How to tap into network debugging

The author discovered a fascinating correlation between a network outage and an unexpected plumbing issue in their home. Despite having six Wi-Fi access points and Ethernet connections in a relatively small house, the issue persisted. The TP-Link routers, which were connected via Ethernet to a Netgear Nighthawk router, were unable to reach the internet, despite showing orange internet connection lights.

The frustrating part was that the author could still access the internet from their iPhone and Mac, which were connected via both Ethernet and Wi-Fi.

The author experimented with various troubleshooting methods, such as using the Tether app or TP-Link website to access the router remotely, but faced difficulties due to the router's irritating administration approach. Upon further investigation, the author realized that the issue was not related to the routers being compromised, but rather, it stemmed from an obscure setting involving DNS (Domain Name System) and Network Time Protocol (NTP).

The NTP settings, which control the time synchronization of devices on the network, were out of date. By updating the NTP settings, the author was able to retrieve the current time, which resolved the issue. Additionally, the author discovered that the issue was related to the router using its own IP address as the DNS server in most DHCP configurations.

While using public DNS servers like Google, Quad9, or Cloudflare can improve lookup speeds, in this particular case, it caused issues with content delivery networks (CDNs) and resulted in slower data transfers for large files and streaming. The author's solution was to revert the router back to using the ISP's primary and secondary DNS addresses, which resolved the problem.