I periodically experience a disconnection with my laptop. The connection period lasts about 3-6 minutes. I know for certain that the WiFi works fine.
Using the command
sudo journalctl --since="-2 minutes" I find that a recurring line is:
(...) Using degraded feature set UDP instead of TCP for DNS server 10.64.10.16.
What should I do ? I cannot work since the connection conditions are definitely unstable. I have recently noticed that it is a quite common problem.
I have ubuntu whose version is 21.04, and my laptop is an Acer Aspire 3 A315-56 with a WiFi connection.
systemd-resolved?) might be normally using DNSSEC/EDNS0, and using a TCP connection to DNS server because of this. When you have a connection problem, it notices TCP connection is failing and reverts to UDP and basic DNS protocol. But if you still experience a disconnection, that probably means the reversion to UDP is not helping, perhaps because the actual connection to the destination website (or whatever) still uses TCP and still fails. What is your basis for the conclusion that WiFi works fine? (I'm asking to exactly identify the known-good element(s).)
resolvconfwas missing. After that, as @harrymc suggested I have set
DNSSEC=off(commenting it out) through the command: sudo nano /etc/systemd/resolved.conf After that the cmd sudo systemctl restart systemd-resolved.service