[SOLVED] Ethernet behaviour abnormal (stuck in 169.254.x.x)

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

I was using DHCP with mostly the standard setup. Recently when my system starts up, it gets the IP address 169.254.x.x and cannot ping to my router. It cannot connect to the Internet.

grknight · Retired Dev Joined: 20 Feb 2015 Posts: 1660

This is the fallback address assigned when a DHCP client cannot find a DHCP server.

As for the manual config, you added a new address but never removed the old one.
Try using 'ip address' to add, delete, replace and/or flush addresses more effectively.

Seriously try to find the real issue of why DHCP and other connectivity is not working

NeddySeagoon · Posted: Mon Dec 20, 2021 8:14 pm Post subject:

midnite,

Your system cannot contact the router for dhcpcd to set up your network, so it sets itself a link local address, that's the 169.254.0.0/16 range.
So why does it fail co connect to the router?

Is the router working with other devices?
Is the network cable faulty?
Do yon have several ethernet cards and the cable is connected to the wrong one?

That it fails after some manual setup points to a communication failure.
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Computer users fall into two groups:-
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midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

Dear grknight and NeddySeagoon,

Thank you very much for help.

I just tried ifconfig enp3s0 del 169.254.198.11. The ping is still issuing from 169.254.x.x

grknight · Retired Dev Joined: 20 Feb 2015 Posts: 1660

At this point, the dmesg output would be helpful to diagnose what is happening.

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

The "bad" part is, after I boot up my PC again, it gets the valid IP by DHCP now.

Even though I am not able to reproduce the error at the moment, the good part is I can SSH into my PC and get this dmesg. Any clues?

Line 1 - 500 of 971

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

Line 501 - 971

NeddySeagoon · Posted: Mon Dec 20, 2021 10:05 pm Post subject:

midnite,

Please use wgetpaste.

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

NeddySeagoon,

Thank you. i will use wgetpaste next time.

Yes my sound does not work. I hope to fix it later.

This PC does not have WiFi.

I did suspect it is my kernel configure problem. Here is my .config.

http://dpaste.com/CBJJWNMKS
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- midnite.

NeddySeagoon · Posted: Mon Dec 20, 2021 10:40 pm Post subject:

midnite,

Sound cards are in two parts. The interface to the PCI bus, that's

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

NeddySeagoon,

Thank you for helping me and explaining about the sound.

Any clues why I was not able to get the valid IP address?

As there is no WiFi hardware on this PC. How to remove the WiFi thus avoid the error messages?

Thanks a lot!
_________________
- midnite.

NeddySeagoon · Posted: Mon Dec 20, 2021 11:16 pm Post subject:

midnite,

Turn off

Jaglover · Posted: Mon Dec 20, 2021 11:44 pm Post subject:

midnite,

you can use ethtool to start diagnosing your problem, ethtool will tell you if everything is fine with physical connection.
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pietinger · Posted: Tue Dec 21, 2021 12:48 am Post subject:

midnite,

https://www.gigabyte.com/Motherboard/GA-B85M-D3H-A-rev-10/sp#sp
says your board has ALC892 so you need "realtek-codecs"

eccerr0r · Posted: Tue Dec 21, 2021 3:45 am Post subject:

TBH I hate Gigabyte's Ethernet. I have three Gigabyte boards, two of which have flaky onboard RTL8169 Ethernet ports. Sometimes does not enumerate and power cycles are needed to restore operation. Would be interesting to see if a PCI Ethernet works any better or not.

You might need to also check your routing table when changing ip address. This wasn't a problem in the past - but identical to the distant past...
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NeddySeagoon · Posted: Tue Dec 21, 2021 11:48 am Post subject:

eccerr0r,

I have four or so RTL8169 cards because they were on sale for £1 each. I've not had that trouble.
One built in card is not happy without its firmware but I knew that they were not the best when I bought them.
However, they are 33MHz PCI bus cards, so there is not much danger of them ever getting to 1Gb/sec either. :)

midnite,

I suspect you had connection problems and unplugging the cable and plugging it back in again fixed it.
Possibly only for about 6 months. The 'wiping' the contacts by unplugging the cable and plugging it back in will fix it for another 6 months or so.
If that's the case, the gold has worn off the working parts of one of the connectors. You will need a good microscope to see it and if its the socket part, you will need to destroy the socket to inspect it.
However, this unplugging the cable and plugging it back in, process can go on for many years.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

NeddySeagoon,

I have turned off the WiFi items. Now I get a smaller kernel. Thank you.

I know that sometimes unplug and replug fixes the problem, just like reboot would fix 90% of Windows problems. I doubt this is not my case this time. I tried reboot for a few times. I tried unplug and plug the same cable into my another laptop. I tried boot into the sysrescuecd. I also tried boot into Win7. The 169.254.x.x issue only happened in my Gentoo.

I understand it is illogical as it sounds. This problem happened a week ago also. In both cases, it happened after I reconfigured my kernel. Last time I rolled back to the previous kernel configure. This time it is solved suddenly by itself after a reboot after a few hours.

I cannot reproduce the issue not. But in case it happens again, I will check the messages from dmesg and ethtool.

Jaglover,

Thank you. I have installed ethtool. My Ethernet is fine for these two days. If it fails next time, I will have the tool for diagnose.

I have read about the master-slave mode. Yet I do not know which one to choose. It was at "preferred slave". Its status was at slave, now the status is at master. The network works fine in both cases. Should I choose "preferred master" if I think my PC is more reliable than my router (i.e. the link partner)?

pietinger,

Thank you. I have added realtek-codecs into the kernel. Yet I am still having problem to start the KDE Plasma. I will open another thread to ask, and I will test the sound later.

eccerr0r,

Thank you for advises. But I think in my case, it was a problem with my software configurations, rather than the hardware. It is because I tried to boot into sysrescuecd, and Windows 7, they did not have a problem on the Ethernet.

I may get an extra PCI Ethernet card later for more reliable connections.
_________________
- midnite.

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

Dear all who have been generously helping me,

After 30+ hours of emerge, I could not get the correct IP again after a reboot. Then I was away for like an hour. The network is back to normal after a second startup. To me it feels like my router is blocking my box whenever after an extended hours of emerge. It is a cheap router away. There is even no proper logs of blocking or DHCP. I will switch to a better router soon. So we will see if the strange IP problem happens to the better router as well.

The output of ethtool enp3s0 was the same as normal when I could not get the correct IP.

midnite · Guru Joined: 09 Apr 2006 Posts: 435 Location: Hong Kong

This is the solution. The clock of my cheap router is always wrong.

pjp · Administrator Joined: 16 Apr 2002 Posts: 20067

NeddySeagoon · Posted: Sat Dec 25, 2021 10:49 am Post subject:

midnite,

Even cheap routers have an option to set the time using NTP (Network Time Protocol)
Find it and enable it.
You need to set this up on your Gentoo too.

Its unlikely that the firewall in your router will block NTP but you never know :)
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.