openmediavault.local!!!

Hello guys. Today I realized that my server is also reachable at myservername.local. Just out curiosity, how exactly is that accomplished?
Sometime ago I tried it and failed. Then I thought it was only a matter of having avahi installed, but today I've tried it again on two raspis without success.
Is something about the domainname registration?

Thanks you guys.
I was tinking more of something running on bonjour/zeroconf/avahi protocol. The fact is that openmediavault publishes it's domain name correctly but none of the raspbian machines does. Without doing nothing I can access openmediavault.local, but not p3steel.local (my 3d printer) or domoticz.local.
I investigated that past night and came across that installing apples bonjour on a windows machine got this machine resolving the raspis. But that left behind the androids. There's nothing for them.
My main router runs DD-WRT with all it's flares and wris... but my problem is that my ISP supplies modems that are locked and can't be configured in bridge mode. All my professional and nice installation flows through and relies on a cheap device.
This morning I've done a search to all my near IPS stores and got back with 5 modems. Now I'm playing with them, It must be some valid between them.

Just wanted to know how OMV was doing it's registering so well.