> A popular implementation of IP networking, originating in 4.2BSD, contains a function inet_aton() for converting IP addresses in character string representation to internal binary storage. In addition to the basic four-decimals format and 32-bit numbers, it also supported intermediate syntax forms of octet.24bits (e.g. 10.1234567; for Class A addresses) and octet.octet.16bits (e.g. 172.16.12345; for Class B addresses). It also allowed the numbers to be written in hexadecimal and octal representations, by prefixing them with 0x and 0, respectively. These features continue to be supported in some software, even though they are considered as non-standard.
(https://en.wikipedia.org/wiki/Dot-decimal_notation#IPv4_addr...)
Never use this.
x -> 0.0.0.x
x.y -> x.0.0.y
x.y.z -> x.y.0.zI was also coming back in to edit my comment and write that my x -> 0.0.0.x was technically wrong and the same for the others. If you stick to only single-byte values then what I wrote was correct but if the values span multiple bytes they fill in the missing 0s appropriately, as in:
256 -> 0.0.1.0
1.256 -> 1.0.1.0 x -> x3.x2.x1.x0
x.y -> x.y2.y1.y0
x.y.z -> x. y.z1.z0
x.y.z.w -> x. y. z. w
The "zeros" happen when the last number is smaller than 256 (or 65536, etc.), but it doesn't have to be. For example 10.258 is a valid way to write an IPv4 address, it's the same as 10.0.1.2.
10.0.0.3 -> ping 10.3
If you are talking about the short url, well ipv4 allows it and they needed to save space to fit on the floppy ;)