On 2020-01-31, PJ wrote:
> I have a router-to-be with 4 NICs, on which ip-forwarding is not yet
> enabled (and with OpenBSD 6.6).
>
> One IF has an IP on one network segment and the three other IFs are
> bridged together, with one of the three having an IP on another network
> segment.
>
> When I pinged the first IF, which should be alone on it's network
> segment, from a machine connected to one of the three bridged together
> IFs, I got a ping reply. I didn't expect it because forwarding is not
> enabled.
>
> What's going on here?
>
> Am I missing something?
It isn't forwarding, it's answering locally.
However this changed recently in -current:
https://marc.info/?l=openbsd-cvs=157580332113635=2
https://en.wikipedia.org/wiki/Host_model
