I've had a very similar problem with my cable internet circa 2010. It must have been DOCSIS 3.0. Multiple times a day my connection would stop working completely. The modem's 'connected' and 'carrier up' and 'carrier down' lights were on, and I had LAN communication with the modem, but no data would pass though on the WAN side.
From the management page of the modem (I later learned you weren't supposed to know about) I could see the upstream and downstream carriers were correctly established and still operational, but on the IP (PPPoE) level the TX (upstream) packet counter was increasing, but the RX (downstream) packet counter did not. Releasing the IP on my router (remember, it was PPPoE), then waiting 10 minutes or so before renewing the IP via DHCP would bring connectivity back.
I would call to my ISP (the largest ISP in my country) to try to resolve the issue. Every. Single. Time. I had to explain to the support employee that yes, I did disconnect and reconnect power, yes, my computer's software was up to date, yes, I did try connecting via LAN directly to the modem to eliminate any possible router issues, etc.
Now, at this point in the story I should point out that I held a degree in electrical engineering, specialising in embedded systems and high-speed data transmission and also had just about all Cisco networking certifications. I was more than qualified to design cable modems myself, imagine the frustration wasn't able to fix this issue.
One night I came home to the same problem, called customer service again, fully prepared to do the 'dance' of answering every basic troubleshooting question. But to my surprise, the guy on the phone seemed legit knowledgable. When I described him the symptoms I saw from the modem's management page he was rather surprised that I managed to discover that functionality, but said he knew what the problem would be then.
The support employee was quickly to confirm that someone in my neighbourhood hard-coded his IP-address instead of allowing DHCP (a common trick back in the day to get a static IP on a residential cable connection), and that that IP was clashing with the IP their DHCP would assign to my router's MAC address. He asked me what brand of router I had, and had to explain to him that it was a self-built OpenBSD box. His response was: "great! then you probably know how to spoof the MAC on your WAN interface then?". I did, I changed my MAC to a value he gave me, and immediately my connection came back up. He explained me that any MAC address starting with AB:BA (named after the band) was reserved for a special block of customers with this kind of issue.
We continued chatting a bit about DOCSIS, networking technology, modulation types, OpenBSD (it was also his favourite OS) and much more nerdy stuff. At some point I asked him, respectfully, how someone with his knowledge ended up at the support helpdesk of an ISP. He then told me he was the ISP's CTO, in charge of all network operations, and that he was just manning the helpdesk while his colleagues were on a diner break...
Man, I remember when you told this story some years ago, and I still very much like it !
(I have an hnrss.org feed with all comments mentioning OpenBSD, so, I was bound to catch it).
I've had a very similar problem with my cable internet circa 2010. It must have been DOCSIS 3.0. Multiple times a day my connection would stop working completely. The modem's 'connected' and 'carrier up' and 'carrier down' lights were on, and I had LAN communication with the modem, but no data would pass though on the WAN side.
From the management page of the modem (I later learned you weren't supposed to know about) I could see the upstream and downstream carriers were correctly established and still operational, but on the IP (PPPoE) level the TX (upstream) packet counter was increasing, but the RX (downstream) packet counter did not. Releasing the IP on my router (remember, it was PPPoE), then waiting 10 minutes or so before renewing the IP via DHCP would bring connectivity back.
I would call to my ISP (the largest ISP in my country) to try to resolve the issue. Every. Single. Time. I had to explain to the support employee that yes, I did disconnect and reconnect power, yes, my computer's software was up to date, yes, I did try connecting via LAN directly to the modem to eliminate any possible router issues, etc.
Now, at this point in the story I should point out that I held a degree in electrical engineering, specialising in embedded systems and high-speed data transmission and also had just about all Cisco networking certifications. I was more than qualified to design cable modems myself, imagine the frustration wasn't able to fix this issue.
One night I came home to the same problem, called customer service again, fully prepared to do the 'dance' of answering every basic troubleshooting question. But to my surprise, the guy on the phone seemed legit knowledgable. When I described him the symptoms I saw from the modem's management page he was rather surprised that I managed to discover that functionality, but said he knew what the problem would be then.
The support employee was quickly to confirm that someone in my neighbourhood hard-coded his IP-address instead of allowing DHCP (a common trick back in the day to get a static IP on a residential cable connection), and that that IP was clashing with the IP their DHCP would assign to my router's MAC address. He asked me what brand of router I had, and had to explain to him that it was a self-built OpenBSD box. His response was: "great! then you probably know how to spoof the MAC on your WAN interface then?". I did, I changed my MAC to a value he gave me, and immediately my connection came back up. He explained me that any MAC address starting with AB:BA (named after the band) was reserved for a special block of customers with this kind of issue.
We continued chatting a bit about DOCSIS, networking technology, modulation types, OpenBSD (it was also his favourite OS) and much more nerdy stuff. At some point I asked him, respectfully, how someone with his knowledge ended up at the support helpdesk of an ISP. He then told me he was the ISP's CTO, in charge of all network operations, and that he was just manning the helpdesk while his colleagues were on a diner break...