On Thu, Jun 19, 2003 at 07:49:14AM -0400, J. Noel Chiappa wrote:
My take is that NAT's respond to several flaws in the IPv4 architecture:
- 1) Not enough addresses - this being the one that brought them into
existence.
- 1a) Local allocation of addresses - a variant of the preceeding one, but
subtly different; NAT's do allow you to allocate more addresses
locally without going back to a central number allocation authority,
which is very convenient.
- 2) Easy renumbering when switching ISP's - a benefit that only was realized
later in time, but a significant one all the same - especially for
those people who reckon that switching addresses is a really painful
undertaking.
I have to agree with Noel here. As much as I hate NAT's because they
screw up various protocols --- not the least of which are Kerberos,
Zephyr, AFS, etc. --- I am running a NAT at home precisely because it
solves the above issues.
Unfortunately, it hasn't been clear to me IPv6 necessarily solves
these problems. If it's true that some address registries have been
handing out IPv6 addrs. with the same parsimony that they've been
handing IPv4 address, and that routing concerns means that we won't
have provider independent addressing, and various application writers
are using promoting the use of explicit IPv6 addresses in
configuration files, license managers, etc., then we may end up with
NAT's even in IPv6 land. And that would be most unfortunate.
- Ted