> Perfect, so following your argumentation here, scrub should "normalize" 
> the packets to
> ensure "the end host will reassemble those packets"

No.  Normalization ensures passive intermediate hosts will reassemble
the packets the same way as the end host does.
 
> That mean to me:
>  1) Reassemble the packet
>  2) *Remove* the DF bit (since PMTU will stop here anyway)
>  3) Send it to the new host (possibly refragmenting it, but *without* 
> the DF)

it would make sense to extend the behavior of 'no-df' rules to cover
that and allow scrub to operate more in the 'fragment reassembly' sense
than in the normalization sense.
 
> BTW, if the "end host" is "this host" (like in my NFS case) there is no 
> ambiguities, we know we do accept theses packets.

The administrator may know that but neither the firewall or an
intermediate IDS will.

.mike

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