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Network Buddies Pro

Engineer mode: set up real networks

Network Stories explain the “what” and the “why”. Pro shows you how to configure it, how to check it, and how to fix it when it breaks. It is split into Layer 2 and Layer 3, and every lesson has a topology diagram, Cisco IOS-style commands, a guide to reading show output and a CLI Lab (a simulated terminal).

13 lessons · 1 ready to read

Layer 2 Pro

Dive into the world of the Switch with Octo: VLANs, STP, EtherChannel and Layer 2 security.

  1. Layer 2 Planned VLAN and Trunk Deep Dive: 802.1Q, Native VLAN, DTP and VTP A Frame on a Trunk has no tag. How does the Switch know which VLAN it belongs to? OctoPip
  2. Layer 2 Includes CLI Lab STP Deep Dive: Rapid PVST+ and BPDU Guard Someone plugged an old Switch into the living-room wall. Why is the whole house's traffic now detouring through it? OctoMacPip CCNA 200-301 · 2.5
  3. Layer 2 Planned EtherChannel: LACP, PAgP and Load Balancing Two cables are bundled together, so why does one big file still only get the speed of one cable? OctoPip
  4. Layer 2 Planned Layer 2 Security: Port Security, DHCP Snooping and DAI What happens to the whole house if someone plugs a fake DHCP Server into the living room? OctoMac
  5. Layer 2 Planned CDP and LLDP: How Devices Get to Know Their Neighbours Without opening the cabinet, how can you tell which device is on the other end of this cable? OctoMac

Layer 3 Pro

Dive into the world of the Router with Rue: routing basics, OSPF, FHRP, ACLs, IPv6 and BGP.

  1. Layer 3 Planned Routing Decisions: Longest Prefix Match, Administrative Distance and Metric Three routes in the Routing Table all reach the destination. Which one will Rue pick? RuePip
  2. Layer 3 Planned Static Routes and Floating Static Routes When the main line goes down, how does the backup line take over automatically without stealing the main line's job? RuePip
  3. Layer 3 Planned OSPF Deep Dive: Neighbor States, DR/BDR, Areas and LSAs The two Routers are connected properly, so why is OSPF stuck in EXSTART? RueProfessor Arpa
  4. Layer 3 Planned FHRP (First Hop Redundancy Protocol): HSRP and VRRP You can only enter one Default Gateway address, so how do two Routers take turns on duty? RueMac
  5. Layer 3 Planned NAT/PAT Deep Dive and DHCP Relay The DHCP Server is in another Subnet and Broadcasts cannot cross a Router, so how does a computer get its address? RuePip
  6. Layer 3 Planned ACL Deep Dive: Standard, Extended and Wildcard Masks What is 0.0.0.255? Why is an ACL mask the exact opposite of a Subnet Mask? RuePip
  7. Layer 3 Planned IPv6 in Practice: SLAAC, NDP and OSPFv3 Without DHCP, how does an IPv6 device come up with an address on its own? RueMac
  8. Layer 3 Planned BGP Basics: AS, eBGP and How the Internet Connects The Internet has no boss. How do tens of thousands of networks agree on which path to take? RueProfessor Arpa