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by AmericanChopper 2071 days ago
I’ve been assigned a .0 public IPv4 address by AWS before. I was a bit confused when I first saw it, but it worked just fine.
3 comments

Sure, there is no problem with using a .0. For example in 10.0.0.0/23 you'd have

10.0.1.0/32

As a perfectly valid IP address.

Also, routing an entire block allows you to use all of the IP's in said block. So there are ways to do it efficiently, but with routing a block that block is not considered on-network and thus doesn't have a broadcast address nor can it use one.

I had this too. I assumed it would be fine - and it mostly was. However, we tracked a weird bug with some of the companies IoT products not being able to open a connection to the .0. Never figured out if this was a dodgy IP stack on the devices, or if it was the particular mobile carrier in that area of the world. My money would be on the latter though.
Yep, you can run into weird issues at times with devices/firewalls that are misconfigured. Saw more than 1 admin that would drop anything from a .0 as "it is a bad address and nothing from that address should cross a router".
That works when the subnet is /23 or larger.