Final 6.2.1 update causing LAN instability/sluggishness

My meaning was not to infer issue is related to one brand of router.

For now this is information we have for those who view this thread.
Symtoms:
After upgrade to 6.2.1 and reboot
Network instability seen and some services cannot be accessed on the NAS
Can access ReadyNAS GUI but the network ports do not show on Network tab.
Can see flooding on the network. (synchronised fast blinking LED on router / switch)
May cause issue with home network not being accessible. Unpug Network cable from ReadyNAS solves home network issue

Information known so far
Issue is related to IPv6 and latest version of connman (connection manager 1.27) used by 6.x to manage all network interfaces.
This causes flooding of IPv6 information request packets.
We can reproduce with some routers and not others which are running DHCPv6.

Solutions
If not using IPv6,

unplug ReadyNAS
disable IPv6 DHCP on the router
reconnect ReadyNAS

If need IPv6,

unplug ReadyNAS,
disable IPv6 DHCP on the router reconnect ReadyNAS,
Down grade connman to 1.26 using SSH access.


apt-cache showpkg connman


check 1.26 is listed then run


sudo apt-get install connman=1.26-netgear1


enable IPv6 on router
Reboot ReadyNAS

These steps are basic listed by me from basic testing done in house there maybe other ways to achieve this.
I see other issues reported in this thread but if symptoms not like above then please start a new thread to get help from the community.

Netgear is working towards a release to solve this issue