iMac27 Dropping Ethernet Connection

[skays]

Well...it happened again. Even after switching ports on my Netgear AP device. After over 3 days of working fine, tried to log into my iMac to find no connection to internet.
- Checked the status of my Netgear AP device and port #2 status light was green, so the AP device is working and sending signal to my iMac.
- Went to System Preferences>Network to see "Ethernet 2 (status orange) Self-Assined IP. Status: Connected - Ethernet 2 has a self-assigned IP address and will not be able to connect to the internet."
- Shut down the iMac and turned back on...everything back to normal.

FYI...I "do not" put my computer to sleep and Screen Saver comes on after 1 hour.

I am at a loss. My concern is if this is a sign of something worse to come? Purchased my iMac directly from Apple in January 2018, so a little over 3 years old. My Apple Care ended 29 January 2021. But I purchased my iMac using my American Express Card and I believe using my Amex extends the warranty by 1 year?? Anyone know anything about that?

Any and all help greatly appreciated.

 

[MacInWin]

I am beginning to suspect the Netgear AP more than your iMac. You now have two ports on it that don't work to provide DHCP IP addresses. How old is the Netgear?

 

[skays]

Both ports of the Netgear AP...2 and 3...have always shown green.
What is confusing to me is what is displayed within System Preferences>Network:
- Ethernet 2 (ethernet connection to the AP), displays an "Orange" dot and "Self-Assigned IP" How does an 'orange' dot differ from a 'red' dot?
- Status: "Connected. Ethernet 2 has a self-assigned IP address and will not be able to connect to the internet"

If my system "...will not be able to connect to the internet...", wouldn't there be a "Red" dot next to Ethernet 2 and rather than "Orange"? And would not the 'Status' show "Not Connected" rather than "Connected"?

Also spoke with American Express. They will provide warranty support for 1 year beyond the 3-year Apple warranty I purchased. ??

I also found out there is a new store in my area (Florida Pan Handle)...Simply Mac...that provides authorized Apple service and support. Spoke with them and they said to bring my computer down and they will run diagnostics. A lot better than driving over 3 to 4 hours to an Apple store in Birmingham, AL.

And one person suggested that if all else fails and my Netgear Access Point system is working, just unplug the ethernet cable from my iMac and connect to the AP system via Wifi. Very frustrating.

 

[lclev]

You never said if you tried what I suggested in a previous post. Have you tried to manually configure your network settings? If not try the following:

Under System Preferences -> Network -> Select Ethernet connection -> Advanced -> TCP/IP ->change under configure IPv4 from Using DHCP to manual and input the following:

IP address: 192.168.1. 50.
Subnet Mask: 255.255.255.0
Router: 192.168.1.1

Leave IPv6 as Automatically

Click okay. If you get an IP address conflict - and it would be good to check on your router to see if the above IP address is already in use - just change the last number - 50 - to something else.

If that works then it is not the iMac.

Lisa

 

[MacInWin]

Both ports of the Netgear AP...2 and 3...have always shown green.
What is confusing to me is what is displayed within System Preferences>Network:
- Ethernet 2 (ethernet connection to the AP), displays an "Orange" dot and "Self-Assigned IP" How does an 'orange' dot differ from a 'red' dot?
- Status: "Connected. Ethernet 2 has a self-assigned IP address and will not be able to connect to the internet"

If my system "...will not be able to connect to the internet...", wouldn't there be a "Red" dot next to Ethernet 2 and rather than "Orange"? And would not the 'Status' show "Not Connected" rather than "Connected"?

Also spoke with American Express. They will provide warranty support for 1 year beyond the 3-year Apple warranty I purchased. ??

I also found out there is a new store in my area (Florida Pan Handle)...Simply Mac...that provides authorized Apple service and support. Spoke with them and they said to bring my computer down and they will run diagnostics. A lot better than driving over 3 to 4 hours to an Apple store in Birmingham, AL.

And one person suggested that if all else fails and my Netgear Access Point system is working, just unplug the ethernet cable from my iMac and connect to the AP system via Wifi. Very frustrating.

The status of Orange says that the Mac is connected to your LAN ok, that it is communicating ok with the network, but that the server that it thinks issues IP numbers (supposedly the one in the Netgear device) did not assign an IP to the Mac when it asked for one, so it self-assigned a number to communicate on the LAN. However, because the Netgear doesn't know about that self-assigned number, it won't pass the traffic from the Mac to the Internet. It will only handle traffic on the LAN from IP numbers it assigns. So the Mac says, "I'm working fine, but I'm not getting a number from the router." The green light on the router says it "thinks" it is working, but because it is not assigning an IP, it is clearly not really working. A Red light says that the port is not working at all.

So, from your reports of an orange dot, that tells me the router is not working, but the Mac is. What happens if you click on the "Renew DHCP Lease" button in System Preferences/Network/<<interface>>/Advanced? Do your setting look like mine in Post #14? Can you screenshot and post your settings on both the basic and advanced pages for us to see?

 

[skays]

Should I wait until I have another internet problem before clicking on the "Renew DHCP Lease" option?
Attached are screen shots of both the basic and advanced pages of System Preferences/Network. Internet is working fine. The third screen shot is of the basic page when internet not working this morning.

 

[skays]

As an aside, can anyone recommend reliable computer diagnostic software that would identify existing or possible future issues on my iMac? I am wary of using third-party software. I have run Applie's Disk Utility and no issues have popped up. Computer bogs down often like it has insufficient memory. I am running a 3.8 GHz Quad-Core Intel Core i5 processor with 16 GB 2400 MHz DDR4 installed. Also have a Radeon Pro 580 8 GB Graphics card as well. My wife likes to do jig saw puzzles a lot and often programs starting running slow or irratic. Restarting/rebooting fixes the problem. Hints or ideas appreciated.

 

[MacInWin]

For the diagnostics, just open Activity Monitor and look at the Memory page for memory usage. As long as Memory Pressure is Green, it's not memory bogging down the machine. Also check the CPU tab to see what is taking all the CPU when it is bogged down. You can sort the columns in the display by clicking on the header. You can click to put the heavy hitters first, or heavy hitters last.

I'm assuming the jig saw puzzles are heavy on graphics, which could be slowing things down, but without more information it's just a guess.

Looking at the screenshots (Thanks, by the way, they do help), I would suggest that you change the DNS server on the Ethernet/Advanced/DNS tab to add some in addition to the default router. Just click on the "+" at the bottom of the window where the DNS number are and add 1.1.1.1, 8.8.8.8, and 8.8.4.4 to the list. Those are all good DNS servers that will work for you better than the default you are showing.

Also, I see the location block is "home" where normally it's "Automatic." There are reasons to have a different location, but I would give "Automatic" a trial, it may work better for you.

EDIT: I see in post #8 that Lisa suggested a change from Automatic to something else but you never said you tried it, so I would go back to Automatic if you did and it hasn't made any difference. Automatic is generally better than an assigned location.

 

[lclev]

Jake - it was suggested he create a new connection and call it "home" but all the settings should still be automatic. The reason was to see if the automatic setting was corrupt.

I suggested setting manual settings only to see if the Netgear or router is the issue. If the iMac has an ip address manually assigned and it stays connected - it most likely is either the AP or what ever is handling DHCP. If the issue persist then the iMac modem has issues. I use this at work to troubleshoot. I also do a deep dive and remove plist files to force a reset of the adapter but I don't think that procedure would be prudent at this time.

Interesting to note - WiFi is turned off. Why? Is there an issue with it too?

Lisa

 

[MacInWin]

Lisa, I know that it was suggested. But he never reported back that he had tried it, that I could find. I still think it's the router not assigning an IP through DHCP. Good question about the WiFi, but it may be that he wants the higher speeds available through Ethernet. I have both turned on on my MBP because I want the speed but also want to use my Apple Watch to unlock and that unlocking takes both WiFi and BT to perform.

The next thing I would suggest is setting the DHCP server on the "home" location, if that is what he will use, to the router directly, 192.168.0.1, and see if that works. It could be that there are conflicting addresses in the network somehow that might be contributing. I don't think it's the Mac, although it can't be ruled out. Just ver unlikely.

 

[skays]

Got up this morning and no internet. As I am not that techy, I have not done what IcIev suggested and followed MacinWin's suggestions.
- Went into System Preferences/Network/basic and changed the Location from 'Home' to 'Automatic'.
- Went into System Preferences/Network/Advanced>DNS Tab and added the three 1.1.1.1, 8.8.8.8, and 8.8.4.4 DNS servers.
I restarted my iMac and it connected to the internet. Looking at the System Preferences/Network/Basic page it connected in the 'WiFi' mode. I attached two screen shots: System Preferences/Network/basic, and System Preferences/Network/Advanced>DNS Tab. It is interesting to see that:
- Now only Wi-Fi and Ethernet now show in the System Preferences/Network/Basic page and my iMac defaulted to Wi-Fi. It also works/connects when Ethernet is selected. Does it connect to one or the other based upon the best/strongest signal source or is Wi-Fi the default?
- The DNS server numbers I manually entered (1.1.1.1, 8.8.8.8, and 8.8.4.4), are no longer there and have been replaced with 68.105.28.12, 68.105.29.12, and 68.105.28.11. I don't understand what that means.

I assume I should just use whatever source (Ethernet or Wi-Fi) the iMac connects to? And the Wi-Fi signal icon on my top screen menu bar shows 3 'fan' bars as well.

You all have been a wealth of help. I plan on taking my computer to a new Mac service store in my area...20 miles away...and have them run diagnostics. Should they be able to tell if there is an issue with the iMac modem?

 

[MacInWin]

Actually, your screenshot shows you connected by BOTH Wifi and Ethernet. Both have green dots. And the DNS setting you showed in the screen capture are most likely from your Internet Service Provider (ISP), the service that the router is attaching to externally. I wonder if you entered the new DNS servers in just WiFi and not in Ethernet? There is a separate place to set DNS for each interface.

There is a way to set priorities for which to use, WiFi or Ethernet. Click on the little icon to the right of the "-" button at the bottom of the list of interfaces and a menu will drop down. Click "Set Service Order" and a new window will open with the two interfaces showing, As it says, drag them into the order you want and then click OK. It's easier to click on the WiFi and drag it down below Ethernet in your case. When you get back from the screen, click on Apply to make the changes permanent.

 

[skays]

I checked the DNS server settings in both Wi-Fi and Ethernet, and the DNS service addresses were changed in both.
I also changed the priority order from W-Fi/Ethernet, to Ethernet/WiFi. Hit apply, and now I cannot connect to the internet at all. I even rebooted my computer and could not connect using Safari or other browser. I went back in and changed the order back to WiFi first and now can connect with no problems. Status for both the WiFi and Ethernet sources/locations all showed green with no issues????

 

[MacInWin]

I checked the DNS server settings in both Wi-Fi and Ethernet, and the DNS service addresses were changed in both.
I also changed the priority order from W-Fi/Ethernet, to Ethernet/WiFi. Hit apply, and now I cannot connect to the internet at all. I even rebooted my computer and could not connect using Safari or other browser. I went back in and changed the order back to WiFi first and now can connect with no problems. Status for both the WiFi and Ethernet sources/locations all showed green with no issues????

That is very strange about the Ethernet. A green dot normally means it is connect and working just fine. What is the IP number assigned to the Ethernet interface? (Each interface has its own IP number.) Browsers use the DNS services to find things in the Internet, so if the DNS service is not working, you can have solid connections and still not get anything from the Internet.

Just to be sure, the changes you made to add the three DNS numbers I suggested were done AFTER you changed to Automatic, right? If not, you need to add them again with Automatic selected because each option in that box have their own settings. Yes, it's confusing, but that's how the Internet was set up.

 

[MacInWin]

BTW, the DNS numbers you gave are for Cox Communication, which I presume is your ISP. You should be able to add the three IP numbers I gave to that list, and to drag them to the top of the list so they get used first, if you want. That makes you independent of Cox for DNS and puts you into a more reliable DNS Service with lots of redundancy. Cox should have the same, but you never know.

 

[skays]

Don't have Cox. I have CenturyLink.
And if I go into System Preferences/Network and click on (high light) "Ethernet" location, this makes "Ethernet" the primary source from then on or until I reboot/restart my system?

 

[MacInWin]

Don't have Cox. I have CenturyLink.
And if I go into System Preferences/Network and click on (high light) "Ethernet" location, this makes "Ethernet" the primary source from then on or until I reboot/restart my system?

Well, the DNS numbers you have are from Cox Communications. That's another reason to change to the ones I provided.

Clicking on the interface does NOT change priority nor what the machine uses now or in the future. It's the order in which they are listed that determines which is used first. So do what I said in post #32 if you want to change the order. And the change doesn't take place until you click the "Apply" button.

 

[skays]

Thank you. I did all of that in the order/way you identified, but for some reason changing the priority order from WiFi - Ethernet to Ethernet - WiFi does not allow any browser to access the internet. Weird. Hopefully diagnostic tests tomorrow by certified Apple support tech will identify something. Hopefully when all said and done it will be a Netgear AP device issue and not my computer.
I do appreciate your time and guidance in this...as I do appreciate all that have commented and provided recommendations.

 

[MacInWin]

I would venture to say that the hardware on the Mac is working flawlessly. Nothing indicates anything other than that to me. It "might" be a software problem, but I'm seriously doubting that, too. It is most likely a setting that I'm not communicating properly to you, or something in the Netgear setup. Clearly, it's working for WiFi, not Ethernet, so for now, just disconnect the Ethernet and press on with it.

 

[pm-r]

It is most likely a setting that I'm not communicating properly to you, or something in the Netgear setup. Clearly, it's working for WiFi, not Ethernet, so for now, just disconnect the Ethernet and press on with it.

Have the internal access to the Netgear and its setup settings disabled the Ethernet ports perchance...???

Just a thought...


- Patrick
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