When I first got AT&T fiber, I was getting roughly 100 Mbps upload and download with my Archer C2300.
That was quite a few months ago, and I haven't checked the speed since then because I wasn't having any problems.
Recently, I was troubleshooting something with my VPN and I noticed that my upload speed was now only about 10 Mbps, although download was still in the 90s.
Since nothing has changed regarding my physical setup, I figured it was on AT&T's end so I called them and had them speed test the fiber modem itself. It was uploading at 100+ Mbps, so the problem must lie with the router.
I've poked around in the C2300 settings a bit but I'm not sure what I should be looking for. Could this be an IPv4 vs. IPv6 problem? Any ideas or suggestions would be appreciated. Thanks