You'll know if you have broken DNS if you do the following and get an error resolving the DNS name:
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host one.one.one.one
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ping 1.1.1.1
Check if you're seeing the following error as it is indicative of this specific bug:
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sudo systemctl status systemd-resolved.service
Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
Try the following fix:
First, note the existing configuration:
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$ ls -l /etc/resolv.conf
lrwxrwxrwx 1 root root 29 Aug 12 2017 /etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf
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sudo ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf
Then, restart systemd-resolved:
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sudo systemctl restart systemd-resolved.service
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sudo ln -sf /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
Background info about the fix:
Workaround is from:
https://www.linode.com/community/questi ... buntu-1804
Bug report:
https://github.com/systemd/systemd/issues/9833
Bug report and merged fix:
https://github.com/systemd/systemd/pull/9836
An Ask Ubuntu report about this issue:
https://askubuntu.com/questions/1063462 ... r-a-lookup