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After routing a full /24 subnet to a single server it's possible to configure the server to listen to any IP from the subnet without reserving IPs for the subnet itself or for the broadcast IP.

Internally this works just great but I'm wondering if there are any problems when using the .0 IP from the internet like firewalls or routers dropping the packets? I'm taking about a single routed /24 subnet (BGP) which is not part of a larger routed subnet.

I know that when you have a /23 or larger subnet a .0 can be a regular IP (e.g. the 257th IP of that subnet), but I'm especially asking about a single routed /24, so BGP routers know that it's not part of a larger subnet. The question is if they care.

I did some tests from different ISPs and so far all packets reached the server.

meowykitten
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    Can't tell how various systems will react, but some people intend to make all those unused .0 addresses usable. See [Potential IPv4 Unicast Expansions](https://www.netdevconf.info/0x13/session.html?talk-ipv4-unicast-expansions)'s [slide (PDF)](https://www.files.netdevconf.info/f/1de5f5ffa5b64cf2b591/?dl=1). In page 15: "Zeroth address in subnet: fully usable as ordinary host". There's some history about why it couldn't before and can now. – A.B Nov 03 '19 at 11:34
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    @A.B, it says, "_Wouldn't it be a better world with a few hundred million more IPv4 addresses in it?_" That is a tiny drop in the bucket. We use already several times the possible number of IPv4 addresses because of Private addressing and NAPT. A few hundred million more addresses does nothing the alleviate the IPv4 address shortage or save us from the scourge of NAPT. – Ron Maupin Nov 03 '19 at 15:23
  • @RonMaupin I was mentionning this in relation to OP's question about x.y.z.0 (page 15), not about 0/8, 127/8 or 240/4 – A.B Nov 03 '19 at 15:49

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