mipan, Fotolia
Eavesdropping on conversations on a LAN is easier than ever thanks to insecure VoIP installations. You don't need to bug restaurant booths or tap phone lines – standard Linux tools are all a hacker needs.
Many small to mid-sized enterprises simply connect their new VoIP systems to existing LANs. Road warriors call in via the Internet, and remote branches use a standard connection to reach the mother ship. Unfortunately, this kind of installation doesn't provide anything in the line of VoIP infrastructure security.
In this article, we look at some of the special concerns affecting VoIP and describe some strategies and optional protocols for protecting voice communications.
A Typical VoIP Connection
Session Initiation Protocol (SIP, RFC 3261) [1] is the most popular open VoIP standard for initiating, negotiating, and managing VoIP connections. In combination with Session Description Protocol (SDP, RFC 4566) [2], which handles audio or video codec negotiation, SIP transmits information about the connection between the calling parties. Once the connection is established, the parties send and receive data using the Realtime Transport Protocol (RTP) [3].
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
US / Canada
UK / Australia
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
TuxCare Announces Support for AlmaLinux 9.2
Thanks to TuxCare, AlmaLinux 9.2 (and soon version 9.6) now enjoys years of ongoing patching and compliance.
-
Go-Based Botnet Attacking IoT Devices
Using an SSH credential brute-force attack, the Go-based PumaBot is exploiting IoT devices everywhere.
-
Plasma 6.5 Promises Better Memory Optimization
With the stable Plasma 6.4 on the horizon, KDE has a few new tricks up its sleeve for Plasma 6.5.
-
KaOS 2025.05 Officially Qt5 Free
If you're a fan of independent Linux distributions, the team behind KaOS is proud to announce the latest iteration that includes kernel 6.14 and KDE's Plasma 6.3.5.
-
Linux Kernel 6.15 Now Available
The latest Linux kernel is now available with several new features/improvements and the usual bug fixes.
-
Microsoft Makes Surprising WSL Announcement
In a move that might surprise some users, Microsoft has made Windows Subsystem for Linux open source.
-
Red Hat Releases RHEL 10 Early
Red Hat quietly rolled out the official release of RHEL 10.0 a bit early.
-
openSUSE Joins End of 10
openSUSE has decided to not only join the End of 10 movement but it also will no longer support the Deepin Desktop Environment.
-
New Version of Flatpak Released
Flatpak 1.16.1 is now available as the latest, stable version with various improvements.
-
IBM Announces Powerhouse Linux Server
IBM has unleashed a seriously powerful Linux server with the LinuxONE Emperor 5.