IPsec-Protected
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... tunneling.
The document was intentionally not expanded to include the details on
how to set up an IPsec-protected tunnel in an interoperable manner,
but instead the details were deferred to this memo.
...
... networks. A detailed description of the problem and
requirements of IPsec-protected data traffic traversing a NAT is
provided in [RFC3715 ...
... More details about UDP encapsulation of IPsec-protected IP packets
can be found in [RFC3948].
...