Ones and Zeroes

Tuesday – 22 March 2016
I’ve worked in IT, in some capacity or other, for almost 15 years. I enjoy it; I’m even nominally good at it. Today, however, I had to call my ability in this field into question.

A little over a month ago, I was tasked with spinning up a new server for an application that we’re going to vet and possibly put into service. And I did. And promptly went on my merry way with other tasks and projects. This morning, I had to come back to that server and do some additional configuration. I attempted to remotely access the machine. No go.

Huh.

Undaunted, I considered that I’d possibly built the machine in a different site. So, I tried to connect using that sites code. Still no go, Flight.

What the…?

At this point, I started getting “a little” concerned. I was sure that I’d built the machine, but not being able to connect to it or even ping it caused some alarm.

 

I logged into the local virtual machine cluster to look for the machine. There it was, big as day and twice as bright. It was on, so that negated the “Did I remember to turn the bloody thing on” question. I opened its vm console, logged onto the server, and validated that it was working properly. It was. I tried pinging the server from other machines. Pings out, no ping replies returned. I pinged the other machines from the server. Pings out, ping replies returned.

The last time this happened – last week, actually – I had neglected to turn off a server’s firewall, preventing it from responding to any external contact.

I looked at the firewall settings; it was turned off. Good. I checked its IP address. I was able to ping it from other machines. Okay, that narrowed down the range of possible problems, but it raised another question. The server properties showed that it was joined to the domain, so it should (operative word) have been registered properly in DNS. I prepared to remove the system from the domain and re-add it when I saw what the problem was.

I had mistyped the computer’s name when setting it. I hadn’t caught the error because I kept looking at the correctly-typed name in its VM console window.

...

I renamed the computer, removed it from and re-added it to the domain, and in probably the least-surprising thing I’ve encountered today: It appeared to pings and remote calls.

Super. Genius.