Only 5x IPv4 /8 remaining at IANA

John van Oppen jvanoppen at
Tue Oct 19 10:15:06 CDT 2010

I would say for most of our customers, especially in the hosting space, a "class C" is a /24, they just don't know networking at all and build their hosting lans using /24s for each vlan.

Very few of the requests that we get are submitted using CIDR notation.   Personally, I think this is a big reason for random table bloat, I have had so many arguments about customers being able to aggregate announcements for BGP it is not even funny...   the "I want to announce the blocks as a class Cs" request is irritatingly common.


-----Original Message-----
From: Matthew Walster [mailto:matthew at] 
Sent: Tuesday, October 19, 2010 7:53 AM
To: nanog list
Subject: Re: Only 5x IPv4 /8 remaining at IANA

On 19 October 2010 14:12,  <Valdis.Kletnieks at> wrote:
> Do you *really* want somebody working on your network that gets confused by a
> reference to 213/8 because it's in Class-C space?

I've met people who just assume anything with a 24-bit netmask is a
Class C network. For instance:

"Can I have another Class C out of 83.x please?"

No, and neither can anyone else... What's more is that they'll not use
.0, .255, .1 (because apparently only routers are supposed to use
that), .254 (who knows...)


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