Is My Internet Being Siphoned? A Frustrating Experience with CenturyLink

Has your internet speed taken a sudden nosedive, leaving you scratching your head? That’s exactly what happened to me recently, and I feel like I’m on the verge of a digital mystery. Let me share my experience and maybe you can help me make sense of it all.

I’ve been enjoying CenturyLink fiber internet at my home in the Pacific Northwest for the past nine months. Initially, I was consistently getting an impressive 950 Mbps, with upload speeds hovering around half that. However, out of nowhere, my download speeds plummeted to a mere 4 Mbps—quite a stark contrast. The fluctuations have been baffling: sometimes I test at 20 Mbps, other times I see 100 Mbps, and it occasionally dips to 1.5 Mbps. In the meantime, my upload speeds remain excellent, often reaching up to 900 Mbps.

I reached out to CenturyLink’s customer support, where a technician ran numerous diagnostic tests only to conclude that everything appeared to be functioning normally. They dispatched a technician to investigate further. This technician examined the newly installed line, replaced the modem, swapped out the Optical Network Terminal (ONT), and even utilized brand new Cat6 cables—all to no avail. This was all done while testing via an Ethernet connection, which, by the way, only exacerbated the problem when I switched back to Wi-Fi.

Throughout the process, the technician kept inquiring, “Are you sure you aren’t using a VPN?” Well, to be honest, my knowledge of VPNs is quite limited, and I certainly don’t believe I am using one. After he left, I found myself just as confused as before. My subsequent calls to tech support yielded similar results: everything is fine, and once again, they suggested a VPN may be the culprit.

To add to my worries, I’ve noticed that when I conduct a Google search in Chrome, I’m often prompted with a CAPTCHA stating there’s been suspicious activity associated with my connection. This raises an alarming question for me: Could someone else be accessing my connection? Is it possible that someone has set up a VPN on my network?

As someone who isn’t particularly tech-savvy, I’m unsure where to start troubleshooting. If anyone has experienced something similar or has insights into what might be happening, I would greatly appreciate your input.

Edit: I should mention that I’m using Macs.

Edit 2: