ASUS RT-N66U IPv6 with Merlin June 9, 2019

In a previous post I described how to get IPv6 working on the ASUS RT-N66U using the stock firmware. I’ve since switched to using the unofficial Merlin firmware.

While the settings in the previous article still apply, Merlin has more settings exposed and, at least in my case, failing to change the Prefix Length from the default 64 to 56 left IPv6 in a broken state. This led to various network issues such as avatars in the Twitter app taking forever to load, Steam being dog-slow on my Ubuntu 18.10 laptop etc.

Here are my current settings:

Connection type: Native
Interface: PPP
DHCP-PD: Enable
MTU: 1280

LAN Prefix Length: 56
Auto Configuration Setting: Stateless
Lifetime (sec): 86400

Connect to DNS Server automatically: Enable
Advertise router as IPv6 DNS server: Yes
Enable name resolution for fixed addresses: No

Enable Router Advertisement: Enable
Enable DHCPv6 Server: Enable

Enable IPv6 MTU advertisement: Yes
Release addresses on exit: Yes
Prefix delegation requires address request: No