Re: Numbers of NAT-s in IPv4/IPv6 Network? One or more?

[Gert Doering <gert@space.net>]

Hi,

On Mon, Sep 15, 2003 at 11:33:02AM -0700, Fred Templin wrote:
> This is an interesting question, and I'm certainly no expert on
> the subject. But, in theory, couldn't there be more than one NAT
> if, e.g., the (multiple) NAT boxes communicated out-of-band
> to keep a consistent view of the aggregate state information?

It is possible, and it's actually being done in practice.  Some
firewall boxes can do this in a high-availability active/active
configuration (for example).

> (Then, you get into questions as to whether the multiple NATs
> are there for something simple like load balancing/fault tolerance,
> or for something more complex like site multi-homing.)

marketed as load balancing / fault tolerance.

Besides the case of multiple NATs working "parallel", I have also seen
cases where multiple NATs where daisy-chained (wireless network being
NATted to the fixed in-house network, which in turn was NATted to one
outside IP).  Ugly, but real.

Gert Doering
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