On Sat, 21 Aug 2004 04:30:39 +0800, AccuSpam <support(_at_)accuspam(_dot_)com>
wrote:
Changes to MUAs requires *everybody* to upgrade their MUA. Changes to
MTAs require only service providers to upgrade. It will be similar to
the battle to have open relays closed
SPF with "-all" does not escape this problem.
Not all users will have to update their MUA software to benefit from SPF,
unlike SenderKeys.
It is not acceptable to run an open relay - the cost of authenticating
mail clients is already being paid. Major MUAs support SMTP AUTH. While
many SMTP servers do not require that users send mail using any particular
email address, this only weakens SPF in the sense that users of a domain
can impersonate other users of the same domain.
Nevertheless, you can still significantly reduce the quantity of spam
without upgrading or reconfiguring MUAs.
With SenderKeys, you do not reduce your volume of spam (or anyone else's)
by upgrading only your MUA; only forged communications between SenderKeys
users can effectively be blocked. If you block non-SenderKeys mail you
will miss important mail (mailing list subscriptions, bills, receipts,
etc.). If you don't block non-SenderKeys mail you will continue to
receive SPAM, although not with a FROM address of other SenderKeys users.
CU
Dobes