Private use of non-RFC1918 IP space

Jeroen Massar jeroen at
Mon Feb 2 16:07:50 UTC 2009

Trey Darley wrote:
> Hi, y'all -
> Some colleagues and I are running into a bit of a problem. We've been
> using RFC 1918 Class A space but due to the way subnets have been
> allocated we are pondering the use of public IP space. As the network in
> question is strictly closed I don't anticipate any problems with this as
> the addresses would be unambiguous within our environment. I'm curious if
> anyone else is doing this.

Of course you can use public address space, and actually you should have
been doing that already for years.

The catch is of course that you just get it from your local RIR or LIR,
thus making sure it is globally unique, as that is where the problem of
RFC1918 lies for most people.

Another trick is of course to start moving to IPv6: get a /48 or more
from your local LIR/RIR and you have all the IPs you will ever need
(unless you plan wrong and ask for too little ;)


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 187 bytes
Desc: OpenPGP digital signature
URL: <>

More information about the NANOG mailing list