PREFIX in sample ifconfig.eth0/ipv4 file

Jeremy Huntwork jhuntwork at
Thu Aug 5 19:04:15 PDT 2004

On Thu, 2004-08-05 at 18:09 -0700, Kevin P. Fleming wrote:
> I'm not opposed to this explanation (although I prefer Archaic's), 
> except for one thing: we should _not_ perpetuate the "class C" concept. 
> Classful routing is gone, dead, over, done with, pining for the fjords.

Thanks for pointing this out, I was unaware. I'd be surprised if I was
the only one, there's a lot of sources out there that still teach
network classes.

> Anyone learning about these concepts today should not even be concerned 
> with class-based routing at all, they should only learn CIDR, VLSM 
> (variable length subnet mask) and the use of prefixes. None of those are 
> topics for the LFS book, though, of course.

Here's an article I came across about it.

In any case the old "class C" mask is what is often being used which is
why the default of 24 is chosen ;)  But you're right, it's wise to call
it the right thing.

I also liked Archaic's description, but I thought an explanation that
showed the binary would make it easy to grasp at once.

Jeremy Huntwork

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