What are the hardware, software and network requirements for a new Domain Server with Windows Server 2003 for 100 users?

4 Answers 4


100 users is nothing even for an entry level server and a switched 100 Mbit/s network.

Best practice dictates:

  • A second domain controller for reliability
  • Reliable/redundant hardware (for example, not the glorified desktop tower servers)
  • 100 Mbit/s network card and network infrastructure
  • Antivirus.... see this site ad-nasuem!

Domain controllers by today's standards have very lightweight hardware and network requirements - yet they are perhaps the most vital part of your network hence go for reliability and redundancy (multiple power supplies, network cards 2nd server, etc...).

Given the broad scope of your question (to put it politely) it is hard to give any specific advice - are they also going to be file servers, DHCP, DNS, etc., etc. Post more for a better answer.


You may benefit from perusing the "Planning Domain Controller Capacity" section over at the TechNet library. You will find that, as Jon Rhoades mentioned, 100 users is virtually a non-issue for any server and network device manufactured in the last 5 years. Unless, of course, you have some special uses that should be taken into account. Could you give us more info on what the environment is like? And need for a certificate authority? Lots of files being transferred on the network?

It bears repeating that you should focus less on performance and more on redundancy when specing out a server to be used as a domain controller. It will likely be the linchpin for your network and thus you should protect it like gold. Ideas include:

  • RAID 1 OS drives, with a hot spare
  • Failover network card (note: don't dual-home a domain controller)
  • A seconday DC, as Jon Rhoades mentioned, is a must IMO.
  • Reliable backup software that is made to take proper backups of a Domain Controller. Don't feel secure until you're successfully restored a few of the backups in a test environment.
  • Don't install anything extraneous on it. If you must, install it to a directory that is not on the system drive. Have a D: drive that is on a separate physical set of disks and not just a separate partition on the OS disks.
  • As Jon Rhoades mentioned, get good antivirus for it. However, I'd like to specifically add that not all AV products work on Domain Controllers. Get a product that is specifically advertised to be compatible with a Domain Controller and also manually verify that it is excluding the recommended directories and files. Yes, it's tedious. Not all of our tasks can be as glamorous as grinding out breathtaking regex.
  • Physically secure it and make sure it stays clean. I've seen servers that had enough lint, dirt and hair stuck in the grills to knit a sweater with. FWIW, carpet in a server room is a bad idea, but I digress. =)
  • Tripwire scripts to wipe the storage of any machine that scans or otherwise access the DC in a way that is unacceptable.
  • A trained bear to maul anyone who gets near the DC and doesn't give the secret handshake.

You get the idea. =)

  • 2
    Don't forget that you'll need to do periodic Bear maintenance to ensure the training isn't forgotten. I combine this task with our annual auditors' inspection of the DC.
    – AndyN
    Commented Feb 28, 2011 at 19:26

Like any database, the DC will benefit from being able to load the entire ntds.dit file into memory (rather than having to access the copy on disk all the time) so size the RAM appropriately.

That said, for 100 users, I don't think you're going to need that much (unless you have 1000s/millions on non-user objects taking up all the space).

A server with a recent dual-core CPU and 1-2GB RAM should do you fine. As your requirements grow, modify the hardware appropriately.

And, of course, get two and take backups... :)


You can get by with a dual core, dual NIC server with about 1024 MB of RAM. Windows 2003 has DC available OOTB; just add the Active Directory services role.

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