IPv6 gateway outside of the subnet.

[Krakox44]

Hi guys, I'm trying to assign a /64 subnet for each VM that I create from a bigger /44, the issue is that the gateway I have is on a different block, how can I solve this?

Is link-local something viable?

 

[Hannes Laimer]

Yes,

you can use the link-local address of the gateway as the default GW for the host, this is common practice. VMs then have the hosts Global Unicast Address as their gateway. Just make sure ipv6 forwarding is enabled on the host.

# add this to /etc/sysctl.conf
net.ipv6.conf.all.forwarding=1

# then
sysctl -p

So on the host you have

ip -6 route add default via fe80::external_gateway_ll%<IFACE>

and in the VMs it would look something like

ip -6 addr add 2001:db8:1::1/64 dev <VM_IFACE>

2001:db8:1::1 is a placeholder for whatever the Global Unicast Address of the PVE host is.

you can get the your GUA address of the host with

ip -6 addr show dev <IFACE>