mac ethernet connection OK but no internet
Spent hours troubleshooting an internet access problem and thought I would post for others who might have a similar experience. I benefited greatly from many of the suggestions in this support community but none of those posts identified the problem.
I have a Mac Mini, mid 2011, running OS X 10.10.3. Connected via ethernet to an Airport Extreme router. One morning I could not connect to the internet. The odd thing is that Network Diagnostics indicated green dots for Ethernet, Network Settings, and ISP but the Internet and Server dots were orange/yellow. Followed many suggestions in this support community to restart the Airport Extreme, renew DHCP lease on the Mac Mini, etc. with no success. However, if I turned Wi-Fi on in Network Preferences the Mac Mini connected to the internet without a problem. In addition, other devices connected via ethernet in other rooms connected to the Internet normally. So, there did not seem to be a problem with the Mac Mini or the Airport Extreme. I suspected the problem was with the ethernet network configuration on the Mac Mini but had no success trying different configurations.
I have an ethernet switch in between my Mac Mini and the Airport Extreme. I tried a power cycle on the ethernet switch but still had the problem. Finally, I connected the ethernet cable from the Airport Extreme directly to the Mac Mini without going through the ethernet switch and everything was back to normal. But I need to use the ethernet switch for other devices in the room. So I re-connected the ethernet switch in between the Mac Mini and the Airport Extreme and everything now works normally. Unplugging the ethernet cable from the Airport Extreme to the ethernet switch seems to have reset a connection even when a power cycle of the switch alone did not work.
The odd thing about this experience is that Network Diagnostics could not determine the cause of the problem and Network Preferences showed "Ethernet is currently active and has the IP address 10.0.1.XX".