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Straight-through cables connect PC to switch or router; crossover cables connect like to like. Here is the pinout, color code, and when Auto-MDIX makes it moot.

IP routing is how routers pick a path and forward packets between networks. Here is the routing table, next hop, and longest-prefix match in simple terms.

Enabling SSH on a Cisco router or switch takes a hostname, domain name, RSA keys, a local user, and vty line login. Here is the full config plus verification.

Fifty Cisco IOS commands every network admin and CCNA candidate should have in muscle memory, grouped by config, interface, routing, security, and troubleshooting.

SVIs (Switch Virtual Interfaces) are logical VLAN interfaces that enable a Layer 3 switch to route between VLANs and provide management access. Master SVI creation, IP routing enablement, and troubleshooting SVI states.

show interface status tells you more than up/down. Here are five tips for reading it quickly: port status, VLAN, speed/duplex, errdisable, and description use.