Re: CIDR prefixes

["Brett D. Watson" <[e-mail]>]

  a very useful tool is on the net somewhere (can't remember where 
but i think tony bates was involved in writing it, at least i think 
it come from ripe while he was there) called "aggis".  it will accept 
various inputs like:

genbsd:~ $ aggis 204.74.64.0/18

  204.74.64/18 is an aggregate equivalent to 64 Class Cs:  204.74.64
                                                       to  204.74.127


or:

genbsd:~ $ aggis -d 204.74.64.0/18

  204.74.64/18(255.255.192) is an aggregate equivalent to 64 Class 
Cs:  204.74.64 to  204.74.127



or even:

genbsd:~ $ aggis
usage:  aggis [-flags] ip_prefix[/prefix_length]        (Version 2.7)
   or:  aggis [-flags] aggregate #_of_nets
   or:  aggis [-flags] aggregate - aggregate
             e.g.  aggis 141.212 - 141.214 
   or:  aggis [-flags] aggregate - <end_last_byte_value>
             e.g.  aggis 141.212/18 - 216 

           flag -d: "include dotted decimal masks"
           flag -D: "include inverted dotted decimal masks"
           flag -r: always use "host ranges" for expansions.
           flag -q: always use "dotted.quad" format
           flag -l: expand into a list of classful ip/lens
           flag -L: expand into a list of classful ip's only
           flag -T: trim extra blank lines on expansions
           flag -h: print this "help".



  *very* handy tool.

-brett

> >
> Rick,
> 
> You can find the information you're looking for in RFC 1878.
> 
> Regards,
> 
> Kim Hubbard
> InterNIC IP Registry
>  
> > To CIDR:
> > 
> > Has anyone taken the CIDR prefix table, and converted it to the appropriate
> > subnet mask?
> > 
> > I'm having a devil of a time with this, and it would sure be nice if there
> > was a table (such as the Class C Subnetting sheet that I have) that would
> > look something like this:
> > 
> > CIDR Prefix     # of former class C nets        Appropriate Subnet Mask 
> > /24                     1                       255.255.255.0
> > etc., etc.
> > 
> > This would sure make it easy for a dummy like me to set up routers that are
> > using the CIDR scheme, as I am only clear on the old Subnet Mask way of
> > doing things.
> > 
> > Anyway, if there is such an animal, I would appreciate knowing where to get
> > it.  Otherwise, I guess I'll have to sit down and wrestle with creating this
> > list myself.
> > 
> > Thank you for your time.
> > 
> > Rick Ervin
> > DNA
> > 
> > 
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>