Years ago I worked as a developer for a company that also owned a small ISP. The sysadmin for the ISP had quit and they didn't bother to replace him, as another guy could usually keep things running. Until a huge wave of spam hit and the mail server went unresponsive. Typical for that time, the mail server was sendmail with an unholy, gnarly config including SpamAssassin with an unholy, gnarly config. The guy handling sysadmin duties was out of his depth. He gave me access, showed me around the configs, and asked me to help. Sure, I could help. But not in any kind of acceptable time frame. So I went back to my desk and thought about it a bit.

A while before I had installed OpenBSD on an old box to play with. I recalled seeing something about a transparent bridge setup, so I got the idea of putting a transparent bridge with greylisting in front of the mail server. So I grabbed a slow cast off desktop, slapped an extra NIC in it, got it configured so I thought it would work, and put it in place. A few tweaks later and the load was off the mail server and it began responding to legitimate requests and clearing out its queue.

From idea to working solution took about 4 hours, including scrounging up parts, installing, and everything. I'm sure something similar could have been done with another OS, but what level of expertise would it have required? I was pretty much an OpenBSD newbie then, doing things I'd never even played with before, and that stuff just worked.

Michael W. Lucas has written many technical books, all useful and all with the same wry humor. His earlier books were published by No Starch Press. He has self-published more recent works at Tilted Windmill Press.

I found this while Googling for unrelated OpenBSD stuff:

http://www.skeptech.org/blog/2013/01/13/unscrewed-a-story-ab...