Problem with IPv6


New Member
Mar 27, 2019
Hello, I have a problem with IPv6 communication. I have a virtual machine that uses the network / 126 its gateway is a physical server.
The problem is that when there is no IPv6 traffic and the neighbors on the gate will end up, you can not re-establish the connection.
The gate wants to re-use the information about the VM and sends a multicast packet that does not get a response.
00:25:90:93:62:50 > 33:33:ff:0f:00:27, ethertype IPv6 (0x86dd), length 86: fe80::225:90ff:fe93:6250 > ff02::1:ff0f:27: ICMP6, neighbor solicitation, who has 2a00:c020::f:27, length 32

Can anyone have an idea where to look for a problem?
Thank You in advice.
We'd need a bit more information to help you.

Please post the network config of your PVE-node, and of the virtual machine

additionally the output of
`ip addr show`
`ip route show`
from both can be helpful
For ipv6 route information you need '-6', so the command would be 'ip -6 route show'
So, on VM the operating system is MikroTik RouterOS

IPv6 configuration is:
/ipv6 address
add address=2a00:c020::f:26/126 advertise=no interface=ether1
/ipv6 route
add distance=1 gateway=2a00:c020::f:25

The network comes to the proxmox server as a tagged vlan 3799 and is added as VirtIO to vmbr0

And on proxmox server on /etc/network/interfaces interface is configured like this:
auto vmbr0
iface vmbr0 inet manual
up ip link set vmbr0 up
down ip link set vmbr0 down
bridge_ports enp4s0
bridge_stp off
bridge_fd 0
bridge_vlan_aware yes
bridge-vids 2-4094


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