WRT1900AC v1 not receiving DHCPv6 IP6 assignment / OpenWrt 18.06.4 service release

[chuacw]

I'm using WRT1900AC v1, so according to [https://openwrt.org/toh/linksys/linksys_wrt1900ac](http://OpenWRT Linksys WRT1900AC), eth1 is WAN.

I'm running 18.06.4 the service release, flashed using factory image, not sysupgrade.

Using these commands:
odhcp6c -s /lib/netifd/dhcpv6.script -Ntry -P0 -t120 eth1.2
tcpdump -i eth1 -n -vv '(udp port 546 or 547) or icmp6'

I get from odhcp6c:
Command failed: Not found

and I'm not seeing any dhcpv6 solicit messages being sent on eth1.

If I reverse the direction, and try it on eth0,
odhcp6c -s /lib/netifd/dhcpv6.script -Ntry -P0 -t120 eth0
tcpdump -i eth0 -n -vv '(udp port 546 or 547) or icmp6'

I see the dhcp6 solicit message being sent on eth0.
07:40:23.114875 IP6 (flowlabel 0x5a86f, hlim 1, next-header UDP (17) payload length: 114) fe80::xxxx:xxxx:xxxx:4775.546 > ff02::1:2.547: [bad udp cksum 0x09ee -> 0x558b!] dhcp6 solicit (xid=9dff08 (elapsed-time 3125) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_82 opt_83 opt_94 opt_95 opt_96 server-unicast) (client-ID hwaddr type 1 b4750ef94775) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))

Why is odhcp6c unable to send dhcpv6 messages on eth1.2?
Any ideas anyone?

I've tried flushing the ip6tables, but there's still no dhcpv6 messages being sent.

[anon50098793]

ubus call network.interface notify_proto '{ "action": 0, "link-up": false, "keep": false, "interface": "" }

Please post sanitized ( in code tags ^ < / > );

uci show network

and try

odhcp6c -s /lib/netifd/dhcpv6.script -Ntry -P0 -t120 wan6

[chuacw]

Thanks for your response, @anon50098793.

Can you tell me what this command does? You're missing a quote ' at the end right?

ubus call network.interface notify_proto '{ "action": 0, "link-up": false, "keep": false, "interface": "" }'

uci show network:

root@OpenWrt:~# uci show network
network.loopback=interface
network.loopback.ifname='lo'
network.loopback.proto='static'
network.loopback.ipaddr='127.0.0.1'
network.loopback.netmask='255.0.0.0'
network.globals=globals
network.globals.ula_prefix='fd16:xxxx:xxxx::/48'
network.lan=interface
network.lan.type='bridge'
network.lan.ifname='eth0.1'
network.lan.proto='static'
network.lan.ipaddr='xxx.xxx.xxx.xxx'
network.lan.netmask='255.255.255.0'
network.lan.ip6assign='60'
network.wan=interface
network.wan.proto='dhcp'
network.wan.ifname='eth1.2'
network.wan6=interface
network.wan6.proto='dhcpv6'
network.wan6.reqaddress='try'
network.wan6.reqprefix='auto'
network.wan6.ifname='eth1.2'
network.@switch[0]=switch
network.@switch[0].name='switch0'
network.@switch[0].reset='1'
network.@switch[0].enable_vlan='1'
network.@switch_vlan[0]=switch_vlan
network.@switch_vlan[0].device='switch0'
network.@switch_vlan[0].vlan='1'
network.@switch_vlan[0].ports='0 1 2 3 5t'
network.@switch_vlan[0].vid='1'
network.@switch_vlan[1]=switch_vlan
network.@switch_vlan[1].device='switch0'
network.@switch_vlan[1].vlan='2'
network.@switch_vlan[1].ports='4 6t'
network.@switch_vlan[1].vid='2'

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 state UP qlen 532
    link/ether b4:xx:xx:xx:xx:75 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::xxxx:xxxx:xxxx:4775/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 532
    link/ether b4:xx:xx:xx:xx:75 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::xxxx:xxxx:xxxx:4775/64 scope link
       valid_lft forever preferred_lft forever
12: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether b4:xx:xx:xx:xx:75 brd ff:ff:ff:ff:ff:ff
    inet 192.xxx.xxx.xxx/24 brd 192.xxx.xxx.255 scope global br-lan
       valid_lft forever preferred_lft forever
    inet6 fd16:xxxx:xxxx::1/60 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::xxxx:xxxx:xxxx:4775/64 scope link
       valid_lft forever preferred_lft forever
13: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-lan state UP qlen 1000
    link/ether b4:xx:xx:xx:xx:75 brd ff:ff:ff:ff:ff:ff
15: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br-lan state UP qlen 1000
    link/ether b4:xx:xx:xx:xx:76 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::xxxx:xxxx:xxxx:4776/64 scope link
       valid_lft forever preferred_lft forever
16: wlan1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br-lan state UP qlen 1000
    link/ether b4:xx:xx:xx:xx:77 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::xxxx:xxxx:xxxx:4777/64 scope link
       valid_lft forever preferred_lft forever
17: eth1.2@eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether b4:xx:xx:xx:xx:75 brd ff:ff:ff:ff:ff:ff
    inet xxx.xxx.xxx.xxx/18 brd xxx.xxx.xxx.255 scope global eth1.2
       valid_lft forever preferred_lft forever
    inet6 fe80::xxxx:xxxx:xxxx:4775/64 scope link
       valid_lft forever preferred_lft forever

The settings for this device has been reset and totally wiped, so there's no customizations.

[anon50098793]

see:

Understanding pushing IPv6 to LAN

Interesting. However I managed a way to setup this. Unsure if I am making a big mistake or not. My ISP provides the following: [image] And if I setup ip6prefix - (Custom delegated IPv6-prefix) /etc/config/network like this: config interface 'wan6' option ifname 'eth1.2' option proto 'dhcpv6' option reqaddress 'try' option reqprefix 'auto' option ip6prefix '2001:818:deef:XXXXX::/56' (xxxx is an alias for privacy) And /etc/config/dhcp ndp (NDP-Proxy) to hybrid (keeping everything els…

luci might be a bit buggy with ipv6 params me thinks... ( guessing your running release? )

try adding under wan6 in /etc/config/network;

option reqaddress 'try'
option reqprefix 'auto'

then

/etc/init.d/network restart

otherwise have a read of that thread..... my ISP don't do ipv6 so can't test anything....

@chuacw

Can you tell me what this command does?

This is what is run when you ran your odhcp6c command above;

############ EDIT > /lib/netifd/dhcpv6.script@top
#!/bin/sh
set -x
echo "ODHCPD6c-`date +%Y%m%d-%H%M`: $*" >> /tmp/o6cout.txt

[chuacw]

Hi,

Thanks for your help. It's fine that you can't test it on your end.

root@OpenWrt:~# ubus call network.interface notify_proto '{ "action": 0, "link-up": false, "keep": false, "interface": "" }'
Command failed: Not found

odhcp6c -s /lib/netifd/dhcpv6.script -Ntry -P0 -t120 wan6

There's no visible output for this. Do I need to stop and change the wan6 interface to unmanaged before running the above command, or do anything before running the command?

[anon50098793]

@chuacw

ubus call network.interface notify_proto '{ "action": 0, "link-up": false, "keep": false, "interface": "" }'

You don't run this.... odhcp6c does (when you specify ethX)... it's why you got the command not found in your initial post.....

[anon50098793]

@chuacw

There's no visible output for this

logread

[chuacw]

The date/time specified is UTC/GMT, with no offset.

Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + date '+%Y%m%d-%H%M'
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + echo 'ODHCPD6c-20190714-0854: eth1.2 ra-updated'
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + '[' -z ra-updated ]
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + . /lib/functions.sh
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + N='
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): '
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + _C=0
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + NO_EXPORT=1
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + LOAD_STATE=1
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + LIST_SEP=' '
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + reset_cb
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + '[' -z  -a -f /lib/config/uci.sh ]
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + . /lib/config/uci.sh
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + CONFIG_APPEND=
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + . /lib/netifd/netifd-proto.sh
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + NETIFD_MAIN_DIR=/lib/netifd
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + PROTO_DEFAULT_OPTIONS='defaultroute peerdns metric'
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + . /usr/share/libubox/jshn.sh
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + . /lib/netifd/utils.sh
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + N='
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): '
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + '[' -n  ]
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + '[' -f /etc/odhcp6c.user ]
Sun Jul 14 08:54:07 2019 daemon.notice netifd: wan6 (14128): + exit 0
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + date '+%Y%m%d-%H%M'
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + echo 'ODHCPD6c-20190714-0854: eth1.2 ra-updated'
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + '[' -z ra-updated ]
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + . /lib/functions.sh
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + N='
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): '
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + _C=0
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + NO_EXPORT=1
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + LOAD_STATE=1
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + LIST_SEP=' '
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + reset_cb
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + '[' -z  -a -f /lib/config/uci.sh ]
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + . /lib/config/uci.sh
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + CONFIG_APPEND=
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + . /lib/netifd/netifd-proto.sh
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + NETIFD_MAIN_DIR=/lib/netifd
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + PROTO_DEFAULT_OPTIONS='defaultroute peerdns metric'
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + . /usr/share/libubox/jshn.sh
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + . /lib/netifd/utils.sh
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + N='
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): '
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + '[' -n  ]
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + '[' -f /etc/odhcp6c.user ]
Sun Jul 14 08:54:27 2019 daemon.notice netifd: wan6 (14128): + exit 0
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + date '+%Y%m%d-%H%M'
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + echo 'ODHCPD6c-20190714-0854: eth1.2 ra-updated'
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + '[' -z ra-updated ]
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + . /lib/functions.sh
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + N='
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): '
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + _C=0
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + NO_EXPORT=1
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + LOAD_STATE=1
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + LIST_SEP=' '
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + reset_cb
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + '[' -z  -a -f /lib/config/uci.sh ]
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + . /lib/config/uci.sh
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + CONFIG_APPEND=
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + . /lib/netifd/netifd-proto.sh
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + NETIFD_MAIN_DIR=/lib/netifd
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + PROTO_DEFAULT_OPTIONS='defaultroute peerdns metric'
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + . /usr/share/libubox/jshn.sh
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + . /lib/netifd/utils.sh
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + N='
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): '
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + '[' -n  ]
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + '[' -f /etc/odhcp6c.user ]
Sun Jul 14 08:54:36 2019 daemon.notice netifd: wan6 (14128): + exit 0

root@OpenWrt:~# cat /tmp/o6cout.txt
ODHCPD6c-20190714-0850: eth1.2 ra-updated
ODHCPD6c-20190714-0850: eth1.2 ra-updated
ODHCPD6c-20190714-0851: eth1.2 ra-updated
ODHCPD6c-20190714-0851: eth1.2 ra-updated
ODHCPD6c-20190714-0851: eth1.2 ra-updated
ODHCPD6c-20190714-0851: eth1.2 ra-updated
ODHCPD6c-20190714-0852: eth1.2 ra-updated
ODHCPD6c-20190714-0852: eth1.2 ra-updated
ODHCPD6c-20190714-0852: eth1.2 ra-updated
ODHCPD6c-20190714-0853: eth1.2 ra-updated
ODHCPD6c-20190714-0853: eth1.2 ra-updated
ODHCPD6c-20190714-0853: eth1.2 ra-updated
ODHCPD6c-20190714-0854: eth1.2 ra-updated

[anon50098793]

for tcpdump

tcpdump -i eth1.2 -n -vv 'ip6'

ifdown wan6
ifstatus wan6
ifup wan6
ifstatus wan6

[chuacw]

root@OpenWrt:~# tcpdump -i eth1.2 -n -vv 'ip6'
tcpdump: listening on eth1.2, link-type EN10MB (Ethernet), capture size 262144 bytes
09:05:40.992503 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) 2401:xxxx:xxxx::xxx > fe80::xxxx:xxxx:xxx:bf4: [icmp6 sum ok] ICMP6, neighbor advertisement, length 24, tgt is fe80::xxxx:xxxx:xxx:6402, Flags [router, solicited]
09:05:54.475985 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::xxxx:xxxx:xxx:6402 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 24
        hop limit 64, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 0s, retrans time 0s
          source link-address option (1), length 8 (1): c0:xx:xx:xx:xx:02
            0x0000:  c0xx xxxx xx02
09:06:09.152847 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) 2401:xxxx:xxxx::xxx > fe80::xxxx:xxxx:xxx:bf4: [icmp6 sum ok] ICMP6, neighbor advertisement, length 24, tgt is fe80::xxxx:xxxx:xxx:6402, Flags [router, solicited]
09:06:13.600097 IP6 (flowlabel 0xc5dc2, hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::xxxx:xxxx:xxx:4775 > ff02::2: [icmp6 sum ok] ICMP6, router solicitation, length 16
          source link-address option (1), length 8 (1): b4:xx:xx:xx:xx:75
            0x0000:  b4xx xxxx xx75
09:06:13.604527 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::xxxx:xxxx:xxx:6402 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 24
        hop limit 64, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 0s, retrans time 0s
          source link-address option (1), length 8 (1): c0:xx:xx:xx:xx:02
            0x0000:  c0xx xxxx xx02
09:06:13.881816 IP6 (flowlabel 0x5a86f, hlim 1, next-header UDP (17) payload length: 114) fe80::xxxx:xxxx:xxx:4775.546 > ff02::1:2.547: [bad udp cksum 0x09ee -> 0x930a!] dhcp6 solicit (xid=39ce22 (elapsed-time 0) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_82 opt_83 opt_94 opt_95 opt_96 server-unicast) (client-ID hwaddr type 1 b4750ef94775) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
09:06:15.024921 IP6 (flowlabel 0x5a86f, hlim 1, next-header UDP (17) payload length: 114) fe80::xxxx:xxxx:xxx:4775.546 > ff02::1:2.547: [bad udp cksum 0x09ee -> 0x9298!] dhcp6 solicit (xid=39ce22 (elapsed-time 114) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_82 opt_83 opt_94 opt_95 opt_96 server-unicast) (client-ID hwaddr type 1 b4750ef94775) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
09:06:15.597618 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::xxxx:xxxx:xxx:6402 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 24
        hop limit 64, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 0s, retrans time 0s
          source link-address option (1), length 8 (1): c0:xx:xx:xx:xx:02
            0x0000:  c0xx xxxx xx02
09:06:17.264889 IP6 (flowlabel 0x5a86f, hlim 1, next-header UDP (17) payload length: 114) fe80::xxxx:xxxx:xxx:4775.546 > ff02::1:2.547: [bad udp cksum 0x09ee -> 0x91b8!] dhcp6 solicit (xid=39ce22 (elapsed-time 338) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_82 opt_83 opt_94 opt_95 opt_96 server-unicast) (client-ID hwaddr type 1 b4750ef94775) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
09:06:17.814742 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::xxxx:xxxx:xxx:6402 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 24
        hop limit 64, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 0s, retrans time 0s
          source link-address option (1), length 8 (1): c0:xx:xx:xx:xx:02
            0x0000:  c0xx xxxx xx02
09:06:19.281237 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::xxxx:xxxx:xxx:6402 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 24
        hop limit 64, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 0s, retrans time 0s
          source link-address option (1), length 8 (1): c0:xx:xx:xx:xx:02
            0x0000:  c0xx xxxx xx02
09:06:21.904917 IP6 (flowlabel 0x5a86f, hlim 1, next-header UDP (17) payload length: 114) fe80::xxxx:xxxx:xxx:4775.546 > ff02::1:2.547: [bad udp cksum 0x09ee -> 0x8fe8!] dhcp6 solicit (xid=39ce22 (elapsed-time 802) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_82 opt_83 opt_94 opt_95 opt_96 server-unicast) (client-ID hwaddr type 1 b4750ef94775) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
09:06:31.104934 IP6 (flowlabel 0x5a86f, hlim 1, next-header UDP (17) payload length: 114) fe80::xxxx:xxxx:xxx:4775.546 > ff02::1:2.547: [bad udp cksum 0x09ee -> 0x8c50!] dhcp6 solicit (xid=39ce22 (elapsed-time 1722) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_82 opt_83 opt_94 opt_95 opt_96 server-unicast) (client-ID hwaddr type 1 b4750ef94775) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
09:06:34.887971 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::xxxx:xxxx:xxx:6402 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 24
        hop limit 64, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 0s, retrans time 0s
          source link-address option (1), length 8 (1): c0:xx:xx:xx:xx:02
            0x0000:  c0xx xxxx xx02
09:06:34.965793 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) 2401:xxxx:xxxx::xxx > fe80::xxxx:xxxx:xxx:bf4: [icmp6 sum ok] ICMP6, neighbor advertisement, length 24, tgt is fe80::xxxx:xxxx:xxx:6402, Flags [router, solicited]
09:06:49.024932 IP6 (flowlabel 0x5a86f, hlim 1, next-header UDP (17) payload length: 114) fe80::xxxx:xxxx:xxx:4775.546 > ff02::1:2.547: [bad udp cksum 0x09ee -> 0x8550!] dhcp6 solicit (xid=39ce22 (elapsed-time 3514) (option-request SIP-servers-domain SIP-servers-address DNS-server DNS-search-list SNTP-servers NTP-server AFTR-Name opt_67 opt_82 opt_83 opt_94 opt_95 opt_96 server-unicast) (client-ID hwaddr type 1 b4750ef94775) (reconfigure-accept) (Client-FQDN) (IA_NA IAID:1 T1:0 T2:0) (IA_PD IAID:1 T1:0 T2:0))
09:06:54.586189 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) 2401:xxxx:xxxx::xxx > fe80::xxxx:xxxx:xxx:bf4: [icmp6 sum ok] ICMP6, neighbor advertisement, length 24, tgt is fe80::xxxx:xxxx:xxx:6402, Flags [router, solicited]
09:06:55.311421 IP6 (class 0xc0, hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::xxxx:xxxx:xxx:6402 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 24
        hop limit 64, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 0s, retrans time 0s
          source link-address option (1), length 8 (1): c0:xx:xx:xx:xx:02
            0x0000:  c0xx xxxx xx02
^C
18 packets captured
18 packets received by filter
0 packets dropped by kernel

root@OpenWrt:~# ifdown wan6
root@OpenWrt:~# ifstatus wan6
{
        "up": false,
        "pending": false,
        "available": true,
        "autostart": false,
        "dynamic": false,
        "proto": "dhcpv6",
        "device": "eth1.2",
        "data": {

        }
}
root@OpenWrt:~# ifup wan6
root@OpenWrt:~# ifstatus wan6
{
        "up": false,
        "pending": true,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "proto": "dhcpv6",
        "device": "eth1.2",
        "data": {

        }
}

The above is for DHCPv6 protocol.

If I change the protocol from DHCPv6 to unmanaged, then when I do ifup/down wan6, the up/down state will change accordingly.

[chuacw]

Thanks for all the help!

This appeared to be an issue on the ISP's end.

I now have IPv6 again (but currently on LEDE 17.01.4, will switch to 18.06.4 later today)