DNS server shows IPv6 instead of IPv4 for Ethernet adapter and Ethernet not working

Recently my Ethernet stopped working and when I ran ipconfig /all, it showed IPv6 addresses for the DNS servers instead of the usual IPv4. I don't know what the problem is and I can't find a solution on how to make it switch back to IPv4.

I don't remember making any changes to my computers network settings although I was coding with sockets earlier but that was over WiFi so I don't think that could have affected the Ethernet settings.

I have also tried uninstalling and reinstalling the driver and rebooting my computer but none of that seems to fix the problem. Any solutions?

DNS Servers . . . . . . . . . . . : 
fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1

here's my ipconfig /all output

J leong

Posted 2016-12-05T09:02:51.857

Reputation: 121

1Why do you assume the IPv6 address of the DNS server is the problem? – Seth – 2016-12-05T09:06:21.053

@Seth because I have googled it and I found one post where someone had ipv6 under the dns servers and their internet wasn't working. also under my wifi it is ipv4 for the dns servers – J leong – 2016-12-05T09:07:58.473

1What version of Windows are you using? Does your client have an IPv4 or IPv6 address? What do you mean your Ethernet doesn't work? You LAN internet connection? Can you reach other clients on the network? – Seth – 2016-12-05T09:11:37.783

@Seth i am unable to connect to the internet via ethernet cable. it shows those things under dns servers in the ipconfig /all. I don't know if it works over LAN. there is also no default gateway for the ethernet. – J leong – 2016-12-05T09:19:18.957

Sounds like your DHCP server isn’t working. Please provide the entire output of ipconfig /all, preferably only for the relevant network interface. – Daniel B – 2016-12-05T09:40:25.593

@DanielB i added the output – J leong – 2016-12-05T09:47:26.103

You could’ve just copied the text, but whatever. Your Ethernet connection isn’t getting an address from DHCP. That’s why it isn’t working. Windows calls this state “Limited connectivity”. Also, your internal IP addresses are not confidential information. – Daniel B – 2016-12-05T09:50:16.777

@DanielB ok but then how would I resolve this issue? the cable works with my friend's laptop so the problem has to be my computer. – J leong – 2016-12-05T09:53:59.400

oh wait nevermind i fixed it. i restarted my dhcp server as soon as you said that it could be a problem with that. Thanks for all your help Daniel! – J leong – 2016-12-05T09:54:54.590

Answers

There's something clearly wrong with your network. Your ipconfig output shows a link local address which essentially means you aren't getting an IP address at all. The fec0 addresses are the IPv6 equivalent of 169.254.x.x ( address which occur when you have some network connectivity, but there are issues with getting an IP address.

There are a few possibilities - there's something wrong with the IPv4 settings (double check these!) or your Ethernet adapter is borked. In this case, since you're not getting an IP address (which is the real issue), we can probably start there.

I'd try the Ethernet adapter with static settings as well. Since DHCP leases last a while renewing leases or restarting your router would be an idea.

Journeyman Geek

Posted 2016-12-05T09:02:51.857

Reputation: 119 122

Your Ethernet adapter config suggests a possible DHCP issue. DHCP is enabled on the client, but your IPv4 address is an APIPA address, suggesting that the client was unable to receive an address from the DHCP server. That would explain why the IPv6 addresses are listed for DNS Servers. Client often receive default gateway and DNS information via DHCP scope options.

The IPv6 addresses you listed are reserved site-local addresses (RFC 3879), which is deprecated, but for some still employed in cases like this. I hesitate to compare site-local addressing directly with APIPA, as link-local addresses are a closer comparison.

I was able to dig up an interesting article on site-local addresses. It explains the relationship between site-local addresses and DNS in more depth.

https://www.howfunky.com/2015/10/ipv6-site-local-addresses-why-are-those.html

All that to say, I would start looking at DHCP.

Jonathan McLaren

Posted 2016-12-05T09:02:51.857

Reputation: 111

What I find even more suspect is that it uses Cloudflare as DHCP server. – kasperd – 2019-01-16T00:13:01.010