Networking guides
13 guides in this topic.
Common port numbers and what they are used for
A reference list of the most common TCP and UDP port numbers, from 22 SSH and 443 HTTPS to 3389 RDP, with what each one does and which ones to keep closed.
Networking · 2 min readHow to trace the route to an IP address with traceroute
Use traceroute (tracert on Windows) to see every router between you and a server, find where lag or loss starts, and understand the results.
Networking · 2 min readHow to use ping to test your connection
Use the ping command to check whether a server is reachable and how fast your connection responds. Learn to read the results, latency and packet loss.
Networking · 2 min readWhat is a default gateway and how do you find it?
The default gateway is the router your device sends internet traffic to. What it does, how to find its IP on Windows, Mac, iPhone and Android, and fixes.
Networking · 2 min readWhat is a MAC address, and how is it different from an IP address?
A MAC address identifies a network card on your local network; an IP address identifies your connection online. The differences, and how to find both.
Networking · 2 min readWhat is DHCP and how does it assign IP addresses?
DHCP automatically gives every device on your network an IP address, gateway and DNS server. Learn how it works, what a lease is and how to fix DHCP problems.
Networking · 2 min readWhat is NAT (network address translation)?
NAT lets every device in your home share one public IP address. Learn how it works, the types of NAT, NAT types in gaming and how NAT affects security.
Networking · 2 min readWhat is port forwarding and how do you set it up?
Port forwarding lets devices on the internet reach a server, camera or game console in your home. Learn how it works, how to set it up and how to stay safe.
Networking · 3 min read192.168.1.1, 192.168.0.1 and 10.0.0.1: how to log in to your router
Open your router settings at 192.168.1.1, 192.168.0.1 or 10.0.0.1. Find your router's IP, log in, and fix the most common problems step by step.
Networking · 2 min readSubnet masks and CIDR notation explained
What a subnet mask like 255.255.255.0 means, how CIDR notation like /24 works, how many addresses each size holds, with a cheat sheet and examples.
Networking · 2 min readWhat is an ASN (Autonomous System Number)?
An ASN identifies a network that routes its own traffic on the internet, like an ISP or cloud provider. Learn what ASNs are and what yours says about you.
Networking · 2 min readWhat is CGNAT (carrier-grade NAT)?
With CGNAT your provider shares one public IPv4 address between many customers. Learn how to tell if you are behind CGNAT and how to work around it.
Networking · 2 min readWhat is localhost (127.0.0.1)?
Localhost and 127.0.0.1 always point to your own computer. Learn how the loopback address works, what developers use it for, and what ::1 means.