July 2001 was still reeling from the dot-com bubble burst. At work, we were still figuring out how to keep our infrastructure running in this new reality. Our web server was acting up, and I found myself knee-deep in a debugging adventure.

You see, back then, Apache was everywhere. We had several servers running it to handle the traffic for various internal and external applications. One particular weekend, one of these servers decided to act up. It started spitting out 502 Bad Gateway errors at random intervals, causing our application to fail over to a backup server.

I sat down on my desk in the small ops room, trying to figure out what was going on. The server logs didn’t give me much insight—just the occasional “connect” followed by an empty request and then a 502 error. Nothing too helpful there.

After a few hours of staring at the logs, I decided it might be worth checking our firewall settings. We were using Netfilter (the predecessor to iptables) for packet filtering. Maybe something was going on there? I went through all the rules, double-checking each one against recent changes and old bugs. Still nothing.

I turned my attention back to Apache’s configuration files, looking for anything that could be causing this weird behavior. There were some custom modules loaded up, but none seemed out of place. I started incrementally disabling them, hoping for a magic fix, but the server was still acting up like an unruly toddler.

At one point, I even considered swapping the hard drive to see if it was a hardware issue. The thought alone made me cringe—changing drives on a live production server? That’s risky business! But desperate times called for desperate measures, so I did just that. After replacing the drive and restoring from backups (we had those, right?), nothing changed.

It wasn’t until I checked our DNS logs that I started to get some clues. The domain name system was showing spikes in query rates to our server’s IP address during the times of failure. Maybe something was trying to take us down with a Distributed Denial of Service (DDoS) attack? I ran iptables commands to block specific IPs and monitored the traffic closely.

After about 12 hours, things started to stabilize. The DDoS seemed to have stopped, or at least significantly slowed down. I still had no definitive answer as to what exactly caused those 502 errors, but with the server running stable now, I was satisfied for the moment.

Reflecting on this experience, I realized that while Apache and Linux were rock-solid in many ways, they required diligent monitoring and quick action when things went south. The tech landscape back then was fast-moving, and staying ahead of potential issues meant constant vigilance and flexibility.

I spent a lot of time debugging in those days, but it’s these types of experiences that really drive home the importance of having robust tools like Netfilter, DNS monitoring, and solid backup practices. It’s not always about fancy new tech; sometimes, it’s just about being prepared for the unexpected.

And so, as I typed up a report on this ordeal, I couldn’t help but chuckle at how much has changed in 20+ years of my career. The technologies have evolved, but the lessons learned back then still resonate today.