When setting up a network in need of static IP addresses I've come across at least two ways of doing so.

A: Router/Gateway
In particular, on my Buffalo router, under DHCP Server, there is the option to add multiple MAC addresses and the ability to assign them an IP address.

B: On the Device itself
Configuring the static IP on the device itself via the network adapter settings on Windows.

Which makes more sense to use in what situation? Is one better/worse than the other?

  • 2
    The one case that has been missed so far is the case of a portable device (ie laptop). Manually configuring an address will me it is broken when the device is taken off-network. – Zoredache Oct 8 '13 at 16:39
up vote 22 down vote accepted

The main advantage of using DHCP reservations is that the assignment of a "static" IP address is managed centrally. This can be helpful for example if you are often rebuilding a particular computer or constantly changing the OS or if setting a "static" IP address is cumbersome (DirectTV DVR for example).

Using DHCP reservations is also handy if you ever need to migrate to a new subnet. In most cases then you just need to change the subnet on the router\DHCP server and all the clients will automatically be updated to the new subnet.

Lastly, using DHCP reservations is nice because you have a central place that you can go and lookup the IP address of a machine, provided the router\DHCP server allows you to note a name in addition to the IP address and MAC Address.

The down side to DHCP Reservations is that you have to know the MAC address, not a huge deal, but depending on the Router\DHCP Server and the computers OS it may be more time consuming that just setting a static address on the machine.

  • 3
    Good overview, nice answer. – mfinni Oct 8 '13 at 17:33
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    +1 - DHCP reservations are wonderful. Even if the device actually has a statically assigned address (because of brain-damage in the device or because it legitimately needs to be static) using reservations to track all your IP address assignments gives you a configuration repository that, by definition, cannot fall out of date (unlike spreadsheets, text files, etc). Having renumbered several networks that had DHCP servers configured this way I can definitely say that it's easier, too, than static address hell. – Evan Anderson Feb 15 '14 at 12:43
  • If you do have a device that requires a static ip to set manually, also setting a DHCP Reservation for it has one downside - from the router, it looks just like any other DHCP Reservation, but unlike other machines, modifcations from the router will not propagate. This can be easily overlooked and cause problems. – Kevin Feb 7 '17 at 5:02
  • sometimes a DHCP reservation is the only option :( – user2230470 Aug 15 '17 at 5:41

A is the only way to set a static IP address. The device itself is configuring its own IP address; that's a static address.

B, at the DHCP server (which might also be your router, but isn't always) is often known as a DHCP reservation. The terminology can vary, and it's like a static IP, but it really isn't. The device is set for DHCP, and then the DHCP server knows that the device's MAC should get a specific IP.

There is no C.

  • 1
    Ah, DHCP Reservation, thank you for the terminology. :) – Shaz Oct 8 '13 at 15:17
  • Welcome to the site. Please read the "Help" link at the top, and don't forget to accept an answer. – mfinni Oct 8 '13 at 15:35

The proper term is a Lease Reservation. This is where you set a specific address on your DHCP server for a MAC address. This is not like a static IP in the sense that, if there are no more addresses, and a node isn't using a reserved address, it will be given to another node if needed. So, in essence, with DHCP, there is no way to '100% guarantee' one particular address, but then again that's what DNS is for :-)

You probably won't run into this under normal circumstances, but it is worth mentioning.

one reason why reservations are safer than static assignment is if one device, usually a printer, is set static, it could a source of future booby traps. I came across a really nasty case of this issue. Some pinpad at a restaurant was set to static and then forgotten. When it was accidentally turned on, it started conflicting with a newer static assignment. The entire network was going nuts. The pinpads wouldn't say address conflict, like a computer, but do strange things. If an admin is setting a static assignment, he/she has no clue about every device on the network, which could span multiple floors. Because of this, a conflicting static assignment could be made. And when the old device comes back up. Bam! One time I was setting up a static IP on a printer (long story) and used some crazy number in the subnet to avoid "hitting" another static assignment. It's like playing battleship, in reverse. With reservations, it's like static assignments, but all the assignments are noted in one place. You don't have to run around configuring embedded devices. Just copy paste some text and done. P.S. I do understand that reservations are still using DHCP. The client still needs to have the DHCP service running on the device. For more scale check out IPAM.

  • +1 for "playing battleship, in reverse". – womble Sep 12 '17 at 4:11

Your question makes little sense. However, a lot depends on how you want to set your network up.

Personally, I always set static IPs to networking devices so they can be easily found and managed. The same goes for all stationary devices like desktops/workstations.

  • How are static IPs easy to find and manage? Your statement would make more sense if it began: "I always set dynamic IPs..." – Andy Gee Aug 20 at 1:58

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