The latest ethernet implementation does not add a broadcast address automatically, like that doing in a stable version.
vyos@bras# set interfaces ethernet eth1 address 10.0.0.1/24 [edit] vyos@bras# commit [edit] vyos@bras# run show interfaces ethernet eth1 eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 50:00:00:02:00:01 brd ff:ff:ff:ff:ff:ff inet 10.0.0.1/24 scope global eth1 valid_lft forever preferred_lft forever inet6 fe80::5200:ff:fe02:1/64 scope link valid_lft forever preferred_lft forever ...
The topic on the forum https://forum.vyos.io/t/set-interface-ethernet-eth-broadcast-address-is-0-0-0-0/5394