Comments on: WTFriday: http://2915189091

By: Lars

Lars — Fri, 12 Oct 2012 18:23:14 +0000

Interesting stuff!

It is really a matter of how the IP address is parsed, rather than how it is stored, as the two are in independent.

This answer gives documentation on how such IP addresses are parsed in iputils such as (certain versions of) ping:

By: Tom Wijsman

Tom Wijsman — Sat, 11 Feb 2012 11:04:48 +0000

As a not native English speaker, I have never seen this in school. Probably not the first time that someone mentioned me, but I'll correct it... :)

By: naught101

naught101 — Sat, 11 Feb 2012 07:02:50 +0000

@Tom: Now your first sentence doesn't make any sense, grammatically :P I would suggest "While this does not always work in every browser (eg. some versions of Firefox), it does work in most browsers ..."

By: Josh

Josh — Sat, 11 Feb 2012 05:56:25 +0000

” to type an URL.” The use of ‘an’ would indicate that you pronounce ‘URL’ like ‘earl’. This is not common, and I have heard it mocked in the same vein as “CSI: Miami”‘s pronunciation of ‘GUI’ as ‘gooey’. Indeed, it seems to me as strange as pronouncing ‘CSI’ as ‘see’.

Actually when I first read it, I thought you had simply used ‘an’ by accident and meant to say “a URL” (as in “a you-are-el”)

By: grawity

grawity — Fri, 10 Feb 2012 23:53:13 +0000

As far as I know, these kinds of addresses are supported internally by the system – the program never needs to convert them to binary manually; it simply gives the “host” part to getaddrinfo() and the system translates it. Both winsock on Windows and glibc on Linux support addresses of less than four components.

Ah, I almost forgot. They also support two or three components, as well as hex and octal. Try http://0321.0×55.58711/ for Google. Have fun.

Addition: In particular, to shorten an address you can use “d” (as in the original post), “a.d” and “a.b.d” in addition to the typical “a.b.c.d”.

There are cases where it’s handy to omit a few components. For example, when dealing with addresses in 10/8, you can just say “10.42” to mean “10.0.0.42”… or you can say “10.259” to mean “10.0.1.3”; here components larger than 255 are valid, they simply overflow to the adjacent component.

By: Tom Wijsman

Tom Wijsman — Fri, 10 Feb 2012 20:34:48 +0000

Could depend on version or proxy settings, I haven't researched how the different browsers resolve this. One could deep-dive into the Firefox to figure this out but it's kind of out of the scope of Super User, thanks for mentioning that it does seem to work in some versions. I've slightly changed the sentence in the blog post...

By: Nate Koppenhaver

Nate Koppenhaver — Fri, 10 Feb 2012 20:09:09 +0000

The http://2915189091/ link works in Firefox 10 (on WinXP) – it goes to Google