4 ms·

And even though, you can still have a /24 with used .0, .255 (for example if injected via BGP on machines that have other IPs)

• candiddevmike 3y ago
  Like other things in tech, you can do this, but you really shouldn't. There are a lot of assumptions baked into those addresses per the RFCs, which are kind of like our industry's electrical code. Using a broadcast address is "not up to code".
  • NoZebra120vClip 3y ago
    Long, long ago, SunOS, and possibly other Unixes, considered x.x.x.0 as a broadcast address as well. (Or I should say more properly, an all-zeroes host address.) It took a long, long time to shake that assumption out of all code, long after the OS had stopped using .0 that way. So this is yet another domino.
  • Faaak 3y ago
    Please tell, then. But no, I don't see what is wrong with that. An outsider doesn't know the CIDR of the IP he's talking too, so it wouldn't change. It only matters for the last router in the loop, and if it's taken into account (because it's actually your infra), then it's okay
• iso1631 3y ago
  Most of my small sites are a pair of /24s, they have .255 as a loopback, split up the rest of the network into /26 or /27. Looking at the BGP table it's just two entries (one for each /24). I've encountered kit which doesn't like IPs on .0 or .255 in the middle of a /23 or larger, but I've also encountered kit which doesn't like any subnet that isn't a /24. That kit goes back to the supplier as faulty. I've never seen kit which wont sent to a random x.x.x.255 address that isn't on the local subnet