The Weirdest Network Issue I've Had to TroubleshootThe Weirdest Network Issue I've Had to Troubleshoot

There's a special kind of frustration that comes with a network problem you can't reproduce. These are the issues that happen only when you're not looking.

Over the years, I've seen my fair share of glitches, outages and misconfigurations. But there's always that one issue that sticks with you because it's so strange and so unexpected, it almost feels like a prank. It's the kind of problem that doesn't show up in a textbook or a cert exam, and no amount of best practices could have prepared you for it.

A True Story

It started with a ticket from a small branch office: "Users getting kicked off the VPN randomly." This wasn't too concerning at first, as we've all seen our fair share of flaky Wi-Fi concerns or misconfigured DHCP leases. But then it got stranger. It wasn't just the VPN. Teams calls would freeze mid-meeting, files wouldn't save to the shared drive, and sometimes the whole office would just quietly drop off the network for a minute or two -- and then come back like nothing happened.

We checked everything. The WAN circuit looked clean. Latency and jitter? Minimal. Packet loss? Zero. The switches were healthy. The firewall logs didn't show anything weird. The site had a Meraki setup, so I could even check heatmaps, event logs and client histories, and I still found nothing.

Related:The Status of Optical Transport Equipment

One day of issues might be a fluke. But this kept happening. Not every day, but often enough that people started asking, "Is our internet haunted?" Eventually, I did what every engineer dreads: I booked a site visit.

As soon as I walked into the server room, I knew something was off. First, it was hot -- uncomfortably hot. Not full data center meltdown levels, but definitely warmer than it should've been. I checked the room's AC, and it was working, sort of.

Then I turned to look at the network gear, and I saw it. There, plugged into the same UPS as the core switch and firewall, was a mini fridge. Yes, a mini fridge. Apparently, someone in the office had decided the server room was a good place to keep their Red Bulls cold. Every time the fridge's compressor kicked on, it drew just enough surge power to momentarily starve the other gear on the circuit. It wasn't enough to reboot anything, but enough to cause micro-brownouts that would drop connections or stall data flows, which was just enough chaos to cause "ghost" issues.

It made sense in hindsight. The problem was sporadic because the fridge wasn't always cycling. That explained why our logs never showed clean failures and why the issue was so hard to pin down. The hardware never actually lost power, it just dipped into an unstable state for a few seconds. Needless to say, the fridge was evicted. We got a vendor to run a clean power line for the rack, and just like that, the "ghost issues" vanished.

Related:How AI, Energy Requirements Are Shaping Data Center Investment

To this day, when someone complains about a network that "acts weird," I always ask myself: What else is sharing that power source? Because sometimes, your biggest network enemy isn't a misconfigured router, it's someone trying to keep their lunch cold next to your firewall.