Chapter 7 • IP Addressing

IPv4 & IPv6

Bit, byte, octet; public vs private; unicast / broadcast / multicast / anycast; IPv6 shorthand and special ranges. (Source: Ch.7)

IPv4 = 32 bits (dotted decimal) IPv6 = 128 bits (hex) Loopback: 127.0.0.1 / ::1 APIPA: 169.254.0.0/16
IPv4 Classes & Private Ranges
Class A
1–126 (/8). Private: 10.0.0.0 – 10.255.255.255.
Class B
128–191 (/16). Private: 172.16.0.0 – 172.31.255.255.
Class C
192–223 (/24). Private: 192.168.0.0 – 192.168.255.255.
D/E
224–239 (multicast), 240–255 (experimental).
IPv6 Essentials & Shorthand

8 groups of 4 hex digits. Drop leading zeros; compress one run of consecutive 0 blocks with ::. Example: 2001:0db8:3c4d:0012:0000:0000:1234:56ab → 2001:db8:3c4d:12::1234:56ab.

Global Unicast: 2000::/3 Unique Local: fc00::/7 Link-Local: fe80::/10 Multicast: ff00::/8 Loopback: ::1
Dual-stacking and tunneling (6to4, Teredo/Miredo) let IPv6 traverse IPv4 infrastructures.
IPv4 vs IPv6 space IPv4 (32 bits) IPv6 (128 bits) — astronomically larger space
IPv6 enables end-to-end addressing and simpler subnetting at scale.

Chapter 8 • Subnetting & Troubleshooting

NAT • PAT • CLI

NAT translates private inside addresses to public; PAT (overloading) multiplexes many hosts onto a single public IP via unique source ports.

NAT/PAT flow LAN (10.1.1.x) NAT Router Internet 10.1.1.1 10.1.1.2 10.1.1.3
Inside Local → Inside Global (your private → your public). Outside Local/Global describe the destination before/after translation.
Troubleshooting Flow (5 steps)
  1. Ping 127.0.0.1 (IP stack up?).
  2. Ping your own IP.
  3. Ping default gateway.
  4. Ping remote host.
  5. If all succeed but names fail → verify DNS settings.
Subnet Practice Interactive

Pick a prefix length to see mask, hosts, and address capacity.

Subnet Mask:
255.255.255.0
Usable Hosts:
254
Total Addresses:
256
Network/Broadcast:
—

Chapter 9 • IP Routing

Static vs Dynamic

Routers forward based on the routing table. Routes can be static (manual) or dynamic (learned via protocols).

Static Route
Admin-configured; predictable; no protocol overhead; does not auto-adapt to failures.
Dynamic Route
Learns paths automatically; adapts to change; uses protocol metrics and adjacencies.
Distance Vector
Chooses path primarily by hop count (e.g., RIP). Periodic updates.
Link State
Builds a full topology and runs SPF (e.g., OSPF). Faster convergence.
Hybrid
Mixes both approaches (e.g., EIGRP elements; BGP context between ASes).
Default route & Administrative Distance Router Routes 0.0.0.0/0 → ISP ISP / Internet AD ranks sources (e.g., Static < RIP AD); metrics pick best path within a protocol.

Chapter 10 • Routing Protocols

AD • Metrics • FHRP
Protocol Classes
  • Distance Vector (RIP) — hop-count metric; sends table periodically; max hop 15; RIPv2 supports VLSM.
  • Link State (OSPF) — neighbor discovery, full topology DB, Dijkstra SPF; cost = ref BW ÷ intf BW.
  • Hybrid (EIGRP, BGP) — EIGRP uses neighbor/topology/routing tables; BGP exchanges routes between ASes (EGP).
High Availability (First-Hop Redundancy)

HSRP (Cisco) and VRRP (standard) offer a virtual default gateway for resilience (group limits differ; HSRP ~16, VRRP ~255).

Quick Check • 6 Questions

Auto-scored

Keyboard: use arrow keys to select; press Grade to score.

1) Which IPv4 range is private? (one)


2) IPv6 link-local addresses start with… (one)


3) Correct compression of 2001:0db8:0000:0000:0000:0000:0000:0042 is…


4) Which tool shows IP–MAC mappings on Windows?


5) RIP is best described as…


6) A default route is typically written as…


Hands-On • Guided Troubleshooting

Practice Flow
  1. Run ipconfig /all — record IP, mask, gateway, DNS.
  2. Ping 127.0.0.1, then your IP, then gateway. Note where it fails.
  3. If ICMP works but names fail, test nslookup example.com and verify DNS.
  4. Use tracert 8.8.8.8 to visualize the path.