[X4U] What is NAT and what does it mean to me?

[Robert Ameeti]

At 10:30 AM +0100, 5/11/07, David Ledger wrote:

>At 00:25 -0700 11/5/07, x4u-request at listserver.themacintoshguy.com wrote:
>>From: Tim Collier <timjcollier at mac.com>
>>Subject says it all.  I installed BellSouth DSL and connected the
>>wired modem to my 802.11n Airport Extreme.

>If it's just a modem it won't do NAT. (Although with the people who 
>name products knowing so little about technology these days, 
>anything is possible :-) ).

These DSL modems are most often modems, routers, & switches doing DHCP and NAT.

>  Anything that does NAT must have different IP ranges on each side 
>and so qualify as a router or even a gateway. If that and the 
>Airport are all the network kit you have then I can't see how you 
>can have anything that could cause any error that could be described 
>as 'Double NAT'. What item told you of the error?

And the fact that both the DSL cable modem is doing NAT and his 
AirPort is doing NAT, this causes the double NAT message.

>>From: Robert Ameeti <robert at ameeti.net>
>>Double NAT would be where the ISP's router was doing NAT and
>>providing a 'network' of addresses and then one of the devices (your
>>AirPort) hooked up to one of its ports was also doing NAT. It is not
>>impossible to deal with but should be avoided when possible.
>
>It's fairly straightforwards to deal with.

The problems that users today are dealing with is when they attempt 
to set up a site to site VPN. Doing this with a double NAT setup in 
not going to be easy with most equipment.

>You just have to think about what is going on.

>David

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Robert Ameeti

The Hawaiian alphabet has 12 letters.
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