At times when using Laravel Valet for Linux DNS stops working. This is in spite of adding a custom name servers such as 184.108.40.206 to to /etc/resolv.conf. Upon closer inspection it seems resolv.conf is pointing towards Valet:
resolv.conf -> /opt/valet-linux/resolv.conf
To alleviate this issue, I had to temporary unlink the file at which point I stopped loosing my custom entries.