From: Simon Lodal <simonl@parknet.dk>
To: Ben Efros <ben@xgendev.com>
Cc: netfilter-devel@lists.netfilter.org
Subject: Re: RFC: Partial IP4 syntax
Date: Wed, 29 Sep 2004 07:42:38 +0200 [thread overview]
Message-ID: <415A4B4E.1080801@parknet.dk> (raw)
In-Reply-To: <415A3263.7080708@xgendev.com>
What tools are passing IP's literally as full 32bits? I understand why
programs (especially in script languages) might do it internally, but
between programs?
Funny, works with ping, but not ssh. Works with iptables for --src and
--dst (surprise). But not for SNAT --to-source.
Just looked at RFC 1123, it only talks about dotted decimal
representation. The 32bit form is not even documented anywhere afaik,
and honestly I do not remember seeing it.
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.
Simon
>> Iknow IP address syntax should not change every day. But this will not
>> break or exclude old syntax. I do not see it clashing with
>> other/future syntax.
>
>
> Wrong. IP numbers can also be written in 32-bit unsigned notation. In
> your first example:
> 10 being 10.0.0.0/8
> 10 is actually treated as unsigned 32bit int, meaning you're address is
> actually 0.0.0.10
> Try this command and see for yourself:
> "ping 5000"
> Notice how ping is actually sending to "0.0.19.136" ?
>
> This is done because 32-bit addresses should be representable as a 32bit
> number and not just as a string representation of the address for a
> variety of reasons.
>
> Unfortunately your idea would break a LOT of very useful tools and ways
> of representing valid ip numbers.
>
> Ben
next prev parent reply other threads:[~2004-09-29 5:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-29 1:41 RFC: Partial IP4 syntax Simon Lodal
2004-09-29 3:56 ` Ben Efros
2004-09-29 5:42 ` Simon Lodal [this message]
2004-09-29 8:55 ` Henrik Nordstrom
2004-09-29 16:38 ` Simon Lodal
2004-09-29 17:05 ` Henrik Nordstrom
2004-09-29 18:45 ` Simon Lodal
2004-09-29 19:11 ` Cedric Blancher
2004-09-29 22:41 ` Simon Lodal
2004-09-29 19:39 ` Henrik Nordstrom
2004-09-29 8:50 ` Henrik Nordstrom
2004-09-29 16:37 ` Simon Lodal
2004-09-29 16:54 ` Henrik Nordstrom
2004-09-29 18:21 ` Simon Lodal
2004-09-29 19:30 ` Henrik Nordstrom
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