3.2 NAT Traversal Details

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Using the notation specified in [RFC2409] section 3.2, the generalized form of an IKE phase 1 exchange that uses NAT-T is as shown in the following figure and as specified in [RFC3947] section 3.2.

IKE phase 1 exchange using NAT-T

Figure 1: IKE phase 1 exchange using NAT-T

The description in this section uses the message numbers from the protocol sequence diagram.

The IKE NAT Traversal Protocol extension exists in two revisions. The [RFC3947] revision is specified in [RFC3947]. The [DRAFT-NATT] revision is identical to the [RFC3947] revision, except that the values used for the types defined in sections 2.2.1 and 2.2.2 are those that are specified in [DRAFT-NATT], instead of those that are specified in [RFC3947]. Both revisions include the negotiation of a choice of revision supported by both peers.<13> For more information, see [DRAFT-NATT].