Dhcpv6 and ra relay - DNSv6 not Advertised to end-clients

I have a problem where client devices do not have any IPv6 DNS. The end-clients (devices connected to the router directly, either via lan or via wifi) only show as the DNS. Since I have set the dhcpv6, ra and ndp to relay, I ideally wanted the IPV6 DNS servers to be passed to any end-clients. Can you kindly help me to resolve this issue?

The router has indeed received IPv6 DNS servers from the ISP automatically, which I can confirm both Both router and end-clients can ping6 IPV6 and ping IPV4 addresses. End-clients can access ipv4 and ipv6 websites without any problem.

Both the router (interface WAN6) and end client are show their automatically assigned global IPV6 addresses. Router's interface WAN has an IPV4 address assigned. End-clients have one local IPV4 addresses (192.168.0.X, assigned automatically by the router).

Configuration: WAN6 is connected via DHCPv6 and WAN is connected via ds-lite.

LEDE version: LEDE Reboot 17.01.2 r3435-65eec8bd5f
Router Hardware: WRT1900AC V1 mamba

These are my files used for configuration. Am I missing something? Thanks in advance for your help

Note: Some details such as IP addresses are anonymized for privacy reasons

config dnsmasq
option domainneeded '1'
option filterwin2k '0'
option localise_queries '1'
option rebind_protection '1'
option rebind_localhost '1'
option local '/lan/'
option domain 'lan'
option expandhosts '1'
option nonegcache '0'
option authoritative '1'
option readethers '1'
option leasefile '/tmp/dhcp.leases'
option resolvfile '/tmp/resolv.conf.auto'
option localservice '1'
option boguspriv '0'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option ra 'relay'
	#tried ra 'hybrid', uncommenting ra_management and list dns commented out below but did not have impact
	option dhcpv6 'relay'
	option ndp 'relay'
	# these did not have any impact even when hybrid mode was used
	#option ra_management '1'
	#list dns 'xxxx:xxx:xxxx:x::x'
	#list dns 'xxxx:xxx:xxxx:x::y'

config dhcp 'wan'
	option interface 'wan'
	option ignore '1'

config dhcp 'wan6'
	option dhcpv6 'relay'
	option ra 'relay'
	option ndp 'relay'
	option master '1'

config odhcpd 'odhcpd'
	option leasefile '/tmp/hosts/odhcpd'
	option leasetrigger '/usr/sbin/odhcpd-update'
	option maindhcp '1'


config interface 'loopback'
	option ifname 'lo'
	option proto 'static'
	option ipaddr ''
	option netmask ''

config globals 'globals'

config interface 'lan'
	option type 'bridge'
	option ifname 'eth0'
	option proto 'static'
	option netmask ''
	#option ip6assign '60'
	option ipaddr ''

config interface 'wan'
	option ifname 'eth1'
	option _orig_ifname 'eth1'
	option proto 'dslite'
	option 'peeraddr' 'gw.aaa.com'

config interface 'wan6'
	option ifname 'eth1'
	option proto 'dhcpv6'

config switch
	option name 'switch0'
	option reset '1'
	option enable_vlan '1'

config switch`_`vlan
	option device 'switch0'
	option vlan '1'
	option ports '0 1 2 3 5'

config switch_vlan
	option device 'switch0'
	option vlan '2'
	option ports '4 6'

search lan
nameserver ::1

# Interface wan6
nameserver xxxx:xxx:xxxx:x::x
nameserver xxxx:xxx:xxxx:x::y
search aa.com
search bb.com

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I am also facing the same problem. Everything is working fine but Router does not forward DNSv6 Server to clients which it got from ISP. Router forwards its Link Local IP address as DNSv6 server in RA.

Did you configure those Announced DNS servers in the LAN DHCP settings?


No, I did not configure anything. But as IPv6 is public IP address, It should get Public DNS server not Router's Link-local IP address.

1 Like