Large ISPs doing NAT?

Tue Apr 30 17:59:16 UTC 2002

On Monday, 2002-04-29 at 08:43 MST, Beckmeyer <beck at pacbell.net> wrote:
> Is anybody here doing NAT for their customers?

I hope not.

If you're NATing your customers you're no longer an ISP.  You're a
sort-of-tcp-service-provider (maybe a little udp too).  NAT (PAT even more
so) breaks so many things that it would be unconscionable to advertise as
an ISP.  Even some tcp apps fail under NAT.  The NAT box may include a
number of "fix-ups" but such will never be equivalent to giving the
customer a public address.

An Internet Service Provider gives the customer a full connection to the
Internet.  All IP protocols should work.

I'm in favor of using NAT only where there is a good argument for it and
the customers are given the straight story about what they're buying and
what it won't be able to do.  Don't call yourself an ISP.

Tony Rall