What Is an Intranet (Private Network)?

Intro

An intranet is a private network that connects a limited set of devices inside one organization or household. It is different from the public internet, which connects everyone. At home this is your Wi‑Fi and the devices behind the router; in a company it is the office network that lives behind firewalls and access rules. We will keep the definitions practical and point you to the pages you can use right away.

Takeaway: an intranet is the private side of your network; the internet is the public side.

Definition

In simple terms, an intranet is any network that is intentionally scoped and controlled so only specific people and devices can use it. Most intranets use private IP addresses and sit behind a router or firewall. They may still reach the internet via NAT, but computers from the internet cannot directly route back in unless you open an entry point. Larger organizations extend intranets across sites with VPNs or VLANs without exposing internal services.

Takeaway: private addressing plus routing policy makes a network “intranet,” not total isolation from the internet.

Common Ranges

Private networks rely on reserved address ranges that never travel on the public internet. For IPv4 these are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. For IPv6, unique local addresses use fc00::/7, and most deployments pick fd00::/8. We maintain the quick-reference list with examples on the dedicated page; if you just need the numbers, jump to the private ranges page.

You can find the full table and brief notes on each block at Private IP Ranges.

Takeaway: private ranges are “do not route on the public internet” space for your intranet.

Why Use an Intranet

The first reason is safety and separation. Internal services like file shares, printers, dashboards, or databases should not be reachable from the public internet. The second reason is address conservation and simplicity: many devices can share one public IP through NAT. Finally, performance and governance improve when you keep local traffic local and enforce policies at a single perimeter.

Another major reason is collaboration. An intranet provides a shared, controlled space where employees or members can access common resources—internal wikis, project dashboards, shared printers, or file servers—without exposing them to the public internet. Because traffic stays inside, latency is low and availability is high. Centralized access control (LDAP, Active Directory, or single sign-on) also makes it easier for teams to work together securely and consistently. This is why intranets are often described as a backbone for cooperation inside organizations. This is also where NAT helps by connecting the private intranet to the public internet without exposing every internal host.

⚠️ Remember that private IPs do not automatically encrypt anything, and NAT is not a firewall by itself. You still need authentication and TLS when data is sensitive.

Takeaway: an intranet reduces exposure and complexity, but you still need proper security controls.

Intranet vs Internet

The internet uses globally unique public IPs so anyone can reach a service. An intranet uses private IPs and routing rules so only insiders can reach services. For a side-by-side comparison, see Intranet vs Internet.

To check quickly, see Find My IP. For address formats, see IPv4 vs IPv6.

Takeaway: private stays inside; public is globally reachable, with NAT bridging the two for outbound traffic.

Tiny FAQ

Takeaway: “private” controls reachability; it is not a magic cloak for internet privacy.

Wrap‑up / Next Steps

An intranet is a controlled, private network where your internal devices and services live. It improves safety, simplifies addressing, and keeps local traffic local, while using NAT to talk to the wider internet when needed. For a deeper dive into how NAT works and why it is so common, see What Is NAT. If you want the exact address blocks to use in your home or office, go to Private IP Ranges. If you are curious why addresses look different, read IPv4 vs IPv6.

Takeaway: think of the intranet as your private neighborhood and the internet as the global city; good fences and clear signs make both work better.