IPv6 SLAAC addresses mixed up in subnets
When rebooting my pfSense, the clients on the subnets are getting SLAAC addresses from the connected and also the neighboring subnets. This phenomenon only occurs during reboot.
I have a /56 subnet from my ISP which I am splitting up in 7 subnets (/64) for my private LAN which are connected via a LAN interface with 1 untagged and 6 tagged VLANs.
All LAN interfaces are configured as DHCPv6 with router mode Managed - RA, so there shouldn't be any SLAAC, I assume.
My pfSense is running on a Hyper-V host (Windows 2016) and is connected to a Hyper-V switch internally via trunk port for the LAN. The physical NIC is a Intel X550-T2. The VLANs are configured in the pfsense setup and I had the same phenomenon when assigning multiple virtual NICs to the pfsense and tagging them in Hyper-V and attching them to the switch as Access ports instead of trunk.
I tried narrowing down the problem by disabling the offoading items under Advanced -> Networking and also experimented with different settings for the physical NIC but wasn't successful there.
Does anyone have some ideas on where to look for the configuration error?
JKnott last edited by JKnott
Any chance you have a TP-Link managed switch? Leakage between VLANs is a known problem with some models.
No, Netgear and HP. All managed.