[Users] [Bug 4034] URLs with square brackets are shortened

Michal Suchánek msuchanek at suse.de
Sun Jun 10 13:47:24 CEST 2018

On Sat, 09 Jun 2018 19:48:13 +0000
noreply at thewildbeast.co.uk wrote:

> https://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=4034
> Andrej Kacian <andrej at kacian.sk> changed:
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>              Status|NEW                         |RESOLVED
>          Resolution|---                         |INVALID
> --- Comment #1 from Andrej Kacian <andrej at kacian.sk> ---
> Square brackets should not be used like this in an URL. Looks like
> people at frankfurt.de should have a look at RFC 3986, where in
> section 3.2.2, it says:
>   A host identified by an Internet Protocol literal address, version 6
>   [RFC3513] or later, is distinguished by enclosing the IP literal
>   within square brackets ("[" and "]").  This is the only place where
>   square bracket characters are allowed in the URI syntax.
> https://tools.ietf.org/html/rfc3986#section-3.2.2

I suppose this came about together with IPv6 and software that predates
widespread use of IPv6 including this very bugzilla instance happily
includes the square brackets in the URL.

The basic rule of the internet protocol processing should be "Be strict
in what you send and be lenient in what you accept." Hence for
compatibility with existing systems you should accept square brackets
as part of the URL. If you want to be super correct you can encode
them in the URL you pass over to the web browser. Seems to work with
the Frankfurt site all right. 



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