getting IP v6 addresses within the LAN interface when IP V6 is set to none

[RobLatour]

In OPNSense, on my LAN interface I have:

    IPv4 Configuration Type set to Static IPv4
    IPv4 Configuration Type set to None

However, from Windows, if I ping one of my devices within the LAN from another device in the LAN using the command as follows:

ping venus.local

I get an IP v6 address.

However, if I ping the same device with

ping -4 vensu.local

I get the expected IP v4 address.

I found this out the hard way, after something broke and it took me a couple hours to find the issue was this behaviour (i.e. venus.local reporting an IPv6 address rather than an IPv4 address).

I'm not sure, but I suspect the IP v6 address is being generated from a switch within the LAN interface. 

Is there anything that can be done in OPNSense to prevent this?

(I suspect no, but thought I would ask all the same).

[Patrick M. Hausen]

Does the IPv6 address start with fe80:? If yes, that's a link local address. Devices generate these themselves. You would have to disable IPv6 *somehow* on each and every single device on your network.

It's 2024 - IPv6 is in every current desktop or server operating system and it's enabled by default. It's not going away.

[RobLatour]

yes, it starts with fe80:

[Patrick M. Hausen]

If you boot a Windows system, it's going to autoconfigure IPv6. If you boot a Mac, the same. If your PC/Mac talks to your printer via mDNS, it's most probably IPv6. There is no way back to IPv4 only.

[Monviech (Cedrik)]

That meme is amazing and Im going to steal it.

[dseven]

Further to the above; .local is the standard prefix for mDNS. OPNsense wouldn't be involved at all (assuming the two hosts are on the same subnet).

[RobLatour]

Yes, that's all pretty much the way I figured it - just thought I'd ask incase there was something OPNSense could do - but obviously not.