The first IP address of an IP subnet is the network address, which stands for the whole network, while the last address is the broadcast address.

As far as I understand, we never really send packets to the network address, it's purely symbolic, for use in firewall rules etc., to mean the whole IP range of the network.

Is this correct, or does it sometimes happen that an actual IP packet has a network address (first address of the subnet) as its source or destination IP address?

  • Sadly, questions about historical trivia are off topic here. There are several books and other material available that go into these kinds of decisions. Remember that networking technologies developed in several stages with many iterations over time.
    – Ron Trunk
    Apr 4 '20 at 13:14
  • Okay, removed all historic aspects.
    – isarandi
    Apr 4 '20 at 13:15
  • 1
    Not that I'm aware of. It easy to look backward and say there's a better way to get to where we are today, but at the time, it wasn't clear where all this new-fangled packet switched networking was headed.
    – Ron Trunk
    Apr 4 '20 at 13:19
  • This answer explains about /31 networks that use both the network and broadcast address.
    – Ron Maupin
    Apr 4 '20 at 13:45