networking

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Homelab Networking Basics

Jun 3, 2026

Homelab Networking Basics

Networking can seem daunting, but for a homelab, understanding a few core concepts will get you a long way. This post covers the essentials: IP addresses, subnets, and basic firewall rules.

Tip

Even if you plan to use a managed router, knowing these basics helps you troubleshoot and configure your devices more effectively.

IP Addresses: Your Device’s Identity

An IP address is like a street address for your device on a network. There are two main types you’ll encounter:

• IPv4: The most common, looks like 192.168.1.100. It’s a 32-bit number.
• IPv6: The newer standard, looks like 2001:0db8:85a3:0000:0000:8a2e:0370:7334. It’s a 128-bit number, designed to address the exhaustion of IPv4 addresses.

Most homelabs still primarily use IPv4, often with private IP address ranges (e.g., 192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8) that are not routable on the public internet.

Checking Your IP Address

On a Linux machine, you can check your IP address with ip addr:

ip addr show eth0

Example output:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.100/24 brd 192.168.1.255 scope global dynamic eth0
       valid_lft 86077sec preferred_lft 86077sec
    inet6 fe80::211:22ff:fe33:4455/64 scope link
       valid_lft forever preferred_lft forever

Here, 192.168.1.100 is the IPv4 address, and /24 indicates the subnet mask.

Subnets: Dividing Your Network

A subnet divides a larger network into smaller, more manageable segments. The subnet mask determines which part of an IP address identifies the network and which part identifies the host.

IP Address	Subnet Mask	Network Address	Host Address
192.168.1.100	255.255.255.0	192.168.1.0	0.0.0.100
10.0.0.50	255.255.0.0	10.0.0.0	0.0.0.50

In CIDR notation, /24 means the first 24 bits are for the network, and the remaining 8 bits are for hosts. This allows for 254 usable IP addresses (2^8 - 2).

Why Subnet?

• Organization: Group devices logically (e.g., servers, IoT, guests).
• Security: Isolate sensitive devices from less secure ones.
• Performance: Reduce broadcast traffic within segments.

Firewalls: Your Network’s Gatekeeper

A firewall controls incoming and outgoing network traffic based on predefined security rules. For Linux, ufw (Uncomplicated Firewall) is a user-friendly interface for iptables.

Basic UFW Commands

# Deny all incoming, allow all outgoing by default
sudo ufw default deny incoming
sudo ufw default allow outgoing

# Allow SSH (port 22)
sudo ufw allow ssh

# Allow HTTP (port 80) and HTTPS (port 443)
sudo ufw allow http
sudo ufw allow https

# Enable UFW
sudo ufw enable

# Check status
sudo ufw status verbose

Caution

Always allow SSH before enabling UFW if you are connected remotely, otherwise you will lose access to your server!

Example Scenario: Web Server

Let’s say you have a web server running on your homelab at 192.168.1.10 and you want to allow external access to it on ports 80 and 443.

sudo ufw allow from any to 192.168.1.10 port 80 proto tcp
sudo ufw allow from any to 192.168.1.10 port 443 proto tcp
sudo ufw reload

This explicitly allows traffic to those ports on that specific IP address.

Next Steps

With these basics, you can start planning your homelab network. Consider drawing a simple network diagram to visualize your devices and their IP addresses. As you grow, you might explore:

• VLANs for advanced network segmentation
• VPNs for secure remote access
• DNS servers for local name resolution

Happy homelabbing!

Tags:

• homelab
• networking
• linux