Large ISPs doing NAT?

Tue Apr 30 18:17:15 UTC 2002

> -----Original Message-----
> From: Tony Rall [mailto:trall at almaden.ibm.com] 
> Sent: 30. apríla 2002 19:59
> To: nanog at merit.edu
> Subject: Re: Large ISPs doing NAT?
> 
> 
> 
> 
> 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.

well.. yes and no.
depends on definition and how you set the services. i don't know how you treat this in u.s. but in europe gprs is mostly considered being a value-added service to gsm instead of a real internet connectivity replacement.

if you think of gprs a bit it will never have enough capabilities to serve as a full-time inet service. it's a great solution for accessing your data remotely but it's very limited in means of capacity

and then you have those 'pdp-contexts' or how they call it. it's just another acronym for a vpn... if a corporate user requires full ip connectivity then why not give him a vpn uplink directly to their hq and the users can safely use private addresses according to corporate policy. in this way gprs is very similar to mpls. i have worked on gprs-mpls vpn integration and it works just fine.

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

you also may give the [common] user an opportunity to have 'limited' service set (so you can use private addresses + nat/pat) for lower price or pay a bit more for 'full' service. i think the 'limited' in real life can safely cover requirements of 95% of the customers. do you think they will download mp3's and avi's via gprs? how? :)) from my point of view if you cover http, e-mail and various similar services you will provide most user with more than they ever would expect, wouldn't you?

> 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
> 
> 

deejay

--

Tomas Daniska
systems engineer
Tronet Computer Networks
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