Disable IPv6

IPv6 and I are not the best friends, so I disable it wherever I can. The number of devices in my network is still convenient to handle with IPv4...

You have to edit the file /etc/default/grub:

sudo nano /etc/default/grub

... and edit resp. insert the following lines:

GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 quiet splash"
GRUB_CMDLINE_LINUX="ipv6.disable=1"

Afterwards execute:

sudo update-grub

... and reboot your PC