[ERL] Strange ipv6 behaviour

Hi everyone,

after trying for a good month I'm finally giving up and turn to the community. I have a really stange problem with my EdgeRouter lite running EdgeOS 1.9.0. But first let me describe the setup.

I'm using the German ISP Unitymedia. They supply a cablerouter with crippled features. So I'm using an EdgeRouter lite and a Unifi AP-AC lite. The thing is Unitymedia uses DS-lite so I need ipv6 to work correctly.

I set up prefix delegation on the ERL and it works fine. All devices in the network get the correct ipv6 addresses.

No we come to the problem. The ipv6 connection on all devices doesn't work right from the start or after every reboot of the modem or the ERL. But if I SSH into the ERL ipv6 works fine. So one might think it's a firewall issue, but after waiting for some days it suddenly starts working on all devices. Strange, isn't it?

I'll post some parts of the config that might me relevant.

eth0 - the connection to the Unitymedia router

eth1 - my LAN

eth1.20 - Guest VLAN

ubnt@ubnt:~$ show interfaces
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address                        S/L  Description
---------    ----------                        ---  -----------
eth0         192.168.1.190/24                  u/u  WAN
             2a02:8070:4ab:6600:9fb2:3ff6:84bd:647c/128
eth1         192.168.0.1/24                    u/u  LAN
             2a02:8070:4ab:66f0::1/64
eth1.20      192.168.100.1/24                  u/u  Guest
             2a02:8070:4ab:66f1::1/64
eth2         192.168.2.1/24                    A/D  Local 2
lo           127.0.0.1/8                       u/u
             ::1/128

ubnt@ubnt# show interfaces ethernet eth0
 address dhcp
 description WAN
 dhcpv6-pd {
     no-dns
     pd 0 {
         interface eth1 {
             host-address ::1
             prefix-id :0
             service slaac
         }
         interface eth1.20 {
             host-address ::1
             prefix-id :1
             service slaac
         }
         prefix-length 60
     }
     rapid-commit enable
 }
 duplex auto
 firewall {
     in {
         ipv6-name WANv6_IN
     }
     local {
         ipv6-name WANv6_LOCAL
     }
 }
 speed auto

ubnt@ubnt# show interfaces ethernet eth1
 address 192.168.0.1/24
 description LAN
 duplex auto
 firewall {
     in {
         ipv6-name client6-in
     }
     local {
         ipv6-name client6-local
     }
 }
 ipv6 {
     dup-addr-detect-transmits 1
     router-advert {
         cur-hop-limit 64
         link-mtu 0
         managed-flag true
         max-interval 600
         name-server fe80::ba27:ebff:fe35:4ae6     #thats the ip of a raspberry pi for adblocking dns
         other-config-flag false
         prefix ::/64 {
             autonomous-flag true
             on-link-flag true
             valid-lifetime 2592000
         }
         reachable-time 0
         retrans-timer 0
         send-advert true
     }
 }
 speed auto
 vif 20 {
     address 192.168.100.1/24
     description Guest
     firewall {
         in {
             ipv6-name client6-in
             name GUEST_IN
         }
         local {
             ipv6-name client6-local
             name GUEST_LOCAL
         }
     }
     ipv6 {
         dup-addr-detect-transmits 1
         router-advert {
             cur-hop-limit 64
             link-mtu 0
             managed-flag true
             max-interval 600
             name-server fe80::ba27:ebff:fe35:4ae6
             other-config-flag false
             prefix ::/64 {
                 autonomous-flag true
                 on-link-flag true
                 valid-lifetime 2592000
             }
             reachable-time 0
             retrans-timer 0
             send-advert true
         }
     }
 }

ubnt@ubnt# show firewall ipv6-name WANv6_IN
 default-action drop
 description "WAN inbound traffic forwarded to LAN"
 enable-default-log
 rule 10 {
     action accept
     description "Allow established/related sessions"
     state {
         established enable
         related enable
     }
 }
 rule 20 {
     action drop
     description "Drop invalid state"
     state {
         invalid enable
     }
 }
 rule 30 {
     action accept
     description "Allow IPv6 icmp"
     protocol ipv6-icmp
 }
[edit]
ubnt@ubnt# show firewall ipv6-name WANv6_LOCAL
 default-action drop
 description "WAN inbound traffic to the router"
 enable-default-log
 rule 10 {
     action accept
     description "Allow established/related sessions"
     state {
         established enable
         related enable
     }
 }
 rule 20 {
     action drop
     description "Drop invalid state"
     state {
         invalid enable
     }
 }
 rule 30 {
     action accept
     description "Allow IPv6 icmp"
     protocol ipv6-icmp
 }
 rule 40 {
     action accept
     description "allow dhcpv6"
     destination {
         port 546
     }
     protocol udp
     source {
         port 547
     }
 }

If you need anything else, please let me know. And thanks in advance four your help!

Greetings