How to close TCP 443, TCP 80 and UDP 53 ports on ubuntu server?

Question

linux

When working on the server, an error occurred that these ports are occupied by other processes, how to release processes
Error type
[20:13:20] [!!!] Failed to start nameserver on port 53
[20:13:21] [!!!] listen tcp :443: bind: address already in use

Answer 1

To begin with, why is your DNS server going to listen on port 443?
To find out what process is listening on the port, you can use ss, netstatand similar utilities. Then, if you want to free the port, just turn off the corresponding service.

Answer 2

Failed to start nameserver on port 53

sudo systemctl stop systemd-resolved.service
sudo systemctl disable systemd-resolved.service