Re: RFC: Partial IP4 syntax

[Simon Lodal <simonl@parknet.dk>]

Henrik Nordstrom skrev:
> IETF has not defined such ascii representation of IPv4 addresses, but 
> the BSD libc inet_aton function does and this has been inherited by very 
> many systems and tools.
> 
> This notation is being depreated as it does not serve a very useful 
> purpose and can be somewhat confusing, but it exists and conflicting 
> with it would be a bad idea.
Ok, let's see where we may get compatibility problems:
1) iptables input: iptables' support for full 32bit format addresses is 
both lacking and undocumented and could disappear without notice. So if 
any programs use it they should rather be fixed.
2) iptables output: There is a potential problem here, if programs parse 
iptables or iptables-save output, and they know about the full 32bit form.

iptables -L is for human eyes while iptables-save is for machine 
parsing. So what if we make iptables -L print in any format it likes 
(not intended for machine parsing anyway), but have iptables-save always 
print addresses in full dotted quad?

>> If it is really a problem I agree my scheme will break it. Could 
>> probably be solved by changing the default to incomplete-at-beginning, 
>> so 10 = .10 = 0.0.0.10.
> 
> 
> Not without breaking existing "industry standards" on how IP numbers can 
> be typed.
Why? I certainly do not want to break anything, formalized or not, only 
extend.

> You could use 10. for the 10.0.0.0/8 network.
That is what I propose.

The question is how to interpret a single number. Implicitly append or 
prepend a dot? Or interpret as full 32bit notation? Or ignore it?


Simon