NDP table not updated after OPNsense restart

[Cristian_Ichim]

Hello everyone,

I've noticed an issue where after restarting my OPNsense edge router, its NDP table (and occasionally the ARP table) does not update properly. Specifically, some devices connected to OPNsense are missing from the NDP table entirely after a reboot.

When I run ndp -a on OPNsense after a reboot, certain devices do not appear in the list at all—meaning OPNsense fails to map their MAC addresses to their IPv6 addresses. As a result, it seems like OPNsense is unaware of their existence in terms of IPv6 connectivity.

This issue is most persistent when OPNsense interacts with a Proxmox Server and its VMs. Occasionally, it affects Android phones, but to a lesser extent. In some cases, Proxmox itself disappears from the ARP table, losing its IPv4 address.

The only way I can get OPNsense to recognize these devices again is by completely restarting the Proxmox server along with all its VMs.

Has anyone encountered this issue before? Is there a way to force OPNsense to update its NDP table correctly after a reboot without restarting all affected devices?

Thanks in advance for any insights!