There are two important protocols required to get your network to forward multicast packets: IGMP and PIM. In this article, I’ll show you how to set up these protocols on your network and how to troubleshoot them. PIM (Protocol Independent Multicast) has two main versions called “dense-mode” and “sparse-mode.” There is also a “sparse-dense-mode,” which has features of both versions and is really just used to help to bootstrap a multicast network.

The cloud is here—and so are its acronyms. Since software as a service (SaaS) hit the world in 2001, the ‘as a service’ model has been extended to just about everything you can think of. Along the way, the definition has become a little muddied. It used to be that -aaS meant something delivered on a subscription basis via the cloud, without a physical component.

For many companies, the beginning of October is also the beginning of the fourth and final quarter of the fiscal year. In IT, it’s a time to prepare for the new year by defining our priorities and setting our budget. COVID-19 threw a wrench into all of our 2020 plans from last year and a lot has changed since then. But one thing that hasn’t changed is the need for a network monitoring system in your software stack.

Multicast networking is based on the simple concept that a single packet can be sent by a server and it will be received by many receivers. Multicast is different from broadcast because it’s more selective. Where broadcast packets are received by all receivers in a particular network segment (or broadcast domain), multicast packets are received only by receivers that want them. Also, multicast receivers can be distributed throughout a larger network behind routers.

When something goes wrong in your network, you often don’t find out about it until your users are affected. By then, you’re on the receiving end of an angry phone call and you’re left scrambling to identify the issue and understand its root cause. As soon as you hang up (if the affected user even lets you hang up), you’re in a race against the clock.

As COVID-19 cases began to rise around the world in March 2020, governments and businesses had no choice but to take extraordinary measures to flatten the curve. As an IT leader, you were likely tasked with helping entire companies transition to remote work all at once. Cubicles were replaced by home offices. Face-to-face meetings were replaced by video calls. Work performance was measured by tasks completed instead of hours worked. Digital connectivity became more important than ever before.

Network hardware failures. Internet outages. DDoS attacks. These are the types of disruptions you probably spend your time preparing to handle. But there’s another potential source of trouble that most IT pros think about much less frequently, and which happens far more often: employee offboarding. Whether an employee is leaving to pursue another opportunity or an employee is being terminated, you need to make sure your company’s network and data are secure.

By even casual observation, you’ll likely have noticed that there are several IP address ranges that are special, including: Anybody can use these “private” ranges for anything they like. But there are actually several other special ranges that have other special purposes. In this article, I’ll explain what they are and the purpose they serve. This is the “loopback” range. These are addresses that are assumed to be on the same device that’s sending the packet.

Whether you’re trying to troubleshoot a problem, defend against attacks, or simply optimize your environment, event logs are your best source of information. More than that, not logging or ignoring your logs is like not checking your blindspot when you’re changing lanes—sooner or later you’re going to seriously regret it because the effects will be disastrous.

Subnetting isn’t hard but I often see even experienced network engineers looking for subnet calculators or trying to count in binary on their fingers. So how about a quick primer? To understand subnets, remember what a subnet is and think about the IP address in binary. A subnet is a range of IP addresses. All the devices in the same subnet can communicate directly with one another without going through any routers.