Disable IPv6 on Linux and OpenWRT

Let&see how and why disabling IPv6 on GNU/Linux systems and on OpenWRT routers. WARNING: disabling IPv6 may have unintended consequences. Services are designed to run in dual stack mode. If you want to run a server exclusively in IPv4 mode you&need to change lots of configuration files, potentially one for each service! Timestamps: 0:00 Intro 0:10 Reasons to disable IPv6 0:40 Disabling IPv6 on GNU/Linux and check if it works 1:19 Fix OpenSSH 1:42 Fix Unbound and notes on other services 2:00 Android problem with IPv6 DNS server and solution when using it with OpenWRT 2:31 Disable IPv6 on OpenWRT 2:57 Outtro #solvecomputerscience