4 ms·

I suspect it gets mapped to 1.0.0.1 because no other resolution is possible. Any other locations for the two zeros results in an invalid IP (either starting or

I suspect it gets mapped to 1.0.0.1 because no other resolution is possible. Any other locations for the two zeros results in an invalid IP (either starting or ending in 0).

jodrellblank 4y ago
Ending in 0 is valid; you can have 1.0.1.0/23 as an IP. https://stackoverflow.com/a/14915309/ https://stackoverflow.com/a/14915309/ https://jodies.de/ipcalc?host=1.0.1.0&mask1=23&mask2= https://jodies.de/ipcalc?host=1.0.1.0&mask1=23&mask2=
simonjgreen 4y ago
Absolutely nothing wrong with ending with a .0. I suspect you are confused by n.n.n.0/24 being a network address in a /24 network which is obviously very common. However there are way more networks of other sizes that have .0 addresses in them.
- WarOnPrivacy 4y ago
  I once had my ISP (BHN) assign me a public IP that ended in .0 That turned out to be a neat experiment. I regularly hit webpages and other services that would deny my connection. I guess they considered me multicast traffic or some sort of bogon.
  - deleted 4y ago
    [deleted]
- schoen 4y ago
  We're also arguing that it ought to become usable even in a /24: https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-lowest-address/ https://datatracker.ietf.org/doc/draft-schoen-intarea-unicas... It only requires changes within the LAN to accomplish this, since distant hosts are already not supposed to assume anything about how networks are or are not subnetted. (For instance, they don't know whether you're on a /24 or not.) You can find some addresses ending a lot of zeroes that already work within http://ec2-reachability.amazonaws.com/ http://ec2-reachability.amazonaws.com/
  - preisschild 4y ago
    I still don't understand why, instead of doing something like this, not just switch to IPv6.
    - schoen 4y ago
      If you're operating a public site and you switch to IPv6-only, you'll no longer be reachable by the majority of the current Internet. That's a pretty big sacrifice for most people. If you're operating a public site and you don't switch to IPv6-only, for example by doing dual-stack, you'll still need IPv4 addresses. The challenge is that "just switch to IPv6" isn't something that you can do unilaterally if you need to talk to the rest of the Internet.
- profile53 4y ago
  Huh, and today I learned something new. Thanks!

I suspect it gets mapped to 1.0.0.1 because no other resolution is possible. Any other locations for the two zeros results in an invalid IP (either starting or ending in 0).

jodrellblank 4y ago

Ending in 0 is valid; you can have 1.0.1.0/23 as an IP. https://stackoverflow.com/a/14915309/ https://stackoverflow.com/a/14915309/ https://jodies.de/ipcalc?host=1.0.1.0&mask1=23&mask2= https://jodies.de/ipcalc?host=1.0.1.0&mask1=23&mask2=

simonjgreen 4y ago

Absolutely nothing wrong with ending with a .0. I suspect you are confused by n.n.n.0/24 being a network address in a /24 network which is obviously very common. However there are way more networks of other sizes that have .0 addresses in them.

WarOnPrivacy 4y ago
I once had my ISP (BHN) assign me a public IP that ended in .0 That turned out to be a neat experiment. I regularly hit webpages and other services that would deny my connection. I guess they considered me multicast traffic or some sort of bogon.
- deleted 4y ago
  [deleted]
schoen 4y ago
We're also arguing that it ought to become usable even in a /24: https://datatracker.ietf.org/doc/draft-schoen-intarea-unicast-lowest-address/ https://datatracker.ietf.org/doc/draft-schoen-intarea-unicas... It only requires changes within the LAN to accomplish this, since distant hosts are already not supposed to assume anything about how networks are or are not subnetted. (For instance, they don't know whether you're on a /24 or not.) You can find some addresses ending a lot of zeroes that already work within http://ec2-reachability.amazonaws.com/ http://ec2-reachability.amazonaws.com/
- preisschild 4y ago
  I still don't understand why, instead of doing something like this, not just switch to IPv6.
  - schoen 4y ago
    If you're operating a public site and you switch to IPv6-only, you'll no longer be reachable by the majority of the current Internet. That's a pretty big sacrifice for most people. If you're operating a public site and you don't switch to IPv6-only, for example by doing dual-stack, you'll still need IPv4 addresses. The challenge is that "just switch to IPv6" isn't something that you can do unilaterally if you need to talk to the rest of the Internet.
profile53 4y ago
Huh, and today I learned something new. Thanks!