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Comment by vesche | Hacker News Reader

This would be really neat. However, it might confuse or complicate some tools output (like netstat) that use the standard 0.0.0.0:80 style listening notation. That is if 0.0.0.0 becomes a valid address.

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It excludes 0.0.0.0/32, which is what “0.0.0.0” is when shown as a bare IP, so that will only be a complication if some tools (surely some do) assume that 0.0.0.0/32 is equal to anything in range 0.0.0.0/8.

No, 0.0.0.0 will still be reserved.

>0.0.0.0/32 is still prohibited, of course.

Gotcha! I skimmed too fast. I'm all for it then.

From the commit message:

> 0.0.0.0/32 is still prohibited, of course.

The \*.0/32 is always excluded from usable address range anyway.

Are you saying a valid IPv4 address can not have a value of 0 in the 4th octet? That is not true at all.

It's a valid IP address, but it's the 'network address'. 'usable' range is 1-254. That's my understanding anyway?

That's not correct. Not every subnet is a /24. Further, you don't necessarily need a network and broadcast address for a subnet. That's a local issue. See IETF RFC 3021 for one example of not having a network and broadcast address.

it's the network address only if you define your network as a /24 . if the mask is different it could be a completely valid address.

:facepalm: right, of course, makes sense. Thanks.

0.0.0.0 is a "network" address no matter how many bits are in the netmask. Having said that, there really isn't a use of "network" addresses (especially as distinct from broadcast), apart from the convention being baked into basically everything.

Or anything smaller than a /24.

Zero in the last octet is problematic if you want to be generally reachable on the internet. We used x.y.z.0 as a vip at fb for a while, but learned the hard way that some people can't reach those ips.

Some additional info from RIPE: https://labs.ripe.net/Members/stephane_bortzmeyer/all-ip-add...

It's amazing how many stupid assumptions on the part of some people create these extraordinarily difficult situations to navigate.

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