So I just setup OPNSense today, I noticed that whenever I reboot my OPNSense machine my LAN interface defaults to 100baseT, when I have a Gigabit unmanaged switch hooked up to it via a cat6a patch cable.
If I switch it from "Default" to "1000baseT" it breaks the connection, but if I switch it back to "Default" after switching it to "1000baseT" it fixes itself. This only happens when my OPNSense machine boots. Any ideas what's causing this and how to fix it?
These issues are usually hardware related. Swap out components until it is fixed.
In my experience, it is often the cable.
Bart...
Agreed. Most likely the cable has a broken wire and it's only using half the pairs which is 100M.