On My Terminal Server

Mon, December 24, 2007 - 6:11 PM PST

I spent almost 48 hours trying to get access to my serial console server. Shortly after I got it, I reset it to factory defaults and used it for a few things, but otherwise it had been turned off for a few years now. But - after the recent work I did on my rackmount server - I decided that I didn't want to have to drag a monitor and keyboard to the rack every time I needed a console on that box and that since I have a console server, I had might as well use one. Thus began the disaster...

So, I decided that I'd set up the serial console first. This is usually really easy in Debian; just uncomment the appropriate line from /etc/inittab, change the speed to something faster than 9600, and tell init to read its config file again with `init q`. Then I went looking for a serial cable. I could only find one (I must have donated the rest), attached it to a null modem adapter and plugged it in. Nothing. That's when I took a closer look and saw that it was a cable from a UPS - and I had a nagging memory that APC used a different pinout.

More words I never imagined I'd ever say: I need a serial cable.

That's when I decided that I was under no circumstances going to purchase one of those. I've probably got 10 of them in my cube at work. And certainly not when I didn't even intend to use it long-term as I did want to use the terminal server. So I figured that init was configured correctly and the serial port worked so I might as well skip that step and assume it worked... and move onto the console server.

Everything went wrong here. My network had been renumbered since it had been used, so only the low /28 of the /29 I use could talk to it, then I couldn't remember the password. And when I went to factory default it, I realized that I didn't have a cable to get local connectivity to it once I hosed the network. Three trips to Radio Shack later (and the purchase of a digital multimeter, a breadboard, and several RS232 components), and many hours of swearing, I had a working RJ45-DB9 cable. That's when I found out that I didn't know the administrative password and the factory default instructions weren't working. So I was screwed at this point.

I probably tried 100 passwords. That's when inspiration struck me: serial. That didn't work, so I started subbing in numbers and symbols for characters and a few tries later, I guessed it correctly: s3ri4l. Once logged in, I set the admin password to be blank - said a few more cusswords - and configured the serial port.

It works. I probably won't have to use it for a year. And by then I'll forget how it works. And that'll probably be another post...