[Solved] LAN clients no IPv6 (ra_mtu option in /etc/config/dhcp causes problems)

Hi, I reinstalled my RPI4 with a recent snapshot. Was running from last summer's snapshot rockstable, did not survive update, reinstalled new.
Ethernet is internal LAN, external WAN is a Ethernet<->USB thing being WAN. Connected to fibre modem doing DHCP.

The router has full IPv6 connectivity, ping all fine.

ip a:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br-lan state UP qlen 1000
    link/ether dc:a6:32:45:e1:c5 brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP qlen 1000
    link/ether d0:37:45:06:04:86 brd ff:ff:ff:ff:ff:ff
    inet 100.116.248.208/16 brd 100.116.255.255 scope global eth1
       valid_lft forever preferred_lft forever
    inet6 2a00:6020:1000:1f::7e2c/128 scope global dynamic noprefixroute
       valid_lft 3344sec preferred_lft 3344sec
    inet6 fe80::d237:45ff:fe06:486/64 scope link
       valid_lft forever preferred_lft forever
4: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether dc:a6:32:45:e1:c6 brd ff:ff:ff:ff:ff:ff
5: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether dc:a6:32:45:e1:c5 brd ff:ff:ff:ff:ff:ff
    inet 10.83.66.1/24 brd 10.83.66.255 scope global br-lan
       valid_lft forever preferred_lft forever
    inet6 2a00:6020:b2fe:1700::1/60 scope global dynamic noprefixroute
       valid_lft 3345sec preferred_lft 3345sec
    inet6 fd4b:c595:e481::1/60 scope global noprefixroute
       valid_lft forever preferred_lft forever
    inet6 fe80::dea6:32ff:fe45:e1c5/64 scope link
       valid_lft forever preferred_lft forever

The clients get no ipv6 addresses, I don't get it (only fe80:...).

cat /etc/config/network:


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

config globals 'globals'
        option ula_prefix 'fd4b:c595:e481::/48'
        option packet_steering '1'

config interface 'lan'
        option type 'bridge'
        option ifname 'eth0'
        option netmask '255.255.255.0'
        option proto 'static'
        option ip6assign '60'
        option ipaddr '10.83.66.1'

config interface 'WAN'
        option proto 'dhcp'
        option ifname 'eth1'

config interface 'WAN6'
        option proto 'dhcpv6'
        option ifname 'eth1'
        option reqaddress 'try'
        option reqprefix 'auto'

/etc/config/dhcp:

config dnsmasq
        option domainneeded '1'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option local '/lan/'
        option domain 'lan'
        option expandhosts '1'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
        option localservice '1'
        option ednspacket_max '1232'
        list server '/mig19.de/2a06:fb00:1::4400'

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option dhcpv6 'server'
        option ra 'server'
        option ra_slaac '1'
        list ra_flags 'managed-config'
        list ra_flags 'other-config'
        option ra_maxinterval '600'
        option ra_mininterval '200'
        option ra_lifetime '1800'
        option ra_mtu '0'
        option ra_hoplimit '0'
        option ra_management '1'

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

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

As said, I don not get it. From router point of view everything looks fine, what could be wrong here?

1 Like

You could remove these options, which have been likely added by LuCI without your explicit wishes. (due to a recent addition, and unnecessary addition logic was removed today)

4 Likes

You know what?
I removed those 5 options with vi(m), rebooted and got full IPv6 connectivity on my LAN clients back!
:kissing_smiling_eyes:

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