Port 53 on macos catalina "bind: address already in use"

[dzg]

Trying to set this up on macos catalina. Running from terminal with sudo.

No matter which interface I choose, I get "listen udp 192.168.1.55:53: bind: address already in use". Same for 5353.

sudo lsof -i :53 shows mdnsresponder using port 53.

After some digging ... seems port 53 is being used because I have Internet Sharing enabled. Any way to use this with Internet Sharing?

[ameshkov]

Tbh, I don't know if that's possible, and this is the first time this was asked here.

Marked as "help wanted", maybe someone can help with this.

[Kainichy]

Use this to disable mDNSresponder directly:
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.nDNSresponder.plist
But it may stop internet sharing. However you can have a try. To enable again:
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.nDNSresponder.plist

[MrDrache333]

Unload failed: 150: Operation not permitted while System Integrity Protection is engaged
But you also have to disable System Integrity Protection first.