Internet not working properly when extended to another router

[fakemanhk]

Looking at your config, sounds like your provider also uses MAP-E as tunnel, recently I found a way to do it in OpenWrt without the need of ISP router, please try if my following guide works for you.

A guide for Japan NTT users on IPoE/IPv6 setting (MAP-E only)

For the fiber internet services in Japan, unless you are using 10G one (which is very new), most 1G fiber connections come with 2 ways of connection: PPPoE & IPoE. The PPPoE is IPv4 only (some providers have IPv6 PPPoE before but I think should be deprecated now) and it can be slow in busy hours or areas, also the PPPoE dialup speed really depends on router CPU single core speed so even my older x86 router cannot get better PPPoE speed. ISP has provided IPv6 which doesn't need any dialup, and t…