What Are Reserved IP Addresses and How Do You Use Them?
What Are Reserved IP Addresses? Wondering if you need to reserve one or if it’s already taken care of for you? Well, a reserved IP is something you set aside for your own use and can be assigned to an instance or load balancer whenever you need it. In this article, we’ll dive deep into the world of reserved IP Addresses.
In the realm of Internet addressing architecture, the Internet Engineering Task Force (IETF) and the Internet Assigned Numbers Authority (IANA) have designated specific Internet Protocol (IP) addresses for special purposes.
Perhaps the most well-known reserved IP is 127.0.0.1, commonly known as the loopback address. This little gem is used for testing network adapters or integrated chips. Any data sent to 127.0.0.1 stays within your local system and won’t traverse the local network or the vast expanse of the public internet.
IP addresses serve as the backbone of any network, and that includes the vast landscape of the Internet. Yet, with countless randomly generated IP addresses out there, devices like routers crave a stable, easy-to-remember address for frequent access.
Adding to the complexity, we’ve got a finite number of IPv4 addresses to work with on the internet, making it quite the challenge to assign a unique IP to every single device connecting to the web. But fear not, this is where reserved IP addresses swoop in to save the day. They play a vital role in every network, turning administrative tasks into a far more predictable endeavour.
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What Is a Reserved IP Address?
A Reserved IP address is a specific IP address assigned exclusively to your account. Whether you use this Reserved IP for a device or not, it will remain available to you unless you decide to release it.
When you browse the internet and access websites, you’re actually connecting to servers identified by their IP addresses, which are masked behind user-friendly URLs (Uniform Resource Locators). However, not all IP addresses are equal. They are categorized into five classes, ranging from Class A to Class E. (Troubleshooting Guide: Your IP Address Has Been Temporarily Blocked)
Certain IP addresses from classes A, B, and C are set aside as private IP addresses, accessible only within localized networks like those in universities or offices. These private IP addresses serve the purpose of creating a distinct range of IPs within the already limited IPv4 address space. By using private IP addresses for each network, the demand for unique IP addresses globally can be significantly reduced.
For example, let’s consider your home Wi-Fi network or any local network. If you check your computer’s IP address, you’ll notice a number like 192.168.xx.xx. This differs from your global IP address, which is assigned to the router instead of individual devices. In case you need to find all IP addresses on your network, we’ve also covered how to do that when the need arises.
How Do You Use Reserved IP Addresses?
In most cases, reserving IP addresses on a network isn’t necessary since devices usually come with pre-configured IP addresses, allowing easy network access.
Yet, you have the flexibility to tinker with a specific subset of reserved IP addresses within your network. By doing so, you can manually assign “static” IP addresses to specific devices on your local network, and this can be accomplished through your router’s DHCP settings.
The precise steps to carry out this process may vary depending on the make, model, and network requirements of your router. Nevertheless, you will likely find these settings tucked away under IP assignment or DHCP server settings on your router.
Here’s how you can set a static IP Address using the Windows settings:
- Head to the Start menu search bar, type in ‘settings,’ and select the best match. Alternatively, press the Windows Key + I to launch the Settings menu.
- Then head to Network & Internet settings.
- Look for the Properties button. It’s right next to your connection settings.
- Scroll down and look for the IP assignment section. Then click on Edit.
- In the new Edit IP settings dialogue box, click on the scroll-down menu and select Manual.
- Toggle on the switch for the IPv4 button.
- Fill in all the network details here, including the IP address, Subnet mask, and Gateway, and then click on Save.
Commonly Reserved IP Addresses for IPv4 and IPv6
IPv4
| Address block | Address range | Address Range |
|---|---|---|
| 0.0.0.0/8 | 0.0.0.0–0.255.255.255 | Current network |
| 10.0.0.0/8 | 10.0.0.0–10.255.255.255 | Used for local communications within a private network. |
| 100.64.0.0/10 | 100.64.0.0–100.127.255.255 | Shared address space for communications between a service provider and its subscribers when using a carrier-grade NAT. |
| 127.0.0.0/8 | 127.0.0.0–127.255.255.255 | Used for loopback addresses to the local host. |
| 169.254.0.0/16 | 169.254.0.0–169.254.255.255 | Used for link-local addresses between two hosts on a single link when no IP address is otherwise specified, such as would have normally been retrieved from a DHCP server. |
| 172.16.0.0/12 | 172.16.0.0–172.31.255.255 | Used for local communications within a private network. |
| 192.0.0.0/24 | 192.0.0.0–192.0.0.255 | IETF Protocol Assignments, DS-Lite (/29). |
| 192.0.2.0/24 | 192.0.2.0–192.0.2.255 | Assigned as TEST-NET-1, documentation and examples. |
| 192.88.99.0/24 | 192.88.99.0–192.88.99.255 | Reserved. Formerly used for IPv6 to IPv4 relay |
| 192.168.0.0/16 | 192.168.0.0–192.168.255.255 | Used for local communications within a private network. |
| 198.18.0.0/15 | 198.18.0.0–198.19.255.255 | Used for benchmark testing of inter-network communications between two separate subnets. |
| 198.51.100.0/24 | 198.51.100.0–198.51.100.255 | Assigned as TEST-NET-2, documentation and examples. |
| 203.0.113.0/24 | 203.0.113.0–203.0.113.255 | Assigned as TEST-NET-3, documentation and examples. |
| 224.0.0.0/4 | 224.0.0.0–239.255.255.255 | In use for IP multicast. (Former Class D network.) |
| 233.252.0.0/24 | 233.252.0.0-233.252.0.255 | Assigned as MCAST-TEST-NET, documentation and examples. |
| 240.0.0.0/4 | 240.0.0.0–255.255.255.254 | Reserved for future use. (Former Class E network.) |
| 255.255.255.255/32 | 255.255.255.255 | Reserved for the “limited broadcast” destination address. |
IPv6
| Address block (CIDR) | Usage | Purpose |
|---|---|---|
| ::/128 | Software | Unspecified address |
| ::1/128 | Host | Loopback address |
| ::ffff:0:0/96 | Software | IPv4-mapped addresses |
| ::ffff:0:0:0/96 | Software | IPv4 translated addresses |
| 64:ff9b::/96 | Global Internet | IPv4/IPv6 translation |
| 64:ff9b:1::/48 | Private internets | IPv4/IPv6 translation |
| 100::/64 | Routing | Discard prefix |
| 2001:0000::/32 | Global Internet | Teredo tunnelling |
| 2001:20::/28 | Software | ORCHIDv2 |
| 2001:db8::/32 | Documentation | Addresses used in documentation and example source code |
| 2002::/16 | Global Internet | The 6to4 addressing scheme (deprecated) |
| fc00::/7 | Private internets | Unique local address |
| fe80::/64 from fe80::/10 | Link | Link-local address |
| ff00::/8 | Global Internet | Multicast address |
