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Patch cables plugged into the ports of a desk network switch, with SMEnode Labs cyan fading in from the bottom-left corner.

Dynamic Trunking Protocol (DTP): Modes, Risks and Why You Turn It Off

Dynamic Trunking Protocol (DTP) explained: the 5 modes, which pairs form a trunk, how switch spoofing abuses it, and how to turn it off without an outage.
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A hand typing code on a laptop on a wooden desk, with SMEnode Labs cyan fading in from the bottom-left corner.

Python for Network Engineers: 10 Scripts That Automate Cisco Devices

Python for network engineers, done in code: 10 tested scripts for Cisco IOS with Netmiko, TextFSM, Jinja2 and RESTCONF, each mapped to the 200-901 exam.
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A Linux network configuration file open on a screen, showing an ethernet interface set to dhcp4 true, with SMEnode Labs cyan fading in from the bottom-left corner.

What Is APIPA? Why You’re Getting a 169.254 Address

What is APIPA? Why your PC picked a 169.254 address, the exact RFC 3927 range, how ARP probes work, a 7-step fix order and a CCNA lab to break on purpose.
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Person connecting Ethernet cable to a network device for DHCP configuration.

What Is DHCP? The DORA Process, Ports and Cisco Config

What is DHCP? The DORA process, why it's UDP 67 and 68 (and when it's 67 both ways), lease timers, relay, and Cisco IOS server config with a worked example.
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Technician working on network server with cables in a data centre.

VTP Explained: Why Most Networks Should Leave It Off

VTP (VLAN Trunking Protocol) explained: modes, versions, the revision number that wipes VLANs, DTP, exam coverage, and when to use transparent, off or v3.
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Network switch with Ethernet cables connected for data transfer.

EIGRP vs OSPF: Which to Run and Why

EIGRP vs OSPF on one topology: the metric maths, feasible successor, convergence, what CCNA v2.0 and ENCOR test, and a clear rule for which one to run.
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A single white network device mounted on a run of steel cable tray carrying bundled conduit across a concrete ceiling, with SMEnode Labs cyan entering from the bottom-left corner and easing out diagonally toward the top right.

Router on a Stick: Inter-VLAN Routing With One Interface

Router on a stick routes between VLANs on one Cisco interface. Full IOS config, the native VLAN line everyone forgets, verification, and the five failures that break it.
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Pale grey-blue network cables gathered into strapped bundles curving into a tall patch panel rack lit warm gold down its centre, with SMEnode Labs cyan entering from the bottom-left corner and easing out diagonally toward the top right.

EtherChannel and LACP: Bundling Links Without Breaking STP

LACP bundles physical links so spanning tree sees one port, not four. Config, active vs passive, and the STP cost trap when a member link fails.
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A white WiFi 6 home router on a sunlit wooden desk with a green cable plugged into its WAN port and a laptop behind it, with SMEnode Labs cyan entering from the bottom-left corner and easing out diagonally toward the top right.

What Is NAT? Static, Dynamic and PAT With Cisco Configs

What is NAT? Network Address Translation explained with working Cisco configs for static NAT, dynamic NAT and PAT, plus verify and troubleshooting commands.
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Network cables connected to a wall-mounted device with shadows on the wall.

BPDU Guard: What It Blocks and How to Recover an Err-Disabled Port

BPDU guard shuts a port the moment a rogue switch sends a BPDU. What it blocks, the config commands, and how to recover an err-disabled port.
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Technician testing network cables in a server room with a cable tester.

RSTP vs STP: Port Roles, States and Faster Convergence

RSTP converges in under a second where legacy STP takes 30 to 50. Port roles, the three port states, the proposal and agreement handshake, Cisco config, and a timed lab you can run tonight.
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Technician working with network cables in a data center.

Multiple Spanning Tree Protocol (MST): Config and When to Use It

Multiple spanning tree protocol maps many VLANs to a few STP instances. MST regions, IST and CIST, the full Cisco config, and when to pick it over Rapid PVST+.
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