Ask any networking student which layer a router belongs to, and “Layer 3” is usually the first thing that comes to mind — but knowing the answer and actually understanding why it’s true are two different things. A router’s placement at Layer 3 isn’t arbitrary; it comes directly from what a router is built to... » read more
Somewhere in your device’s network settings, alongside your IP address, sits a value most people never think about until something stops connecting properly: the subnet mask. It’s not something you’ll usually need to touch, but knowing how to find it — and understanding what it actually tells you — comes in handy for troubleshooting, setting... » read more
Subnet masks are one of those things almost everyone in networking has to look up at some point, no matter how many times they’ve calculated one before — the difference between a /27 and a /28, or what wildcard mask corresponds to 255.255.255.192, just isn’t something most people carry around in working memory. This article... » read more
What a Subnet Mask Mismatch Actually Does to Your Network Before troubleshooting, it helps to understand exactly why an incorrect subnet mask causes the specific, often confusing symptoms it does. Devices use the subnet mask to decide where traffic should go. When a device sends data, it uses its own IP address and subnet mask... » read more
CIDR notation shows up everywhere in networking — from configuring a home router’s subnet to defining a cloud VPC’s address space — yet the slash number at the end of an IP address (like the /24 in 192.168.1.0/24) trips up even experienced administrators when they’re working outside their usual range of familiar values. This article... » read more
IPv6 was designed around the idea that every device could eventually have its own globally unique, publicly routable address — but that doesn’t mean the concept of a “private” IP address disappeared. IPv6 has its own dedicated private addressing scheme, called Unique Local Addresses (ULA), that serves a similar purpose to IPv4’s familiar 192.168.x.x and... » read more
If you’ve ever opened a router’s admin page and seen an address like 192.168.1.1, you’ve already encountered a Class C private IP address — it’s the default local network range on the vast majority of home routers and small business networks worldwide. This article covers exactly what that range is and where it comes from,... » read more
Search for “ARP protocol port number” and you’ll find a surprising number of confidently wrong answers — some list port 67, others guess at a made-up value, and plenty of certification study guides use this exact question as a trick to catch students who assume every protocol works the same way. The real answer is... » read more
Every time a device on your network sends data to another device using its IP address, something has to figure out which specific piece of hardware that IP actually belongs to — and that job falls to the Address Resolution Protocol, or ARP. It’s one of the quieter protocols in networking, working in the background... » read more