Help! -> iMac Internet Dead / no IP, both Windows and MacOS

[DrRadon]

Hey,

the internet died a few hours ago on my 2012 iMac.

The Problem occurs both using my AirPort/TimeCapsule wLan as well as my flats Telekom Router wLan.
The Problem occurs both on MacOS as well as on Windows using Bootcamp.
The Problem only occurs on my iMac, at least three other devices are doing just fine with them wLans.

At first it was just the message that my ip xxx.xxx.xxx.xxx was already taken by another device.
This never happened before, but i dident make a big fuzz out of it and started googling to fix it.

The main solution here seems to renewer the DHCP lease. That dos not work out. The deal here is... when i look at my MacBook all the spaces here are occupied with numbers IPv4, Netmask (paraphrasing from german here), Router. All Numbers. On my iMac there are no numbers, all these fields are empty and not filling up.
I tried setting this manually, but whatever numbers i put in there i immediately get the message of "Another device in the network already uses the IP of your Computer".
I also tried other fun stuff like wiggling the cables, rebooting the router, the computer n all but nothing change.


Because this happens in both MacOS and Windows (via Bootcamp) i am afraid something might have cracked on the inside despite there not being any heavy load when it happened.

Can anyone try to trouble shoot this with me?

 

[casperes1996]

Could you put a screenshot of the section where you say your iMac has nothing filled in? It’s OK to keep it in German

Is the drop down set to DHCP?

Last month or so I had a weird issue myself where the DHCP server on my modem cracked up entirely. It would work fine with devices that had already been connected, but anything that requested a new DHCP address would get garbage information back. I had to reset the modem completely and set it up anew to fix it.

It would send an iPad address to my MacBook, but not a ”correct” one. It would not send out a lot of information for the other fields, so things like the subnet mask remained empty, and the router address was also empty. Might be a similar issue

 

[DrRadon]

Is the drop down set to DHCP?

Hey, thank you for your reply.

Yes it is set to DHCP. I tried to work around with the manual stuff but it did not work out.
DHCP seemed to have worked before and on my MacBook its still working.

Attached is the screenshot you asked for. There is just nothing showing up even if i keep it open for a while.
This seems to be worse on the TimeCapsule as i seem to sometimes be able to get a connection with the Telekom router for a short while in MacOS. In Windows it worked as well on the Telekom Router, no idea how long, just did a quick test.

I did try a SMC reset and a NVRAM or PRAM reset because someone on a german board suggested it.
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Second picture is using the telekom router. Numbers show up, than it says IP is in use, but aperently mostly is working for webpages while spotify dos not play music

 

[casperes1996]

Right. Aside from pure DHCP there should be an option titled something like DHCP with manual address; So not full manual, but DHCP with manual address. Try that one, and all the fields should remain the same except for IPv4 address. Try and setting only the bit after the last "." too something else; So like 192.168.2.156

But otherwise I'd recommend resetting your Telekom router/modem. It's possibly got a messed up DHCP server that doesn't know what Its are taken and which aren't and may also have sent bad configuration data to your TC.

 

[DrRadon]

I ried DHCP with manual Adress, but nothing was showing up in the other fields.
I restarted the time capsule.
I´ll try a restart of the Telekom router in the morning.

 

[DrRadon]

The problem now also is happening on my MacBook.
But this morning it seems isolated to only the TimeCapsule. Telekom Router works without problem. So it might be something with the time capsules airport.

 

[DrRadon]

I think i solved the problem by disconnecting the repeater.
The repeater was not in the time capsule network but in the Telekom Routers network. But when i turned it of everything was working again and now i changed its ip to a manual one that is far away and it seems to not interfere anymore.

Wacky enough my iMac has no Sound via the 3.5 speakers i attached. Noticed that yesterday already. Why on earth would that happen in this context?
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Speakers still work if i attach them to my MacBook

 

[DrRadon]

Ok. Fixed the audio as well. For some reason "audio off" got a checkmark. Don't ask me why.

Problem solved. Thanks for the help.

 

[casperes1996]

Ok. Fixed the audio as well. For some reason "audio off" got a checkmark. Don't ask me why.

Problem solved. Thanks for the help.

Cheers. Glad you got everything sorted