I purchased a 1 Gbps down/up connection and noticed that I was consistently getting 95 Mbit/s down/up, regardless of hardware configuration (router, no router, switch, no switch, connecting directly to the ONT, cat 6/6a cables, etc) and regardless of software configuration (VPN on/off, firewall on/off, OS Linux/Android, driver updates, etc).
When nothing seemed to help on my end, I finally called my ISP. They could confirm that my ONT is a decade old and that they can see that each port only allows for 100 Mbit/s down/up.
I went through these steps before finally testing a direct connection to the ONT which finally made me call the ISP.
The ISP is going to replace the ONT for free.
Yeah, once my isp had me verify that the power light on my ont was on, then asked me to plug in a lamp to confirm the outlet was working…
Another time they had me do all kinds of troubleshooting, insisting there was no outage in the area… It turned out a truck had taken out the wires over the road.
On a related note to the last one, if we have a power outage, I get an email from them right away - before the ceiling fans stop spinning - warning me the internet might not work without power. But, somehow, they can’t detect outages in their own network.