Management of Static IP Addresses in the data center

The university where I work uses DHCP for the vast majority of our IP addressing needs. Workstations and the like.

However for servers we obviously use static IP addresses. The current method to figure out if an IP address is available works like this.

1. Guess an IP in the data center range, or look for one that doesn't show on the spreadsheet created nightly from the managed switch
2. ping it if it responds go back to step 1 if not procede to step 3
3. nslookup on it and see if anyone else has named it

About 90% of the time this works fine, but it is labor intensive, and not perfect. Given 10 administrators and about 300 servers in the main data center, and another 50 or so servers in our secondary data center, it seems like there should be a solution.

For static IP addresses (printers, MFDs, the occasional workstation) in the workstation ranges Client Services uses ipplan. It seems to be missing a few things we'd like: logging of who claimed IPs; multiple logins, preferably with LDAP so we can use existing accounts; a user interface simple enough that when you have to use it only a half dozen times a year it is still easy.

How do you manage your Data Center IP addressing? Do you track it? Is there "the IP address guy"? A paper list on the wall? Some variant on what we're doing with the poke til you find one?

We use a copy of dokuwiki, with a page for each used subnet. Whenever anything is commissioned, it's updated, althought we're small enough that if it's not updated for something, we can probably work out who did it.

I use the DHCP configuration file (ISC dhcpd.conf or the Microsoft DHCP server database) as "the spreadsheet". Spreadsheets fall out of data and are notoriously inaccurate in networks of any size. I allow new devices to pull addresses and then fix them down with reservations later. If I were working in networks large enough to need dedicated "DHCP guys" I'd still follow the same strategy. I'd push out automated exports (probably web-based) of the configuration in such cases so that the groups who don't administer DHCP can still see what the configurations look like.

All statically assigned devices (of which I try and keep as few as possible) are depicted as reservations (with a note indicating that they're really static assignments). All devices that can obtain DHCP do, and those devices that need to "appear" as static addresses are reserved.

I take the opposite stance as Kevin Kuphal-- I use DHCP reservations for nearly everything possible (I've had to renumber too many networks too many times). DHCP is an important infrastructure service-- as important as DNS or even basic IP routing-- and I use it extensively and make sure that I have a failover plan in place in case I lose my DHCP server.