Example error: when we ran custom DNS server and we got the error:
root@tutorialspots ~ # node bindns.js
node:events:491
throw er; // Unhandled 'error' event
^
Error: bind EADDRINUSE 0.0.0.0:53
at node:dgram:362:20
at process.processTicksAndRejections (node:internal/process/task_queues:83:21)
Emitted 'error' event on Server instance at:
at Socket.<anonymous> (/root/node_modules/bindns/lib/ndns.js:341:43)
at Socket.emit (node:events:513:28)
at node:dgram:364:14
at process.processTicksAndRejections (node:internal/process/task_queues:83:21) {
errno: -98,
code: 'EADDRINUSE',
syscall: 'bind',
address: '0.0.0.0',
port: 53
}
Node.js v18.15.0
Port 53 already in use. How to free the port 53?
You are most likely affected by systemd-resolve
You can confirm if you are affect by systemd-resolve by checking listening ports and applications:
sudo netstat -tulpn | grep :53 | grep LISTEN
tcp 0 0 127.0.0.53:53 0.0.0.0:* LISTEN 510/systemd-resolve
systemd-resolve is listening on port 53.
How to stop systems-resolve using port 53?
Step 1: Edit /etc/systemd/resolved.conf set DNSStubListener to no, and set value of DNS and FallbackDNS
sudo nano /etc/systemd/resolved.conf
[Resolve] DNS=8.8.8.8 FallbackDNS=8.8.4.4 #Domains= #LLMNR=no #MulticastDNS=no #DNSSEC=no #DNSOverTLS=no #Cache=no-negative DNSStubListener=no #ReadEtcHosts=yes
Step 2: Create a symbolic link for /run/systemd/resolve/resolv.conf with /etc/resolv.conf
sudo ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf
Step 3: restart your server
