IPv6 stability on dedicated servers with and without virtualisation


Hi, there,

I’m experiencing somehow random issues with ipv6 on the online infrastucture.
I have followed this documentation : https://documentation.online.net/en/dedicated-server/network/ipv6/prefix

and I am using ipv6 connectivity on debian 7/8 and 9 VMs and servers in two different Onlinet.net datacenters.
Follwing the dhclient+DUUID+/64 prefix I choose to only have one IPv6 configured like this :

iface enp0s3 inet6 static
address 2001:bc8:37ca:301::1
netmask 64
accept_ra 1
pre-up sleep 3 ; dhclient -nw -cf /etc/dhcp/dhclient6.conf -pf /run/dhclient6.enp0s3.pid -6 -P enp0s3

So, unless you see something cleary odd, this setup seams to work fine… for sometimes.
That is : I have ipv6 connectivity as expected and across reboots. And then after some random time from 1 month to sometimes 6 months it stops all together.
No clear problem logged on my side, dhcp client still running, “ip addr” still show IPv6 but no routing of packets take places.
This type of problem also manifest in case of VM moving across servers, which lead me to think about something related to leases not renewed o dhcp communication problems.
A manual dhcp client restart on VM side + wainting a few hours will solve the problem but that clearly indicate a problem somewhere.

So, before digging on my own, has anyone here a truly (I mean at least one year) functional setup of ipv6 connectivity on a server and a VM, or have other run into the same issue ?