| HN Mirror

Story time!

I've had this exact experience, except that it wasn't a dream.

Back in 2010 I had a weird issue where my cable connection would sometimes completely block the connectoin right after the DHCP response (we had dynamic IPs back then). This would go on for a couple of hours, until the IP lease expired, then my connection would come back. Luckily, I was running an OpenBSD box as my router which allowed me to diagnose the problem. But it was also impossible to explain to the servicedesk employees.

One evening it happened again, and I called the servicedesk, totally prepared to do the 'yes I have turned it off and on again' dance. But to my surprise the employee that I got on the phone was very knowledgable and even said that it was very cool that I had an OpenBSD box as a router. He very quickly diagnosed that someone in my neighbourhood was 'hammering' the DHCP service by not releasing his lease (a common trick to keep your IP address somewhat static). This caused a double IP on the subnet, and the L2 switch to block traffic to my port.

He asked me "do you know how to spoof your MAC with an OpenBSD box?". Then I knew this guy was legit. He instructed me to replace the last 2 bytes of the MAC with AB:BA (named after the music group). They had a separate DHCP pool for MAC addresses in that range. If they ever saw an ABBA mac address on their network, they knew it was someone who had connectivity issues before.

The problem was immediately solved, and I had a rock-solid internet connection for years, with a static IP!

I ended up chatting about networking and OpenBSD a bit, before I (as humble as I could) told the guy I was a bit flabbergasted that someone as knowledgable as him was working on the servicedesk.

It turned out, he was the chief of network operations at the ISP (the biggest ISP in my country). He was just manning the phone while some of his colleagues from the servicedesk were having diner.

Sometimes miracles do happen.