LAN IP Management

Keeping your head together with LAN IP Management

Keeping your Local Area Network (LAN) understandable can eliminate confusion and headaches. To lay the foundation for good management, a few basic concepts need to be understood.

Computers, printers, and other devices on a network have a unique number assigned to them. This number is assigned by a router’s DHCP server. DHCP means Dynamic Host Configuration Protocol, When a new device is connected to the network it queries the router to obtain a unique number so other devices can find it on the network. The number is essentially an address on the LAN. The numbers are known as IP numbers — Internet Protocol numbers. They look this this: (in the 4 group version, known as IPv4)
or like this
2001:DB8:7654:3210:FEDC:BA98:7654:3210 (in the new 6 group format, known as IPv6)

Usually a simple LAN will use the 4 group version and the router will assign an unused IP number to the new device. The number that is assigned depends on how the router is configured. Nearly all routers offer the ability to create a pool of numbers that start at a certain number and end with a certain number. See the image below from an Asus router. If the router has it’s home IP address as then IP numbers assigned by the DHCP server will almost always begin with 10.1.10. If the starting number is, then new devices will end up with a final number always 100 or above, such as, Numbers assigned by the DHCP server are known as dynamic IP numbers — because the number associated with the device on the network could change for a few reasons (turning on, off, power outage, etc).

Many devices — such as computers and printers and cameras — have a configuration screen where the IP number can be preset. Numbers set in the device are known as static IP numbers. For example, a printer might have as a static IP number. The advantage of using static IP numbers for devices is that the address — the number — never changes.

A good management practice when using dynamic and static UP numbers is to start the dynamic IP number pool at 100 so all dynamic numbers are 100 or greater and have 3 digits — for fast recognition. Then set all static IP numbers to numbers less than 100. This segmentation helps prevent the same IP number being assigned to two devices, which will create havoc and confusion in the network.

For static IP numbers when there only a few devices, use the last number in increments of 5 or 10. For example:
printer 1 =
printer 2 =
printer 3 =

Spreading the numbers out creates easier recognition.

Grouping similar devices is also useful for static IP numbers. For example:

All IP cameras are in this range: through

All printers are in this range: through

Being consistent and systematic with IP numbers can go a long way in keeping all devices on a LAN working right and management is also less confusing.

Maintaining a spreadsheet on a local computer or in the cloud (such as Google Sheets) can help keep track of devices and provide fast lookups.