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I am in charge of a 70-computer, 50-user network distributed across two buildings and linked by a point-to-point line. We run Windows Server 2008 and so far we've been using DHCP to dynamically assign IPs to desktops and laptops over wifi as well.

Although DHCP is cool because you don't need to keep track of each machine/address pair, we have found a few issues with it over time. Sometimes we need to know to IP address of a particular machine and we don't have access to the DHCP server find out. Sometimes a device or service relies on a fixed IP from a machine, assuming that it will never change. Of course, we can pin some addresses to certain machines, but then the system becomes a mess of exceptions and documentation.

Also, sometimes I think that the pain of manually assigning an IP address to each new machine that we incorporate to the network is not that big; the DHCP server also needs some maintenance after all.

In short: is DHCP always the best choice for a small-ish environment such as the one I described? Would moving to a statically-configured environment be a big mistake?

CesarGon
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5 Answers5

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DHCP is the only choice (IMHO) when you get over 5 or 6 machines ( and even then ... )

In your case I would also setup dDNS so that your hosts register in DNS when they get a DHCP lease, so if you know the host name you know the ip address.

As far as host needed a static IP address. The best way is to let them configure off DHCP, but in the DHCP configuration reserve the IP address for that machine's MAC address. This lets you not have to manually configure IPs but still have "static" ip addressing.

Zypher
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  • The answer to this question of mine might help with the dDNS aspect: http://serverfault.com/questions/106203/how-does-windows-2003-handle-creation-of-dns-records-from-dhcp – Kyle Brandt Jan 28 '10 at 19:36
  • Thanks Zypher and the rest. You have ratified that DHCP is always the best option for a mid-sized setup like ours. – CesarGon Jan 28 '10 at 19:41
  • We actually do have dDNS set up, and it works well. :-) – CesarGon Jan 28 '10 at 19:42
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    I would amend the answer to include this: "Clients get dynamic IP's, servers get either static IP's or DHCP 'reserved' IP's." If a system has to act as a server (even if it's just someone's workstation that's left on when they're not around) consider it a server. – George Erhard Feb 27 '13 at 23:40
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Fixed IP addresses for servers - always. Printers and the like can be done either way but my preference is for fixed. Workstations, laptops and the like should always be DHCP. You should be able to solve your problems by using dynamically updated DNS. Then you don't need an IP address because you can just use the machine name.

As l0c0b0x says, if you don't have access to the DHCP server you really need to fix that. An administrator should always have control over his/her network.

John Gardeniers
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If you're talking about servers you should not be using DHCP to configure their IP addresses. This creates all sorts of headaches long-term, and even Microsoft will tell you it's not a recommended practice.

I relate the parable of the DHCP network that got moved to CoLocation and left the DHCP server behind: Needless to say nothing worked at the CoLo and the admin in question looked looked like an idiot.

For Desktops and Laptops by all means use DHCP, possibly in combination with static leases if you need to ensure that machines always have the same IP when they come onto your network. This is the most sensible configuration for your end users as it lets them put their laptops on other networks (home, hotel, starbucks) without jumping through a million hoops.

voretaq7
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Here's your main issue (as stated):

"We don't have access to the DHCP server"

Why don't you have access to your internal DHCP server? (fix this!)... Your number of clients concords with most environments using DHCP (recommended). Yes, static IPs would drive you nuts!

l0c0b0x
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    Sometimes we don't have access to our DHCP server because we're (literally) working inside a 3-metre deep trench in the middle of a field, with a patchy connection to our remote access server via satellite link and crappy bandwidth. We *do* have access to the DHCP server from inside the buildings, of course! :-) – CesarGon Jan 28 '10 at 19:39
  • @CesarGon: Sounds interesting. What kind of company do you work for? – joeqwerty Jan 28 '10 at 19:59
  • I'm with The Heritage Laboratory, a small research lab in Galicia, Spain. http://www.iegps.csic.es/lapa :-)) – CesarGon Jan 28 '10 at 21:10
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Maintaining a static addressed network quickly becomes a hassle with more than 10-15 machines. You can set static addresses within the DHCP server's GUI. While these are only faux static addresses they ensure that no other device can get that address by requesting it from the DHCP server and when that particular device asks for an address it will always receive the same one.

TrueDuality
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