The Big Squeeze

Pete Kruckenberg pete at
Sun Mar 2 20:04:08 UTC 1997

> On Sun, 2 Mar 1997, Jim Jagielski wrote:
> > It's the renumbering part that I think gives people the most
> > heartburn... By the time you get "big enough" to warrent your
> > own block, you've got at least 32 ClassCs of which, I'm betting,
> > at least 28 are "given" to LAN-connected customers. This is
> > a _major_ headache not only for the ISP to go thru but also a
> > major headache to force your customers to go thru. That is, what
> > I think, is what really is most painful; that by the time you
> > are big enough to have your own block, you're too big to want
> > to renumber: Catch 22
> Yes, but as a smaller ISP you can offer much better service, and help you
> customers renumber. Yes I of all people know it is a _major_ headache, but
> it can be done, and there are ways to do it. 

I think there are some technologies available now that would drastically
reduce this headache, as well as strech out a block of assigned addresses.

For example, what about offering DHCP/BOOTP service for your customers? 
You provide a common DHCP/BOOTP server for your customers, configure their
routers to forward DHCP/BOOTP packets. It makes configuration for them a
whole lot easier and more standard (with almost every platform), plus you
can assign them a block based on what they actually need *at the moment*.
Should they need a larger block in the future, or should you renumber,
just reconfigure the DHCP/BOOTP server and their router, and you're done.

NAT is also a cool technology for this type of thing. Only assign real IP
addresses to machines that provide IP services. Put everything else on (or something else that won't conflict with real addresses).
There are few reasons (if any) why the client side of the Internet would
not work with NAT. Then, you can dynamically adjust your NAT pool of real
addresses based on how many are actually needed for real usage. Plus, a
renumber of every single client is a matter of adjusting your NAT tables,
and having them renumber whatever Web/FTP/IP-service machines they have. 

There are probably other cool ways to reduce the headache of IP
management, but these are a few I thought the group might be interested

Pete Kruckenberg
inQuo Internet Services
pete at

More information about the NANOG mailing list