22.03.3 Not Requesting IPv6 Prefix for Delegation

I upgraded from 19.07.10 to 22.03.3 recreating my entire config. I no longer get a prefix which can be delegated although the config should be fine (checked it by diffing the old backup with the new config).

Currently I have the assumption, that the dhcp6 client is not even requesting a prefix to delegate, but I might be wrong here.

09:39:31.757885 IP6 (flowlabel 0x1a99f, hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::7683:c2ff:fe4a:1b06 > ff02::2: [icmp6 sum ok] ICMP6, router solicitation, length 16
          source link-address option (1), length 8 (1): 74:83:c2:4a:1b:06
09:39:31.763809 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 128) fe80::ae22:5ff:fe7e:1c83 > fe80::7683:c2ff:fe4a:1b06: [icmp6 sum ok] ICMP6, router advertisement, length 128
        hop limit 64, Flags [other stateful], pref high, router lifetime 1800s, reachable time 0ms, retrans timer 0ms
          prefix info option (3), length 32 (4): 2a02:908:820:4434::/64, Flags [onlink, auto], valid time 80367s, pref. time 37167s
          route info option (24), length 24 (3):  2a02:908:820:4434::/64, pref=medium, lifetime=86400s
          rdnss option (25), length 40 (5):  lifetime 360s, addr: 2a02:908:2:b::1 addr: 2a02:908:2:a::1
          mtu option (5), length 8 (1):  1500
          source link-address option (1), length 8 (1): ac:22:05:7e:1c:83
09:39:34.060660 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 32) :: > ff02::1:ff4a:1b06: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2a02:908:820:4434:7683:c2ff:fe4a:1b06
          unknown option (14), length 8 (1):
          0x0000:  0bd5 a6da af72
09:39:34.630601 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 32) :: > ff02::1:ff06:1450: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2a02:908:820:4434:3c4c:2503:4906:1450
          unknown option (14), length 8 (1):
          0x0000:  584d 3078 a977

Interface

# ifstatus wan6
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "uptime": 445,
        "l3_device": "eth0",
        "proto": "dhcpv6",
        "device": "eth0",
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [

        ],
        "ipv6-address": [
                {
                        "address": "2a02:908:820:4434:3c4c:2503:4906:1450",
                        "mask": 128,
                        "preferred": 42756,
                        "valid": 85956
                },
                {
                        "address": "2a02:908:820:4434:7683:c2ff:fe4a:1b06",
                        "mask": 64,
                        "preferred": 36721,
                        "valid": 79921
                }
        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {

Configuration:

config interface 'wan6'
	option device 'eth0'
	option proto 'dhcpv6'
	option reqaddress 'try'
	option reqprefix 'auto'

config dhcp 'lan'
	option interface 'lan'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'

config interface 'lan'
	option proto 'static'
	option netmask '255.255.255.0'
	option ipaddr '10.1.1.1'
	option ip6assign '64'
	option device 'br-lan.1'

Do you have any ideas what I can check or try? Thanks a lot already!

What you captured is router solicitation and advertisement. This isn't DHCP. Capture udp 547 for dhcp6.
Also, what is the wan interface configuration?

Hi @trendy ,

Thanks for the quick reply. In the meanwhile I played around with IPv6 relaying but then also got the upstream DNS servers which posed other issues for me.

To get another capture I reverted the settings back to the ones above and magically it works now as it did in 19.07.

I have no real explanation other than I messed up something else before :wink:

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