netcurmudgeon (netcurmudgeon) wrote,

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I had the good fortune to already be planning to work from home today. That way, I was not required to pry myself out of bed extra early and clear four inches of soggy snow in the driving freezing rain. And, I experience no pangs of guilt that might have accompanied a weather-driven "I'm working from home today".

After days worth of procrastinating I finally put together the budget case document for the project we know the City Council will not fund. I packed it off to the Boss and washed my hands of it. Then, I set to doing something actually useful. Or, at least, useful to me.

We're rolling out wireless access points in all of the schools -- over 250 so far, with another ~500 to come. They're Cisco "LWAPs" -- lightweight wireless access points that get an address through DHCP and then register with a central controller. The controller then does all the heavy work of telling the APs what to do. It's a wonderful system for large-scale deployments: make a change once on the controller, and Shazam all the APs have it.

Insert long pause to give bottle to baby so ashacat can sleep. Baby takes bottle, soils several diapers, almost finishes bottle, poops more, projectile vomits (I'm sitting on the couch with him dripping regurgitated milk, thinking I've been hit! Medic! Medic! and laughing my head off) and has a meltdown on the changing table so loud that he rouses Asha from the other end of the house...

The thing is, you want all of the APs to have the same IP address all the time, so that you can track their up/down state more easilly. The way you do this is by setting up "reservations" in your DHCP server so that each specific AP gets the same IP every time it asks for an address.

I will give Microsoft points for this: with Windows 2003 server there are now a lot more things that you can do through a command-line interface. One of them is administering your DHCP server.
The Old Way would have involved hours of clicking and typing through the "Add Reservation" dialogs. The New Way, with the netsh utility involves pasting in one line per AP from a text file you can esilly cook up in Excel (with a quick massaging in TextPad):
#add res <ip> <mac> <resname> <note> <mode>
dhcp server scope
add res 000b858e9d50 CM-LAP-RM303 2007060121 DHCP
add res 000B858E98B0 CM-LAP-RM310 2007060122 DHCP
add res 000B858EA440 CM-LAP-RM307 2007060123 DHCP
add res 000B858f43f0 CM-LAP-RM360 2007060125 DHCP
add res 000B858EA3D0 CM-LAP-RM343 2007060124 DHCP

Creating reservations for over a hundred APs? With scripting it's the work of an hour. This is progress.

At the end of the day I had all of the reservations done, and had added al of the APs to our NMS system. Far more rewarding work than preparing a document you already know will go nowhere. ;-)
Tags: dhcp, geeking, wifi

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