Static Routing on Cisco IOS XE: Default, Floating, and Host Routes
Static routing is the first routing you ever configure and the last routing you stop using. Dynamic protocols get the
CCNA
Everything mapped to the CCNA 200-301 blueprint. Articles tagged CCNA cover the exam topics in the order you actually learn them, each one backed by a lab you can build yourself.
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Longest Prefix Match: How Routers Actually Choose Routes
Ask a room of engineers "which route wins?" and most reach straight for administrative distance. That is the
Administrative Distance: The Complete Table, Proven on a Live Lab
Administrative distance ranks how much a router trusts each source of routing information, and it is the reason a prefix installs via EIGRP when you expected OSPF. Here is the complete default table, the floating static design that depends on it, and a real CML capture of the same prefix...
How to Read the Cisco Routing Table (show ip route Line by Line)
The routing table is the single most important piece of state on a Cisco router, and show ip route is
CDP vs LLDP: What Each Protocol Sees and When to Use Both
Every switch and router quietly announces itself to its directly connected neighbors, and you can read those announcements to map
Verify IP Parameters on Windows, macOS, and Linux
Half of "the network is down" tickets end at the client. Before touching a switch, verify four things
Virtualization Fundamentals: VMs, Containers, and VRFs
CCNA objective 1.12 asks for "virtualization fundamentals: server virtualization, containers, and VRFs" - three technologies that all answer
Power over Ethernet (PoE): Standards, Classes, and the Budget That Bites
Every access point, IP phone, and security camera on your network probably has no power cable. Power over Ethernet delivers
Private IPv4 Addressing (RFC 1918): The Blocks, the Rules, the NAT
Three address blocks appear in virtually every network you will ever touch: 10.0.0.0/8, 172.16.0.
2-Tier vs 3-Tier vs Spine-Leaf: Network Topology Architectures
Ask why a campus network has an "access layer" or why data centers abandoned the tree design entirely,
Duplex Mismatch and Interface Errors: Find It in 10 Seconds
"The network is slow" tickets that turn out to be a duplex mismatch are a rite of passage.
How Switches Learn MAC Addresses: The CAM Table Explained
Every frame a switch forwards is a lookup in one table: the MAC address table (historically the CAM table). Understanding