Any network gurus out there? I'm baffled...

[rexone]

One of our iMacs on our home network is consistently having problems with internet connection.
It will just randomly drop-out.
I have had it connected by ethernet but it will not connect to the internet at all that way (it can use the LAN no problems), sometimes it will show 'green' in the network control panel but still not connect to the internet. Most of the time it just shows orange.
Every other device connected to the same switcher (AppleTV, Playstation, Cable TV, TV) have no internet problems.
So it's connected wirelessly and is still having problems.
Signal is strong so that's not the issue.
All other devices that use same wifi network (iPad, 3 x iPhones) have no network stability or connection issues.
Understanding & fiddling with IP addresses etc is totally out of my realm of expertise so any help would be greatly appreciated.

 

[jahala]

One of our iMacs on our home network is consistently having problems with internet connection.
It will just randomly drop-out.
I have had it connected by ethernet but it will not connect to the internet at all that way (it can use the LAN no problems), sometimes it will show 'green' in the network control panel but still not connect to the internet. Most of the time it just shows orange.
Every other device connected to the same switcher (AppleTV, Playstation, Cable TV, TV) have no internet problems.
So it's connected wirelessly and is still having problems.
Signal is strong so that's not the issue.
All other devices that use same wifi network (iPad, 3 x iPhones) have no network stability or connection issues.
Understanding & fiddling with IP addresses etc is totally out of my realm of expertise so any help would be greatly appreciated.

I think this is the best place to start is to configure your iMac like your iPad, 3 iPhones, and your other devices since they work fine. Open System Preferences and click on Network. Click on the active interface, e.g. Ethernet or Wi-Fi, and then click on the Advanced button in the bottom, right corner. Look at the TCP/IP tab of the advanced settings. Most of the time, you will want Configure IPv4 to be Using DHCP and Configure IPv6 to be using Automatically. If either of those is different, change it.

Then click on Renew DHCP lease to make sure your settings are updated. Click OK in the Advanced Settings and apply in the System Preferences.

If you still have problems, go back in the advanced settings of the network interface and click on the DNS tab. Remove any manually added IP addresses in the DNS Servers: list. You may want to save the information for later just in case you need to add them again later. Then click OK and then Apply.

Good luck. I hope it works out.

 

[Altemose]

@rexone Open --> System Preferences --> Network and select your Ethernet connection on the left side. Hit the minus icon and delete the service. Then hit the plus button and select "Ethernet" and let it reconfigure the Ethernet with the stock settings. Also, make sure that the location is set to "Automatic".

 

[winston1236]

By internet you're meaning WiFi I think? If so, how far is it from the WiFi box?

 

[mmomega]

if the DNS got messed up at all on the computer that can cause all sorts of issues like intermittent internet and much more. Or a static IP and the Mac gets turned off and another device takes the IP address that the mac is wanting.

 

[caskibum]

Is the wifi connection intermittent? i.e. it works sometimes and not other times? If so then you don't have a config problem, you have a different issue.

For the ethernet (cabled) connection, disable your wifi (in network settings), connect the cable and open a terminal window.
Post the results of:
ifconfig
netstat -r
dig google.com
(redact any personal info before posting).

Might help in determining if you have a configuration issue.

 

[satcomer]

Try the steps in the blog post Fix Wi-Fi Problems in Mac OS X El Capitan and see if it helps.

 

[hobowankenobi]

@rexone Open --> System Preferences --> Network and select your Ethernet connection on the left side. Hit the minus icon and delete the service. Then hit the plus button and select "Ethernet" and let it reconfigure the Ethernet with the stock settings. Also, make sure that the location is set to "Automatic".

If this doesn't solve it, check and see what DNS IP address is being used. Some ISPs DNS can be flaky.