Understanding IP Address Management (IPAM)

IP address management, or IPAM, is the process of breaking down your internal IP blocks and assigning them into segments. This allows users to better monitor their networks; should an erratic IP appear, the segmented IPs show exactly which IP segment the problem originates from. It makes issues easier to find and fix.

Why manage IPs? Benefits of managing IP addresses

Managing IP addresses has numerous benefits for a system or facility. To begin, it simplifies IPv4 and IPv6 addresses and the assignment process. It also helps promote efficient management and maintenance of IPs – the assignment and allocation, IP address statuses, the hostnames and hardware associated with each IP, and more. Managing IP addresses helps administrators keep track of each IP address segment and the potential issues in each grouping.

Furthermore, managing IPs decreases the risk of misconfigurations, overlapping subnets, and IP address conflicts by enforcing Fully Qualified Domain Name (FQDN), which shows the exact location of a domain name in the hierarchy of a DNS server. IP management helps secure IPs and IP assignments, helps detect threats to the IP system as a whole, and assists in maintaining network health. 

With proper IP address space management and IPAM software, you can easily connect to a server using the assigned IP address. For example, if you need to remote into the DHCP server while you're connected to the same network, you only need to remember the IP address of the server and not the name. These IPAM solutions increase network efficiency and network performance.

Example of IP address management

To better understand IP address management, take this scenario below. There are several different ways to consider examples like these, but this scenario will explain IP address management (IPAM) for a small network. Hypothetically, in this system, there is 1 external IP, 5 servers (static, and 1 handles DHCP), 10 printers (static), and 200 wired PCs or users.

The system exists in a brand-new facility, where no IPs have been assigned. Therefore, as the LAN administrator, you have just been told that your Internet connection is in place and ready to use.

Establishing an IP address management plan

You already know how many devices will be connected to your network in the beginning. Therefore, it’s now time to establish a plan. In this example, we’ll use the 192.168.1.x private IPs, since they are the most familiar.

Technically, your first IP is 192.168.1.0 and your last IP is 192.168.1.255, which gives you 256 IP addresses; since your first IP would actually start at .1 and the .255 IP is unusable, you have 254 available IPs.

Your 5 servers will get your first 5 IP addresses and should be assigned statically. Even though you can control static assignment in DHCP, you don’t want to risk the servers losing their IP addresses; as such, you don’t want to depend on DHCP for network address assignment.

The servers go as follows:

Server_1 (also your DHCP server): 192.168.1.1

Server_2: 192.168.1.2

Server_3: 192.168.1.3

Server_4: 192.168.1.4

Server_5: 192.168.1.5

You have to account for growth, so leave 192.168.1.6 through 192.168.1.9 open for future servers. Whether they’re physical or virtual servers, they’ll need an IP.

Using IPAM for growth

As established, you have 10 printers that will be used by multiple users. IPs in the next segment of the block can be statically assigned at the printer or via the DHCP server.

Every office has a primary printer, copier, fax machine, and the like; assign that device 192.168.1.10. If you know that Group 1 will use Printer 1, then assign Printer 1 192.168.1.11. Assign Printer 2 to Group 2 and give it 192.168.1.12. Continue that pattern through until 192.168.1.29.

When assigning devices IP addresses, consider how often the device will be used. Printers are frequently used and frequently bought; you may need more IP space for those than for fax machines, for example.

IP address management with multiple IPs

Finally, you also have 200 PCs that need to be hardwired to the LAN. Each also needs an IP.

Starting at .30 gives you 225 IPs to assign; start your DHCP at .40 through .254, which gives you 215 IPs in the address pool for users and leaves 10 IPs open in the lower range for device growth.

Understanding managed switches and unmanaged switches

When segmenting and managing IP addresses, it’s also important to understand managed and unmanaged switches.

Managed switches allow users to adjust each port on the switch to any setting. This allows them to manage and set up their networks while also monitoring how they function. It gives far greater control than an unmanaged switch, which essentially allows devices on a local area network (LAN) to communicate with each other without any user intervention.

Unmanaged switches work well on small networks where configuring additional settings would be unnecessary. However, managed switches perform better in large networks; if you’re a company like in the example above, you want a managed switch to make sure you have control over your network and IPs.

If you use managed switches, they require IPs, which is another thing to keep in mind when assigning addresses throughout your network. Assign them at the higher end of your IP spectrum so as to keep them out of the way, as they will not require expansion.

Using subnetting in IPAM

Subnets are logical subdivisions of larger networks. They work to achieve fast, efficient computer networks when managing IP addresses. It’s akin to dividing a building; the building has one IP address, which is the public IP. Each room, however, has its own private IP address.

Because IPAM can become complex, especially when dealing with hundreds of devices and PCs on a large network, subnetting is incredibly helpful to understand.

For example, 192.168.1.1 with a subnet of 255.255.255.0 is not on the same network as 192.168.2.1/255.255.255.0, even though they might be in the same building. However, if you change the third octet in the subnet to 0, it becomes 255.255.0.0.  Now 192.168.1.1/255.255.0.0 and 192.168.2.1/255.255.0.0 are on the same network. The 255 is sort of a true/false in simple terms.

Keeping networks separated can be complicated; however, subnetting and subnet calculators are a help.

Frequently asked questions

Who manages IP address space?

The Internet Assigned Numbers Authority (IANA) distributes IP address blocks, monitoring IP address space and ensuring we do not run out of space or addresses.

Who maintains IP addresses of domain names?

The Internet Corporation for Assigned Names and Numbers (ICANN) maintains the central repository for IP addresses and coordinates the IP address distribution for domain names. It also maintains over 180 million domain names.

Can two devices have the same IP address?

Two devices can share the same public IP address, but they cannot have the same private IP address on the same network without IP conflict. If you change your IP address, you can't use an IP already on your network or it will caue a conflict. Segmentation, subnetting, and local area networks help prevent two devices from sharing a private IP and coming into conflict.

Does a managed switch have an IP address?

Yes; managed switches have their own IP addresses. When setting up a network, it’s important to keep in mind whether you’ll be using a managed switch, as you need to account for the IP address it will take up.

Does an unmanaged switch have an IP address?

No, an unmanaged switch does not require an IP on a network.