Does it make sense to manually specify broadcast for interfaces?

Question

linux

I decided to stop using net-tools and iproute2 at the same time and moved my scripts from
ifconfig eth0 192.168.2.1 netmask 255.255.255.0to

ip link set eth0 up
ip addr add 192.168.2.1/24 dev eth0

But upon careful comparison of the result, it turned out that the second option does not set broadcast.
It was:

1: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP 
    link/ether 1c:6f:65:c5:d6:d7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 brd 192.168.2.255 scope global eth0

became:

1: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP 
    link/ether 1c:6f:65:c5:d6:d7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 scope global eth0

Of course, I can add it with pens to ip addr, but the question arose: is it even necessary? And if so, to whom and for what? Moreover, it seems to have prescribed routing like this:

# ip route show table local dev eth0 scope link
broadcast 192.168.2.0  proto kernel  src 192.168.2.1 
broadcast 192.168.2.255  proto kernel  src 192.168.2.1

Answer 1

There is not much difference, the main thing is that broadcast routes are present in the local table. But here you need to look at the situation: I saw examples of dhcp server autoconfiguration scripts that dropped it (dhcp server) without a broadcast address on the interface.
You can also use a structure like this:

ip addr add 192.168.2.1/24 brd + dev eth0

In this case, the broadcast address will be calculated automatically.