What should I know about IP address management systems?

The days when it was possible to track IP address assignments with a spreadsheet are long gone.

Today's networks have hundreds or thousands of devices -- with more added or removed every day. This makes an IP address management (IPAM) application necessary for any network except the smallest ones.

How does an IP address management system work?

IPAM systems integrate with Dynamic Host Configuration Protocol (DHCP) to assign each device either a static or dynamic IP address and record which device it assigns to which address. Below are examples of static vs. dynamic address assignments.

Static address. IPAM systems should assign a static address -- i.e., an address that does not change for an extended period -- to devices such as printers or web servers, as other devices need to connect to them.

Dynamic address. Workstations and similar devices receive dynamic addresses, which the IPAM software grants for a specific period or lease time. Workstation addresses can change, as workstations connect to websites, printers and other types of services, but no other device or service initiates a connection to them.

IPAM systems can also integrate with a DNS to maintain updated, alphabetical maps of printer and web server names with their IP addresses. The systems also integrate with network inventory software that can track everything connected to the internet and can detect devices added to the network.

More devices create challenges for IP address management systems

Wi-Fi increases the necessity of IPAM systems. When a Wi-Fi device enters a facility, it connects to a DHCP server, which grants it a dynamic address with a short lease. The server will renew that lease while the device stays in the facility, but the lease may expire when the device leaves.

As a result, the Wi-Fi device will often receive a different address every time it enters the building. It would be nearly impossible for an IT team to manually maintain an up-to-date record of Wi-Fi device addresses.

This makes an IP address management application necessary for any network except the smallest ones.

DHCP is configured with the number of addresses and devices allowed on each subnet. As the network grows, IT teams may need to add additional subnets and move devices from one subnet to another, which would require device addresses to change.

The IPAM system and DHCP server must coordinate to update addresses for devices that will move to the new subnet. DHCP manages leases, so the leases of moving devices can expire at the same time -- usually, late at night. The IPAM system then must simultaneously update its database with the new addresses.

A variety of vendors offer IPAM systems. Customers should examine each to determine which offering has the features their network requires.