Configure IPv6 for generic DSL dialup

Introduction

This short article shows how to setup IPv6 on a standard DSL connection and how to handover the delegated prefix from your provider in your local LAN.

It’s compatible and tested for but not limited to:

  • Deutsche Telekom

Step 1 - General Settings

Go to System->Settings->General-> and check that Prefer IPv4 over IPv6 is not ticked. This value is default so just check if it has been touched.

Also enable Allow DNS server list to be overridden by DHCP/PPP on WAN at the bottom, so you get the correct DNS servers if you just use IPv4 ones.

Step 2 - Allow IPv6

Next go to Firewall->Settings->Advanced and verfiy that Allow IPv6 is enabled.

Step 3 - Interface Configuration

In Interfaces->WAN and set IPv6 Configuration Type to DHCPv6 and in section DHCPv6 client configuration at the bottom tick:

  • Request only an IPv6 prefix
  • Send IPv6 prefix hint
  • Use IPv4 connectivity

Set the prefix size to the one your provider delegates, mostly /56 or 64, sometimes /48.

Then change to Interfaces->LAN and set IPv6 Configuration Type to Track Interface. At the bottom in section Track IPv6 Interface choose IPv6 Interface as WAN and for IPv6 Prefix ID a value of 0 is perfectly fine.

Hit Apply and disable/enable the NICs of your internal systems. Depending on the system and vendor, also a reboot could be required.