As a system administrator, I’ve come to realize that knowing networking isn’t just a bonus skill—it’s absolutely essential. While I primarily deal with servers, Active Directory, Exchange, and backups, none of it works without solid network connectivity. That’s why I want to break down the basic networking concepts in a simple, layman-friendly way. This will help anyone new to IT—or even fellow sysadmins—understand why networking is the backbone of everything we do.
Why Networking Knowledge Is Crucial for Sysadmins
Here’s why I consider networking a core skill in my daily work:
- Troubleshooting: When a server or service goes down, I need to know if it’s a DNS issue, IP conflict, or broken route.
- Design & Deployment: Setting up a new domain controller, DHCP server, or firewall rule requires knowing how traffic flows.
- Security: A basic understanding of ports, firewalls, and subnets helps in hardening systems.
- Collaboration: I often work with network engineers. Speaking the same language helps avoid delays and misunderstandings.
Now let’s look at the networking basics from a very simple perspective.
Layman’s Understanding of IP Addressing and Related Concepts
🧠What Is an IP Address, Really?
Think of an IP address as a home address for your device on the network. It helps computers find and talk to each other.
A typical IPv4 address looks like this:192.168.1.10
It’s a 32-bit number represented in four sections (called octets), each ranging from 0 to 255:
192.168.1.10 = 11000000.10101000.00000001.00001010 (binary)
🎨 IP Address Classes (Class A, B, C,D,E)
Originally, IPs were grouped into classes to divide large and small networks:
| Class | Range (First Octet) | Default Subnet Mask | Use Case |
|---|---|---|---|
| A | 1 – 126 | 255.0.0.0 (/8) | Huge orgs or ISPs |
| B | 128 – 191 | 255.255.0.0 (/16) | Medium orgs, colleges |
| C | 192 – 223 | 255.255.255.0 (/24) | Small businesses |
| D | 224 – 239 | – (Multicast) | Streaming, conferencing |
| E | 240 – 255 | – (Experimental) | Research (rare) |
Example:192.168.1.1 is a Class C IP (used in most home/office networks).
🏠 Private vs Public IP Addresses
IP addresses come in two main types:
| Type | Used For | Examples |
|---|---|---|
| Private | Internal LAN communication | 10.x.x.x, 172.16.x.x – 172.31.x.x, 192.168.x.x |
| Public | Internet communication | 8.8.8.8, 142.250.190.14 (Google) |
- Private IPs are not accessible from the internet.
- Public IPs are assigned by ISPs and are routable globally.
Example:
Your laptop →192.168.1.10
Google DNS →8.8.8.8(Public)
🔄 Static vs Dynamic IP Addresses
- Static IP: Manually assigned, doesn’t change. Used for servers, printers, routers.
- Dynamic IP: Automatically assigned by a DHCP server. Used for user devices.
| Type | Assigned By | Use Case |
|---|---|---|
| Static | Manual | Servers, routers, printers |
| Dynamic | DHCP Server | PCs, laptops, phones |
Example:
Domain Controller → Static IP (192.168.1.100)
Office laptop → Dynamic IP (192.168.1.57today,192.168.1.61tomorrow)
🧮 Subnetting
Why Subnet?
To divide a network into smaller, organized sections.
Imagine a building floor plan:
- Entire floor = Full network
- Rooms = Subnets
Subnet Mask Basics
Subnet mask defines which part is network and which is host.
| Subnet Mask | CIDR | Max Hosts | Use Case |
|---|---|---|---|
| 255.255.255.0 | /24 | 254 | Small office LAN |
| 255.255.255.128 | /25 | 126 | Split network in half |
| 255.255.255.192 | /26 | 62 | Smaller segments |
Example:
Network:192.168.1.0/24
Subnet 1:192.168.1.0/25→ 126 usable IPs
Subnet 2:192.168.1.128/25→ another 126 IPs
Refer this link for Advanced Subnetting learning.
🚪 Gateway
A gateway is like the door out of your network. If your device wants to talk to the internet or another network, it uses the gateway.
Example:
Your PC: 192.168.1.50
Gateway: 192.168.1.1 → router or firewall that connects to the internet.
Router vs Switch
| Device | Function | Example |
|---|---|---|
| Router | Connects different networks (LAN ↔ Internet) | Your Wi-Fi router |
| Switch | Connects multiple devices inside a LAN | Connects PCs and servers in a rack |
A switch is like a multi-port hub that keeps traffic isolated and efficient. A router decides where traffic should go.
🔁 NAT (Network Address Translation)
Since private IPs can’t talk directly to the internet, NAT is used on routers to translate private IPs into the public IP.
Example:
Your PC →192.168.1.100
Router → translates it to203.0.113.5before sending to internet
🛠️ Network Troubleshooting Commands
Here are my go-to commands and what they do:
| Command | What It Does | Example |
|---|---|---|
ipconfig (Windows) | Shows IP config | ipconfig /all |
ping | Checks if a host is reachable | ping google.com |
tracert | Shows route packets take | tracert 8.8.8.8 |
nslookup | Resolves DNS name to IP | nslookup www.microsoft.com |
netstat | Shows active connections | netstat -an |
arp -a | Shows MAC-to-IP mappings | arp -a |
These help when I’m checking if DNS is resolving, if there’s a routing issue, or if a service is listening on a port.
🧾 Summary
As a system administrator, I’ve learned that basic networking knowledge is not optional—it’s fundamental. Here’s a quick recap:
- Understand what IP addresses are, how they’re classified, and how private/public IPs work.
- Know the difference between static and dynamic IPs, and why subnetting matters.
- Be clear about roles of a gateway, router, and switch.
- Master basic troubleshooting commands to quickly diagnose issues.
🔜 What Should I Learn Next in Networking?
If you’re like me and want to go deeper, here’s what I recommend next:
- OSI Model & TCP/IP Stack – Understand how data moves across the network.
- DHCP & DNS Deep Dive – Crucial for name resolution and IP management.
- VLANs & Trunking – Great for network segmentation.
- Firewalls, NAT & Port Forwarding – Key for security and remote access.
- Wireshark Basics – Start analyzing network traffic.
- Zero Trust & Network Security – Modern networking needs modern security.
Final Note
In the end, networking is not just for network engineers. As a sysadmin, it’s part of my day-to-day life. Whether I’m deploying a new server, fixing a broken login, or investigating slowness, networking plays a role. The more I understand it, the faster and better I can do my job.
If you’re starting out or growing in your IT career, don’t skip networking. It’ll save you time, headaches, and help you become a well-rounded admin.