Sitemap
A flat index of everything on the site. The machine-readable /sitemap.xml is used by search engines; this page is for humans (and human-shaped AI crawlers).
Core pages
Training programs
- All programs
- CCNA®
- CompTIA Network+ (N10-009)
- Fortinet NSE 4 / FCP FortiGate
- CCNP®
- Palo Alto Networks Essentials — PCCET
- Custom Training — Pick Your Topics
- Palo Alto PCNSA — PAN-OS Network Security Administrator
- Python for Network Engineers
- AI for Network Operations
- Cisco DevNet Associate Prep
- US Network Engineer Interview Sprint
For US-specific audiences
Interactive simulators (15)
- CDP / LLDP Neighbor Discovery
- DHCP DORA Simulator
- EIGRP Successor / FS Simulator
- EtherChannel LACP Simulator
- Extended ACL
- HSRP Failover Simulator
- IPv6 SLAAC Boot Simulator
- NAT / PAT Translation Walkthrough
- OSPF Neighborship
- Route Summarization / CIDR Aggregation
- Spanning Tree (STP)
- Standard ACL
- Subnetting Visualizer
- TCP Handshake Simulator
- VLAN + Trunk Frame Walkthrough
Hands-on CLI labs (38)
Live-console tasks grouped by CCNA domain. Build tasks start from an empty device; Fix tasks drop you into a broken network.
- Mock exam entry · Labs index
- Build Assign an IP to a router interface
- Build IPv6 basics: address an interface
- Build Save the running config to NVRAM
- Build Set hostname and enable secret
- Build Bundle two links with LACP
- Build Create a VLAN, assign an access port
- Build Force SW1 to be the STP root
- Build Harden a switchport with port-security
- Build Two switches, one VLAN, one trunk
- Fix A VLAN won’t cross the trunk
- Fix EtherChannel bundle never forms
- Fix STP elected the wrong root bridge
- Fix VLAN 10 and VLAN 20 hosts can’t reach each other
- Build Add a default route
- Build Add a static route
- Build Bring up OSPF on a 3-router triangle
- Build Inter-VLAN routing with SVIs
- Build Two routers, static routes, ping across
- Fix A remote LAN is unreachable — static route missing
- Fix HSRP failover never happens
- Fix Multi-area OSPF: area 1 can’t reach area 0
- Fix OSPF neighbor never comes up
- Build Configure a DHCP server pool
- Build Configure PAT (NAT overload)
- Build Make R1 the HSRP active router
- Fix Clients aren’t getting an IP from the DHCP server
- Fix NTP sync never reaches stratum
- Fix The LAN can’t reach the internet
- Build Apply an ACL inbound on an interface
- Build DHCP snooping + Dynamic ARP Inspection
- Build Dynamic ARP Inspection (DAI) — trust ports + validation
- Build Enable 802.1X on an access port
- Build Port Security + IP Source Guard
- Build Secure VTY lines for SSH only
- Build Write a standard numbered ACL
- Build Write an extended ACL
- Fix A blocked host still reaches the server
- Fix Port-security err-disabled a legitimate host
Blog (29)
- CDP vs LLDP — Cisco's Neighbor Discovery vs the Vendor-Neutral Way
- HSRP vs VRRP vs GLBP — Which First-Hop Redundancy for CCNA (and Real Networks)
- Cisco Wildcard Masks: ACLs & OSPF Without Confusion
- Cisco Trunking Best Practices (Without Causing Outages)
- Don't paste that config into ChatGPT — safe GenAI for netops
- BPDU Guard vs Root Guard vs Loop Guard — When to Use Which (CCNA)
- TCP 3-Way Handshake Explained — SYN, SYN-ACK, ACK (CCNA)
- CCNA vs AWS Advanced Networking — which one, when, and why
- CCNA vs Network+ — which for a US networking career in 2026
- OSPF timers, DR/BDR election, and why yours is stuck in EXSTART
- OSPF vs EIGRP — which one for CCNA and real US networking work
- Static routing — floating routes, admin distance, and defaults
- IPv6 for CCNA — SLAAC, EUI-64, and the boot sequence
- EtherChannel with LACP — bundling four links into one Port-channel
- Layer 2 hardening — Port Security, DHCP Snooping, and DAI in one lab
- Standard vs Extended ACL — which one to use when
- HSRP walkthrough — how default gateway redundancy actually works
- Spanning Tree root bridge election — the mental model
- Inter-VLAN Routing — SVIs vs Router-on-a-Stick (CCNA)
- DHCP — DORA, Scopes, and the ip helper-address Relay (CCNA)
- Layer 2 Security — DHCP Snooping, DAI, and IP Source Guard (CCNA)
- NAT & PAT — Inside Local, Inside Global, and Overload (CCNA)
- CCNA v2.0 (2027) — What's Changing in the 200-301 Exam
- Cisco ACLs — Implicit Deny, Wildcards, and the 10-Second Read
- VLANs Explained — Trunks, Access Ports, Native VLANs (CCNA Tutorial)
- OSPF in 12 Minutes — The Mental Model Before the Commands (CCNA)
- 'My Trunk Won't Pass VLAN 20' — A 6-Step Debug Workflow (CCNA)
- The Free Certificates to Earn Before Your CCNA
- Subnetting in Your Head — The Magic-Number Trick (CCNA)
Also available as RSS.
Topic library (129)
- 802.1X — Port-Based Network Access Control
- AAA · RADIUS & TACACS+
- Access Control Lists (ACLs)
- Access Point Operating Modes
- AI & ML in Network Operations
- Ansible for Network Engineers
- ARP — Address Resolution Protocol
- BFD — Bidirectional Forwarding Detection for Fast Failover
- BGP Basics
- BGP Best-Path Selection — The Full 13-Step Order
- BGP Communities — Tags for Traffic Engineering + Well-Known Values
- BGP Route Reflectors — Scaling iBGP Beyond Full-Mesh
- BPDU Guard & Root Guard
- Business Continuity Metrics — RPO, RTO, MTBF, MTTR + Site Types
- Cable Connector Types — Copper, Fiber, Coax
- Cabling & Media Standards
- Catalyst Boot Process
- CDP & LLDP — Neighbor Discovery
- Cisco AnyConnect / Remote Access VPN
- Cisco DNA Center / Catalyst Center
- Cisco IOS Device Management
- Cisco IOS File System
- Cisco ISE Basics
- Cisco StackWise Virtual (SVL) — Two Chassis as One Logical Switch
- Cisco Zone-Based Firewall (ZBFW) — Zones, Zone-Pairs, Policy-Maps
- Common Network Attacks — On-Path, DNS Poisoning, DDoS, Deauth
- Common Ports and Protocols — N10-009 Reference Table
- CoPP — Control Plane Policing
- Cybersecurity Threats & Mitigation
- Default Routing
- DHCP — Dynamic Host Configuration Protocol
- DHCP Relay & IP Helper
- DHCP Snooping
- DNS — Domain Name System
- Dynamic ARP Inspection (DAI)
- EEM — Embedded Event Manager Applets and Scripts
- EIGRP
- Encryption Fundamentals
- EtherChannel (Link Aggregation)
- FHRP — HSRP, VRRP & GLBP
- FortiGate Architecture — FortiOS, VDOMs, and the Session Table
- FortiGate Firewall Policies — Structure, Order, NAT Inline
- FortiGate FSSO — Fortinet Single Sign-On
- FortiGate HA — FGCP Active-Passive and Active-Active
- FortiGate IPsec VPN — Site-to-Site and Dial-Up
- FortiGate SD-WAN with Performance SLA
- FortiGate Security Profiles — AV, Web Filter, App Control, IPS
- FortiGate SSL VPN — Web Mode and Tunnel Mode
- GRE Tunnels
- gRPC & gNMI — Streaming Telemetry
- Hierarchical Network Design
- HSRP vs VRRP vs GLBP — FHRP Compared
- ICMP — Internet Control Message Protocol
- IGMP & IGMP Snooping
- Inter-VLAN Routing
- Interface & Cable Issues: Collisions, Errors, Duplex/Speed Mismatch
- IP Multicast Basics — Groups, IGMP, PIM Sparse Mode, RP
- IP SLA — Cisco's Active Network Measurement + Track Object Integration
- IP Source Guard (IPSG)
- IPv4 Addressing
- IPv6 Address Types: Unicast, Anycast, Multicast, and EUI-64
- IPv6 Basics
- IPv6 First-Hop Security — RA Guard, DHCPv6 Guard, ND Inspection
- IPv6 Routing — Static & OSPFv3
- IPv6 SLAAC & DHCPv6
- IPv6 Transition Mechanisms
- JSON, YAML & XML for Network Engineers
- Layer-3 Switch & SVI Routing
- LISP Basics — Locator/ID Separation Protocol
- MAC Address Table
- MACsec (IEEE 802.1AE) — Layer-2 Wire-Speed Encryption
- MPLS Basics
- MTU & Fragmentation
- NAT & PAT
- NETCONF & YANG
- NETCONF and RESTCONF — Model-Driven Network APIs
- NetFlow & Flow-Based Monitoring
- Network Topologies — Bus, Ring, Star, Mesh, Hybrid, Hub-and-Spoke
- Network Troubleshooting Methodology
- Network Virtualization & Containers
- NTP — Network Time Protocol
- NTP Authentication & Security
- OSI Model & TCP/IP
- OSPF Multi-Area
- OSPF Single-Area
- Password Policy: Management, Complexity, MFA, Certificates, Biometrics
- Password Recovery & Configuration Register
- Port Security
- Power over Ethernet (PoE)
- Private IPv4 Addressing (RFC 1918)
- Private VLANs (PVLAN)
- Python for Network Engineers
- QoS Basics
- QoS Marking & Queuing — DSCP, Trust Boundaries, LLQ, CBWFQ
- Rapid STP & MSTP
- REST APIs for Network Engineers
- Route Summarization
- Routing Decision Process
- SD-WAN Concepts
- SDN & Controller-Based Networking
- Security Program Elements: Awareness, Training, and Physical Access
- SNMP — Simple Network Management Protocol
- SPAN, RSPAN & ERSPAN — Port Mirroring
- Spanning Tree Protocol (STP)
- Spine-Leaf Architecture (Modern Data Center Topology)
- Static Routing
- Subnetting
- Switching Operation
- Syslog
- TCP 3-Way Handshake
- TCP Connection States
- TCP vs UDP
- TFTP and FTP: Network File Transfer Basics
- Trunks & 802.1Q Tagging
- Twisted-Pair Cable Categories — Cat 5, 5e, 6, 6a, 7, 8
- Verify IP Parameters on the Client OS (Windows / macOS / Linux)
- VLANs
- VPN Basics — IPsec & SSL
- VRF Basics — Virtual Routing and Forwarding
- VTP — VLAN Trunking Protocol
- VXLAN Basics — VNI, VTEP, and Why Modern DCs Use It
- WAN Connection Types
- Wi-Fi 6, 6E, and 7 Features
- Wi-Fi Security — WEP, WPA, WPA2, WPA3
- Wireless LAN Basics
- Wireless RF Fundamentals
- Wireless Roaming — L2, L3, 802.11r Fast Transition, and OKC
- WLAN Architectures — Autonomous, Centralized (WLC), Cloud, Embedded
- WLC Deployment — Autonomous, Centralized, Cloud, and FlexConnect