Thunderbolt/Ethernet works but diagnostic failed, why?

[enonod]

Macbook Pro early 2015 Retina. El Capitan; Thunderbolt to Ethernet adapter. TP-LINK 1200

Network/Thunderbolt Ethernet says it is connected. Wifi is off. Using TP-Link 1200b/s.
When I run network diagnostics it says the Ethernet failed and Network Settings failed for location Automatic.
ISP, Internet and Server show green.
The network seems to be working, I can see items on the network, use them and reach the internet.
Does this mean I am not at full speed, or that the diagnostics don't recognise this method or something else?

Any advice please.

 

[Cory Cooper]

Hello,

-What is the exact model of the TP-LINK device?
-Did you mean Wireless Diagnostics?

C

 

[enonod]

Thank you for responding Cory.
TP-Link AV1200 3-Port Gigabit. i.e. 1200Mb/s and no I do not mean Wireless. I am using a Thunderbolt 2 to Ethernet adapter. All works perfectly. The Mac built in diagnostic shows Thunderbolt Ethernet is connected using IPv4 DCHP, all is well.
'Help Me' Network Diagnostic shows Ethernet... failed; Network Settings... failed; ISP, Internet & Server show green.
WiFi is off. When selecting Ethernet as the choice for Network Port configuration the message...
in short... "There are other network port configurations that amy already be connected to the Internet.
If you want to use Ethernet check the box and continue."
Doing so gives the message...
"This computer does not seem to be connected to a DSL or cable modem, or to an Ethernet network. Make sure cable is connected etc. etc.".
Continue says that Network Diagnostics cannot fix the current networking problems. etc.
That is everything, I hope it gives a clue.

 

[Cory Cooper]

Ahhh...OK. hanks for the additional information.

It is probably due to a combination of the TP-LINK and Thunderbolt-to-Ethernet adapter. I believe it is reporting that because the built-in Ethernet is not connected, and that is what it is testing. It will show that Ethernet failed, as your MBP doesn't have a built-in Ethernet port, and requires the use of the adapter.

In the Network Diagnostics app, have you tried to select Other instead of Ethernet?

C

 

[enonod]

Thank you for your reply Cory. I accept thar direct connection must be required. I did try Other but it simply says it only tests Ethernet and wireless.
Thanks for your reassurance that nothing is amiss.