CIDR - networking

[Andrew Hammond]

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On 8-Jan-06, at 23:37, Kihara Muriithi wrote:

>> Then again, given the scarcity of non-CIDR systems these days, why  
>> are
>> you so concerned with it?  In the 12 years I've been working with IP,
>> I've never seen anything but CIDR.  Address classes have been  
>> obsolete
>> for years.
>>
>   That sentence has homed at the problem. Its that I can't tell how a
> class address look like. My understanding was that, if you see a
> netmask like 255.0.0.0 or 255.255.0.0 on what they were calling A and
> B respectively, then that is class system. That is how my box is
> currently set up. ie 192.168.1.3  255.255.255.0
>   I thought CIRD carry a mask like 255.128.0.0? ie no clean 255 to 0
> transition. How would I identify a non-CIDR if I see one? I am very
> sorry for my ignorance by the way
>
> William


Class based networks have implicit netmasks based on the IP. Anywhere  
you see an explicit netmask, you have CIDR.

For example, 10.0.0.0 is a class based network. 10.0.0.0/8 is the  
same network but with CIDR notation.

You can find the breakdown of classes and netmasks in the RFC.

http://rfc.net/rfc791.html#p24

__________________________________________________
Andrew Hammond    416-673-4138    ahammond-swQf4SbcV9C7WVzo/KQ3Mw at public.gmane.org
Data Services Group Manager, Afilias Canada Corp. Ltd.
CB83 2838 4B67 D40F D086 3568 81FC E7E5 27AF 4A9A


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