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Re: ESP Qs
Hi,
> 1) Does IKE support indicating that anti-replay is not offered ( r to i
> ), i.e. that the ESP sequence number will not be checked?
The DOI includes a method for the responder to indicate whether or not he has
chosen to do anti-replay. See Section 4.6.3.2 (REPLAY-STATUS). See also the
archives for a whole lot of painful background on this issue...
> 2) If the sender (same as initiator?) is told that there is no checking,
> should it leave the sequence number at zero?
The achitecture says that the anti-replay sequence is always present even when
the receiver chooses not to perform anti-replay detection.
> 3) In the case of manual-keying - when anti-replay SHOULD NOT be used,
> should the value of Sequence number be left zero?
No, it just means that the sequence counter is allowed to wrap...
> 4) The IPSEC DOI seems to suggest that implicit IV is the ONLY MUST,
> with explicit IV as the 'old way'. Most implementations I've seen only
> support explicit IV.
I'm not sure where you got this. ESP_DES is listed as the only ESP MUST and
uses the cipher transform defined in:
[DES] Madson, C., Doraswamy, N., "The ESP DES-CBC Cipher Algorithm With
Explicit IV," draft-ietf-ipsec-ciph-des-expiv-02.txt.
Derrell
References:
- ESP Qs
- From: Stephen Waters <Stephen.Waters@digital.com>