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OpenWRT IPv6 configuration for Xiaomi router 3 pro

Configure ULA

In the file located at /etc/config/network, we should check that option ula_prefix exists. Otherwise, we should generate a ULA prefix according to RFC 4193.

I use https://unique-local-ipv6.com/ to generate a valid ULA prefix.

config globals 'globals'
        option packet_steering '1'
        option ula_prefix 'fdda:59a8:b467::/48'

Configure DHCPv6

  • Luci -> Network -> Interface-> lan -> Edit -> Advanced Settings

set IPv6 prefix filter to "local (Local ULA)"

  • Luci -> Network -> Interface-> lan -> Edit -> DHCP server -> IPv6 Settings

set RA-Service (Route Advertisement Service) to "server mode" set DHCPv6-Service to "server mode"

  • Luci -> Network -> Interface-> lan -> Edit -> DHCP server -> IPv6 RA settings

set Default router to "forced" disable SLAAC i.e uncheck "Enable SLAAC" select both M (managed config) and O (other config) in RA flags option

Configure WAN6

  • Luci -> Network -> Interface-> wan6 -> Edit -> Advanced Settings

uncheck IPv6 source routing option

Configure firewall for NAT66

  • Luci -> Network -> Firewall -> Zones -> [WAN => REJECT] -> edit-> Advanced settings

check IPv6 masquerading option

Restart Router Network

Network and Firewall service are required to restart in order to make changes take effect.

service network restart
service firewall restart

Or simply reboot the router via reboot

Change the prefixpolicy on Windows

We use netsh int ipv6 show prefixpolicies to query the prefix policies. Below block shows an example output. Windows would send network requests via different prefix according to its precedence. Prefix with larger precedence will be tried first.

Precedence  Prefix         
----------  -------------
    50  ::1/128        Localhost
    40  ::/0           Native IPv6
    35  ::ffff:0:0/96  IPv4
    30  2002::/16      6to4
        5  2001::/32      Teredo
        3  fc00::/7       ULAs
        1  fec0::/10      site-local
        1  3ffe::/16      6bone
        1  ::/96          IPv4compat

Use command netsh int ipv6 set prefixpolicy fc00::/7 37 13 with administartor permission to overwrite default policy. Then, the policy should be set as shown below.

Precedence  Prefix         
----------  -------------
    50  ::1/128        
    40  ::/0           Native IPv6
    37  fc00::/7       ULAs <---------- from 3 up to 37
    35  ::ffff:0:0/96  IPv4
    30  2002::/16      
        5  2001::/32      
        1  fec0::/10      site-local
        1  3ffe::/16      
        1  ::/96

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