At my day job, we were tasked with creating a Windows NT 4.0 network from scratch with only minimal training on operating system. We were experts at working with OpenVMS and MacIntosh systems, but none of us had ever seen Windows NT before. In those days long ago we were very cocky, and very naive - how hard could it be to set up a new TCP/IP network? After all, we had mastered DECnet and Appletalk, could IP be any harder?
We soon learned error of our ways - TCP/IP is far more complex than we had originally believed. However, after some head scratching and a few phone calls, we managed to get our network up and running.
We didn't know any better, so we simply hard coded TCP/IP address into each workstation and server. In fact, we hard coded everything, including DNS and WINS server addresses, subnet and gateway address.
For our purposes, this worked great for several years. We added machines slowly and planned everything far in advance, so it was no big deal to just add a new machine to network. A few simple edits to network control panel was all that was needed, and since our network was very static, we didn't have to visit those setting very often at all.
As our company grew this scheme started to get more and more awkward. Originally we had a nice, isolated, self-contained network, but now we needed to get on internet, we were adding not only new workstations and servers at a furious rate, but we had to deal with PDAs, handheld systems, standalone file servers and hundreds of other computers.
To make matters even worse, where our network was very static, now it was becoming dynamic. Computers would be added and removed constantly - someone would plug his handheld into an ethernet jack, get their email, unplug and be gone.
The static TCP/IP scheme that we had been using (a spreadsheet with a list of machines and related addresses) was simply no longer working. Fortunately, there was an answer - DHCP.
The acronym DHCP stands for "Dynamic Host Configuration Protocol", and it means exactly what it says. Once we discovered this new tool we realized we had found solution to our problem - and we kicked ourselves mentally for not reading up on this wonderful tool long before.