Re: RFC: Partial IP4 syntax

[Simon Lodal <simonl@parknet.dk>]

Henrik Nordstrom skrev:
> On Wed, 29 Sep 2004, Simon Lodal wrote:
> 
>> When people talk about the 10.44 network, I assume they append .0.0, 
>> not insert them in the middle. My proposal does that with a double 
>> dot, eg. 10..44 = 10.0.0.44.
> 
> There is a well established meaning in the computing industry of 10.44 
> to mean 10.0.0.44, not 10.44.0.0.

Really?


> There is also a well established meaning in the routing business of 
> 10.44/24 to mean 10.44.0.0/24, but then only in CIDR notation with a 
> mask size (not netmask), and certainly not without the mask size.
> 
> There is no one using double dots that I know of.

Just why I think we can use it (same goes for leading and trailing dots).

The double dot is similar to double colon in ipv6, so it's meaning 
should not be surprising.


> Guessing the netmask size is generally bad and should be avoided imho. 
> Lots of problems have been caused by computers guessing netmasks based 
> on zeroes..

Agree, but I calculate netmask based on *missing* octets. Different.


>>> 10.59470 is the same as 10.0.232.78
>>>
>>> 2888886350 is the same as 172.48.232.78
>>
>> I understand if that is being deprecated.
>>
>> They could at least have used hex!
(should never have said that :) (what about binary and octal?)
> 
> 
> Many allows hex notation using 0xXX syntax per element in the IP address..
> 
> 0x54.0x63.0xFE.0xEE
> 0x5463FEEE
> 0x54.0x63FEEE
> 84.6553326
> 84.99.254.238
> 84.99.13094
> 
> is all the same IP address. You can try it with ping if in doubt.

Ok but hey is ping just a testbed for strange notations? What other 
programs (and users) actually accept all these notations? And I am 
talking real world use on Linux (as long as iptables is not ported to bsd).

iptables has never accepted all these syntax variants, or even 
documented that a few of them might work. So what do we lose by still 
not doing it?

Anyway nothing I propose would break any of these.


>> What I also want is a way to only specify the least significant bits. 
>> If I do not care about the first octet (10), the above would just 
>> become ".1".
> 
> Which with the already established notation is simply 1/0.255.255.255 
> which matches *.0.0.1
strlen(".1") = 2
strlen("1/0.0.0.255") = 11

That's why.


Simon