Disabling IPv6 DNS advertising at GL-AX1800

Technical Support for Routers
1

I didn’t know what exact happened with my router but now every device in my network is getting ipv6 DNS address first after router’s one:

   DNS Servers . . . . . . . . . . . : fd1a:15fe:496f::1
                                       10.5.7.1

Waht was done so far:

  • disabled IPv6
  • delted WAN6 interface
  • odhcpd deamon stopped and disabled
  • all IPv6 settings are disabled at all interfaces

My Configs:

network

root@GL-AXT1800:~# cat /etc/config/network

config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth1'
        list ports 'eth2'
        option multicast_to_unicast '0'

config device
        option name 'eth1'
        option macaddr 'xx:xx:xx:xx:xx:xx'

config device
        option name 'eth2'
        option macaddr 'xx:xx:xx:xx:xx:xx'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option netmask '255.255.255.0'
        option isolate '0'
        option ipaddr '10.5.7.1'
        option delegate '0'
        option ipv6 '0'

config device
        option name 'eth0'
        option macaddr 'xx:xx:xx:xx:xx:xx'

config interface 'wan'
        option device 'eth0'
        option proto 'dhcp'
        option ipv6 '0'

config interface 'wan6'
        option device 'eth0'
        option proto 'dhcpv6'
        option disabled '1'

config switch
        option name 'switch0'
        option reset '0'
        option enable_vlan '0'

config interface 'guest'
        option force_link '1'
        option type 'bridge'
        option proto 'static'
        option ipaddr '192.168.9.1'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option multicast_querier '0'
        option igmp_snooping '0'
        option isolate '0'
        option bridge_empty '1'

config interface 'wwan'
        option proto 'dhcp'

config rule 'policy_bypass_vpn'
        option mark '0x60000/0x60000'
        option lookup '53'
        option priority '53'

config rule 'policy_via_vpn'
        option mark '0x80000/0x80000'
        option lookup '52'
        option priority '52'

config rule 'policy_dns'
        option mark '0x100000/0x100000'
        option lookup '51'
        option priority '51'

config interface 'wg2'
        option proto 'wireguard'
        option private_key 'xxxxx='
        option peerdns '0'
        list addresses '5.7.3.3/32'
        option mtu '1380'

config wireguard_wg2
        option description 'hm'
        option endpoint_host 'test.example.com'
        option route_allowed_ips '1'
        list allowed_ips '5.7.1.0/24'
        list allowed_ips '5.7.3.0/24'
        option public_key 'yyyyy='
        option endpoint_port '5382'
        option persistent_keepalive '60'

config interface 'wgclient'
        option proto 'wgclient'
        option config 'peer_5238'
        option disabled '1'

config device
        option name 'wg2'
        option multicast '1'

dhcp

root@GL-AXT1800:~# cat /etc/config/dhcp

config dnsmasq
        option domainneeded '1'
        option localise_queries '1'
        option expandhosts '1'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option localservice '1'
        option ednspacket_max '1232'
        option rebind_protection '0'
        option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
        option strictorder '1'
        option allservers '1'
        list server '/home.loc/5.7.1.1'
        option domain 'moro.loc'
        option local '/lan/'

config dhcp 'lan'
        option interface 'lan'
        option leasetime '12h'
        option dhcpv4 'server'
        option start '2'
        option limit '248'
        list ra_flags 'none'
        option dhcpv6 'disabled'
        option ra 'disabled'

config dhcp 'wan'
        option interface 'wan'
        option ignore '1'
        list ra_flags 'none'

config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
        option loglevel '4'

config dhcp 'guest'
        option interface 'guest'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv6 'disabled'
        option ra 'disabled'

config domain
        option ip '10.5.7.1'
        option name 'gl-inet'

but problem still persists, every new device mobile phone or PC are getting IPV6 address as well as IPv6 DNS with first priority anyway, how to get rid off it?

2

I finally got what was a problem: I had another OpenWRT router (at my virtual machines pool) which broadcasted that IPv6 stuff. After reconfiguring it similarly - IPv6 DNS problem was gone. What helped me to identify that machine: I opened a browser with that IPv6 DNS address every machine got from my master router (to do so you must encapsulate it with brackets [], like http://[fd1a:15fe:496f::1] and that opened a luci gui of that “second” router)

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