My router is RB2011 with ROS 7.6.

And I want to enable ipv6 on it, after search the internet, I do things below:

1.enable ipv6 as setting.jpg

2.define ipv6 DHCP client as dhcp client.jpg

3.define ipv6 address as address.jpg

4.define ipv6 nd as nd.jpg

After that, I can see the ipv6 address-list as address-list.jpg, but my PC connect to rb2011 without ipv6 ip address.

Then search the internet again, somebody said need disable IGMP snooping in bridge-local that I defined in address.jpg, I do it, and the ipv 6 address showed additional entry on it, and my pc will has the ipv6 ip address. see address-list-2.jpg.

But after I power off the RB2011 and power on again, the address-list-2.jpg will change back to address-list.jpg, the additional entry was gone, and the pc without ipv6 ip again!

Any suggestion about it?

Random blogs and videos on the Internet are often incomplete, less than optimal, or just wrong. 'Managed Address Configuration' is incorrect, it should only be enabled if you have a DHCPv6 server. 'Add Default Route' is incorrect but sometimes works, using Router Advertisments is the correct method.

Screenshots do not show everything, post the output of /export or /ipv6 export at a minimum after redacting serial number, any public IP addresses, etc.

Thanks. Here is the /ipv6 export

[admin@MikroTik] /ipv6> export
# jan/14/2023 11:54:53 by RouterOS 7.7
# software id = C50F-KI26
#
# model = RB2011UiAS-2HnD
# serial number = ---------------
/ipv6 dhcp-server
add address-pool=ipv6pool disabled=yes interface=bridge-local name=DHCPv6
/ipv6 dhcp-server option sets
add name=DHCPV6
/ipv6 address
add address=::4e5e:------- eui-64=yes from-pool=ipv6pool interface=bridge-local
/ipv6 dhcp-client
add interface=PPPoE-WAN-1 pool-name=ipv6pool request=prefix use-peer-dns=no
/ipv6 firewall filter
add action=accept chain=input comment="Accept DHCPv6-Client prefix delegation" dst-port=546 protocol=udp src-address=fe80::/16
/ipv6 nd
set [ find default=yes ] disabled=yes hop-limit=64 mtu=1496 ra-interval=20s-1m
add hop-limit=64 interface=bridge-local mtu=1496 ra-interval=20s-1m
/ipv6 settings
set max-neighbor-entries=8192
[admin@MikroTik] /ipv6>

Firstly for the Mikrotik to pick up the default route you need
/ipv6 settings
set accept-router-advertisements=yes

Note the learnt default route does not appear in the IPv6 routing table.

I'm not sure why you have non-default ND parameters, perhaps from earlier versions. The current defaults for those are hop-limit=unspecified mtu=unspecified ra-interval=3m20s-10m

The DHCP server and options / option sets are not required unless you wish client devices to request non-address information such as DNS servers, etc. This is done when ND other-configuration=yes

Other than that there isn't anything obvious. Looking back at the images the address which disappears is the link-local address, I suspect it is a display artefact which incorrectly hides them when another dynamic address exists.