I keep getting this error in DMESG.
> Downshift occured from negotiated sped 1Gpbs to actual speed 100Mbps, check cabling
Also the interface from the dashboard is configured at 1000Mb/s which is not true.
I have a 100mbit connection.
How can I fix this or reconfigure the interface media subtype?
Check the cabling
Two suggestions:
Check cabling / type, especially if it’s longer or runs adjacent to known interference sources like AC power lines. 1 gigabit tends to be pretty resistant but it can happen. Better cables (CAT6 and up) tend to be more resistant to interference in general.
Also, can try and turn off auto-negotiation and fix speeds to 1G. That has been a pretty persistent issue for some of my equipment and the Mikrotik switches I use. APs may downshift to fast ethernet on account of a cable switch, a random bit flip, or whatever. Thus, I turn off auto-neg on those connections.
The cabling is fine as demonstrated by download/upload speeds.
My interface has the wrong configuration and there is no option to change that from the GUI as far as I can see.
Your server and whatever is at the other end (I’m assuming router) will negotiate a speed. The error message is saying that the speed was originally negotiated at 1000mbps, but was ‘down-shifted’ to 100mbps. This can be caused by interference or bad cabling, among other things. This is why the error suggested checking the cabling.
Your internet speed is irrelevant. Whether you make use of the 1000mbps is something only you can answer, but you don’t need faster than 100mbps WAN to take advantage of 1000mbps to your LAN. I have 400mbps WAN and 10gbit LAN. I can’t copy data to the internet >400mbps, but I can transfer data around my home network at up to 10,000mbps.
Your options are to check the cabling as suggested (perhaps try a shorter or different cable), disable auto-negotiate as suggested, or ignore the error message.
Ok. Thank you for clarification. I misunderstand your first reply. I will check the cableing then and also the auto negotiate as you suggest.
Its probably simpler to just replace the cables between the NAS and the switch - just make sure you use decent ones, but most SHOULD be OK.
For 10/100Mb only 2 pairs (of 4) are used. 1000Mb use all 4 pairs this is why the obvious solution is a replacement cable as the issue is PROBABLY a broken wire in the cable somewhere (normally at one end)
Just a follow up. Just replaced the cable and link is up:
> Link is Up - 1Gbps/Full - flow control rx/tx
Tbh the cable was my last point of failure because it was pretty new still. Anyways, IT 101, replace cable and see if issue persists.
Thanks again to all for quick response and have a nice weekend 
