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This is a subject that's very critical for you to understand. Without a solid fundamental knowledge of networking you're going to struggle to diagnose problems and implement even the most basic of solutions.

A network is defined by Wikipedia as:

A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are made up of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies. -

It's the "communication protocols" that are the thing you'll learn at this level of networking. You've previously looked at networking hardware but now it's time to look at the basic concepts surrounding the protocols which can be thought of as being the software side of things.

Basic Concepts

These are the concepts I highly recommend you study and understand before moving on to the advanced topics in this book.

Please do keep in mind that networking is a massive topic. I'm going to highlight the topics, below, that I feel you'll face on a (near) daily basis as you operate in a modern, Cloud or hybrid based environment. Even though I'm trying to help you take a "shortcut" using the 80/20 Principle the list is still big. Don't be put off by this! Take your time and work your way through the content.

  • Protocols
  • Addressing
  • Network Segmentation
  • Routing
  • LAN vs WAN vs MAN
  • Security
  • Availability
  • Command Line Tools


Topic Resource Location Link
TCP Wikipedia TCP
UDP Wikipedia UDP
ICMP Wikipedia ICMP
IP Wikipedia IP
DHCP Wikipedia DHCP
DNS Wikipedia DNS
HTTP Wikipedia HTTP
SSH Wikipedia SSH
RDP Wikipedia RDP
NAT Wikipedia NAT
PAT Wikipedia PAT

Network Segmentation

Topic Resource Location Link
VLAN Wikipedia VLAN
DMZ Wikipedia DMZ


Topic Resource Location Link
RIP Wikipedia RIP
BGP Wikipedia BGP
LAN Wikipedia LAN
MAN Wikipedia MAN
WAN Wikipedia WAN


Topic Resource Location Link
IPv4 Wikipedia IPv4
IPv6 Wikipedia IPv6
Subnetting Wikipedia Subnetwork
CIDR Wikipedia CIDR


Topic Resource Location Link
Firewalls Wikipedia Firewall
IDS Wikipedia IDS
IDPS Wikipedia IDPS
VPN Wikipedia VPN
mTLS Wikipedia Mutual Authentication


Topic Resource Location Link
High Availability Wikipedia High Availability
Load Balancing Wikipedia Load Balancer
Clustering Wikipedia Computer Cluster

Command Line Tools

Topic Resource Location Link
ping man ping
ifconfig man ifconfig
iptables man iptables
netstat man netstat
traceroute man traceroute
nslookup man nslookup
dig man dig
tcpdump man tcpdump
nmap man nmap


Now we're going to look at (cyber) security and learn some important basics.