View Source: NAT - Waikato Linux Users Group

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An [Acronym] for __N__etwork __A__ddress __T__ranslation.

[NAT] is an evil scheme to change [IP]s as they travel through a gateway. A common special case is “masquerading”, where multiple machines appear to have the gateway's [IP] address, which is necessary if you have multiple machines trying to communicate with remote hosts on the InterNet but the [ISP] only gave you one [IP] address.

If you are trapped behind [NAT] and need a realworld [IP], consider using [Teredo] to get yourself a realworld IPv6 address.

!!! Types of [NAT]

__Full cone__:
    Packets arriving at the [NAT] device for a [Port] previously used by the [NAT] device to send out packets will be routed to the host inside.
<br> __Restricted cone__:
    This is like full cone, except that the internal host must have spoken to the remote host at some point in the past.
<br> __Port restricted cone__:
    This is like restricted cone but they must have spoken to the same [IP]:[Port] before.
<br> __Symmetric__:
    Uses a seperate [Port] for every [IP]:[Port] pair. This cannot work with [Teredo] or [STUN]. This is the worst kind of [NAT].

!!! See also

* RFC:1631
* RFC:3489
* [NAPT]
* [Teredo]
* [STUN]

Last edited on Sunday, January 2, 2005 5:01:54 am by AristotlePagaltzis

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