I continue in my constant learning with Arch Linux and this type of post will serve as a Memorandum in the future. In this case one of my doubts was how to activate Hi en Pidgin to use local messaging, machine to machine, without a server in between, as it is necessary for my day-to-day work.
The thing is simple. We only have to install two packages:
# pacman -S avahi nss-mdns
And then activate the service:
# systemctl enable avahi-daemon.service
And that's it…