Learn how your network works.
Long-form, plain-English guides to the things IPFerret's tools show you: what an IP address is and who can see it, how DNS turns names into addresses, what your router is doing, and how packets find their way across the internet.
Every guide here is written from scratch for IPFerret, not stitched together from other sites. Each one takes a single question (why does my IP address change, what does a subnet mask actually do, can someone find me from my IP) and answers it the way you would explain it to a colleague: what is going on underneath, the numbers worked out, the mistakes people commonly make, and what to do next. Most run to 1,500–2,000 words, because the honest answer to a networking question usually needs that much room.
Where a guide describes something you can see on your own connection, it links to the IPFerret tool that shows it: your public IP and ISP, your DNS resolver, the headers your browser sends, or the path your traffic takes. Reading about NAT is one thing; seeing your router's public address next to your laptop's private one makes it stick. Each guide shows when it was first published and when it was last changed.
New to networking? Start with the four guides below, then pick a topic. If you only need a one-line definition, the glossary has short entries for the acronyms these guides use.
IP addresses
What an IP address is, the kinds there are, and how addresses are written and split up.
What is an IP address? (in plain English)
An IP address is the numeric label that identifies your device on a network so data knows where to go.
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Public vs private IP addresses (the difference, in plain English)
Every device you own has a private IP that only works inside your network, and shares one public IP with the rest of the internet.
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Static vs dynamic IP addresses (and when you actually need a static IP)
A dynamic IP is handed to you automatically and can change; a static IP stays put.
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Why does my IP address change?
Your IP address can change for several unrelated reasons, and it matters which IP is changing.
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IPv4 vs IPv6: the differences that actually matter
IPv4 gives the world about 4.3 billion addresses and it ran out.
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IPv6 address format explained
An IPv6 address is 128 bits written as eight groups of four hexadecimal digits.
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IPv6 in 2026 — where it stands, where it's stuck
IPv6 has been "ready" since 2012 and is now used for over 45% of internet traffic — but adoption is uneven, the IPv4 layer is not going away soon, and the rough edges…
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IP address classes (A, B, C, D, E) explained
Classful addressing carved IPv4 into fixed Class A, B, C, D and E blocks with hard-coded network boundaries.
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What is a subnet mask? Subnetting and CIDR notation explained
A subnet mask splits an IP address into a network portion and a host portion.
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What is localhost (127.0.0.1)?
localhost is your own machine, and 127.0.0.1 is the address it answers on.
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What is a MAC address? (The hardware address, in plain English)
A MAC address is the 48-bit hardware address burned into every network adapter — the layer-2 identifier that moves frames around your local network.
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Home networks and routers
The pieces between your device and the internet: router, gateway, DHCP, NAT and the fixes people actually need.
How to find your router's IP address (your default gateway)
Your router's IP address — its default gateway — is the address you type into a browser to reach the admin page, and the one every device on your network sends…
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What is a default gateway?
A default gateway is the device — almost always your router — that your computer hands packets to whenever the destination is outside your local subnet.
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How DHCP works
DHCP is the automatic plumbing that lets your phone join a Wi-Fi network and 'just work' seconds later.
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What is NAT (Network Address Translation)?
NAT lets a whole network of devices share a single public IP address.
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Port forwarding, explained
Port forwarding is the rule that lets the outside world reach a service inside your home network — and it is the workflow most likely to fail silently in 2026.
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What is ARP? (Address Resolution Protocol, in plain English)
ARP is the glue between IP addresses and MAC addresses on a local network.
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Wi-Fi vs Ethernet — why your ping is worse on wireless
Wi-Fi and Ethernet move the same IP packets but behave very differently at the physical layer — Ethernet is full-duplex on dedicated wire, Wi-Fi is half-duplex on…
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How to flush your DNS cache
Stale DNS records send you to the wrong server after a site moves or changes hosts.
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DNS and domains
How names turn into addresses, the record types, propagation, encrypted DNS and who owns a domain.
How DNS works
Type a domain in the address bar, the page loads — and 50 milliseconds later, a distributed directory built in 1983 has walked a tree of servers around the world to…
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DNS record types explained (A, AAAA, CNAME, MX, TXT, NS, and more)
A practical reference to the DNS record types you actually meet in a zone file: A and AAAA map names to addresses, CNAME aliases one name to another, MX routes mail,…
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What is DNS propagation? (and why DNS changes take time)
DNS propagation is the wait between changing a DNS record and the whole internet seeing the new value.
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DoH vs DoT — DNS encryption, two flavors
DoH and DoT both encrypt DNS so your ISP cannot read which sites you visit.
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What is a domain name? (and how it maps to an IP address)
A domain name is a human-friendly label that stands in for a numeric IP address.
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What is WHOIS? (The internet's registration directory, explained)
WHOIS is the internet's registration directory: it tells you who registered a domain, or which organisation holds a block of IP addresses.
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How the internet moves data
Protocols, ports and routing: from TCP/IP and the OSI model to ASNs, BGP and CDNs.
What is TCP/IP? (The protocol suite the internet runs on)
TCP/IP is the family of protocols that moves every packet across the internet.
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TCP vs UDP: what's the difference?
TCP and UDP are the two workhorse transport protocols that sit on top of IP.
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The OSI model explained (all 7 layers)
The OSI model is a 7-layer conceptual framework for how network functions stack up, from cables and bits at the bottom to HTTP and DNS at the top.
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What is ICMP? (The internet's error-message protocol)
ICMP is the control protocol of the IP suite: it carries error and status messages, not user data, and it has no ports.
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Common port numbers explained
A port is a 16-bit number that identifies which service a packet is meant for at a given IP address.
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What is latency? Ping, jitter, and why it matters more than speed
Latency is the round-trip time for a packet to reach a destination and come back, measured in milliseconds.
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How traceroute works
Traceroute uses an old IP-protocol trick (the TTL field) to map every router between you and a destination, but the output is easy to misread.
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What is an ASN (Autonomous System Number)?
An ASN is the globally unique number that identifies an Autonomous System — the network, or block of IP prefixes, run under a single routing policy by an ISP, cloud…
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BGP hijacking, in plain English
BGP hijacking is when one network announces IP routes that belong to another, sending some of the internet's traffic the wrong way.
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What is a CDN?
A CDN is a global mesh of edge servers that cache your content close to users, absorb DDoS traffic, and terminate TLS for you.
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TLS / HTTPS, in plain English
HTTPS is the lock icon you see in every modern browser.
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Privacy and security
What your IP address reveals, how to hide it, and how sites defend themselves by IP.
What does a website actually see about you?
When you load a website, your browser hands over a surprising amount of information — your IP, request headers, screen resolution, fonts, browser version, timezone,…
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What can someone actually do with your IP address?
Your IP address reveals your ISP and a rough, city-level location — not your name, your home address, or your identity.
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How to hide your IP address
Hiding your IP means masking your public address from the sites you visit.
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What is a VPN and how does it work?
A VPN is an encrypted tunnel between your device and a VPN server that relays your traffic, so websites see the server's IP instead of yours.
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VPN vs proxy vs Tor
All three reroute your traffic so the destination sees a different IP, but they diverge sharply on what they encrypt, who they hide from, and how they fail.
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What is a proxy server?
A proxy server is an intermediary that makes requests on your behalf.
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What is a firewall? (Network traffic filtering, in plain English)
A firewall filters network traffic against a set of rules, allowing or blocking each packet based on IP address, port, protocol, and connection state.
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What is a DDoS attack? (Distributed Denial of Service, explained)
A DDoS attack floods a target with traffic from many sources at once so legitimate users can't get through.
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IP reputation and blocklists
Every IP address on the internet carries a rolling reputation score that mail servers, CDNs, and corporate firewalls use to decide whether to trust traffic from it.
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Geo-IP gotchas for developers
Geo-IP libraries make 'what city is this user in?' look like a one-line answer.
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Rate limiting by IP — the right way
Rate-limiting by IP looks like a one-liner but the edge cases — CGNAT shared IPs, mobile carriers, IPv6, corporate proxies, X-Forwarded-For — are where deployments fail.
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