Bug#1067760: libc6: Curious behavior of inet_pton() on IPv4 mapped numbers

[Alessandro Vesely <vesely@tana.it>]

On Tue 26/Mar/2024 17:34:20 +0100 Bastian Blank wrote:
> On Tue, Mar 26, 2024 at 12:53:42PM +0100, Alessandro Vesely wrote:
> > I compiled the example program given in the  inet_pton(3) man page, and obtain
> > the following:
> > $ ./a.out i6 0:0:0:ffff:5.6.7.8
> > Not in presentation format
>
> This is no valid IPv6 address.


Oops, you're right.  Sorry for the confusion.


>  Where did you find that?


We were discussing a regex to catch all (valid) IP addresses when someone noted 
that leading zeroes are valid, albeit not the RFC 5952 recommended format. 
It's overly tricky for me.


Best
Ale