Question: I was recently graced with a new job opportunity in a large higher ed NE department. This is my first job working with a large network of several thousand users.  

Throughout my education, I followed the idea that **static IP's are useful from time to time in certain applications and historically used more in smaller networks**. To this point, it has been my belief up to this point that **DHCP is much more useful in larger settings**. For this reason, I was shocked to learn that **each of our near 3000 networking devices have painstakingly been allocated static management IP addresses**. It was explained that this was easier to handle that DHCP.  

I will admit, the scheme for the addressing is nifty. The **second octet is the device-class/network identifier**, the **third octet is the building identifier** (we have some odd 200 buildings on campus), and the **fourth is the device identifier**.  

So the scheme is understandable, but still seems like a lot of numbers to remember; imagine I am looking for a Xirrus array in say the Cafeteria on St. Phillip's Street. Yes DNS could solve this, but the IP's do sometimes get changed and that could result in a nightmare if one is changed and not the other. 

The solution to me seems a DHCP/DNS combo.

So to sum up the question, **from a management standpoint, why is it a good idea to use Static or DHCP addressing on equipment?**

Answer: 
I’ll keep this post about your situation specifically.

First and foremost, managing over 3,000 devices with static IP addresses is just plain foolish. DHCP is a well-known and established protocol that solves the tedious task of manually assigning and fixing manual IP addresses. If they are that concerned about making sure they have control over **every** IP address on their network, set them as DHCP reservations. Even from a security standpoint, you don’t stand to benefit *that* much from eliminating DHCP servers. 

By sticking with this route, you will lose:

* **Change management capabilities**
* Customer insight

The big hitter on this list is change management capabilities. If you need to swap IPs around, you really don’t have a good way to do this; and that makes (or will make) your life arduous. If your teammates aren't on board with it and want to stick with their old ways, try to rope in your management and inform them of what a colossal waste of time it is. 

Regarding your nifty IP scheme; you will still be able to maintain that; If anything, to a greater degree. [IPAM](https://networkengineering.stackexchange.com/questions/7250/what-is-ip-address-management-why-its-needed-how-does-the-vendors-like-bluec/7253#7253) gives you the capability to drill down into smaller and smaller subnet ranges, making it seemingly easy to implement in your case. This will allow you to cascade further and further down into the building/device class you desire.
The answer to your question is mostly opinion, which is frowned upon on this forum. But I'm willing to bet real money that the majority of people here will agree with me.

I suppose that for some people, spending lots of time with Excel spreadsheets, keeping track of multiple spreadsheet versions, and the intellectual challenge of troubleshooting duplicate address problems are all enjoyable, but that's really no way to manage a network. I won't speculate on why DHCP was never implemented (*cough* fear \*cough), but DHCP will help you manage your network more effectively by freeing you up from doing a lot of mundane tasks that can and should be automated.

I should point out that not everything will use DHCP. Your routers, switches, firewalls, some servers, will need static addresses. But the majority of devices, especially end user PCs, wireless devices, printers, etc. should use DHCP.

What you really need is an IP address management application, or IPAM. There are commercial products as well as freeware that manage both DHCP scopes and static addresses.

You don't have to give up your nifty addressing scheme either. You can create DHCP "scopes" for each of your locations and device types. 

Certain devices that need stable addresses (like printers) can use DHCP reservations, so you can manage their addresses from a single application. That saves a lot of "running around" time.

In addition, you can use dynamic DNS, that syncs DHCP and DNS so that when an address is leased, a DNS entry is automatically created. Your Xirrus AP will always have the same name no matter where it is.