Self Assigned IP address on a Mac

24Hamish wrote:

I've tried the various solutions to this problem, posted on the Internet, removing various Plists, Renewing the DHCP Lease Time, but with no joy to-date!

The reason I went Network Hard wired, my home has very thick stone walls, with lots of wireless black spots?

This is my first Mac Computer and if I can't get a permanent fix, for this issue, I will be going back to Windows.

Have you replaced the ethernet cable from the Mac to the wall socket? Or directly to the switch?

If you are running via wall socket do try running a known good ethernet directly to the switch.

Constant issues with self assigned IP address is more likely a connection error.

Sometimes there are just strange incompatibilities..

My suggestion here using screenshots is from older Mac as I have no need to upgrade yet. It might look slightly different on the latest OS.

In the setup of ethernet go to advanced..

It will be set to automatic.. change it to manually.

No luck try setting the speed to 100

And still no luck you can also try 10baseT.

This is a good test because if 1000Mbps does not work but 100Mbit does then a pair is broken in the cable.. if 10 works then it is seriously bad cable issue.

I do not like where Apple put the ethernet port in the new iMac.. it is bad practice to have ethernet next to power let alone integrated into the power supply.

Another test is to use a very short patch cable to another gigabit switch.. a 5 or 8 port type is fine.. and that is plugged back to the main 24 port switch. If that fails get the Mac checked by apple.

The reason I went Network Hard wired, my home has very thick stone walls, with lots of wireless black spots?Hub4 WiFi works fine and links Mac and other WiFi devices.

Does your Mac computer connect to the network over Ethernet, or over Wi-Fi?

The Hub4......do you know how many different devices it will allow to connect to the network? Asked another way, do you know the DHCP range for the Hub4? If it has a limit of 10-12 devices, the Hub is running out of IP addresses.

In the 'Service Order', menu, I have Ethernet as first preferred choice, then WiFi.

If the Mac cannot connect via Ethernet, then you would want to have WiFi as the first choice in the connection order. Please make that change and test to see if things improve. If they don't we'll need to run some tests on the actual quality of the Wi-Fi signal that the Mac is receiving.

Although you are not using Ethernet for the Mac connection to the network, does the Mac have an Ethernet port that could be used temporarily to run some checks?

Not sure how much help we can provide, since we handle questions about the Apple routers in this support area. So far, it looks like you have a connection issue with your Mac. Which Mac do you have? It might be better if you post your question about the Mac in the support area for the Mac, but we'll try to help.

Disappointingly, I purchased all of the Ethernet cables, for my Network, already made up, to the lengths I required.

Lots of cheap ethernet pre-made cables are bad when you buy from cheap sources like ebay.

Even cables made to order can test OK when made but fail in service after a few bends and twists.. especially long patch cables which break the code. Maximum length stranded cable total is 5M from memory.

Always good to have another long working cable on hand.. and of course the cheap cable tester (just tests connectivity) are a great tool.

9 times out of 10, it is the cable or a connector on the cable that is the culprit in issues like this.