SMPT and PIX firewall SMTP Fixup

I have heard/read that the Cisco PIX firewall SMPT Fixup causes problems with native SMTP on Domino. We are now running SMTPMTA on the iSeries. We, of course, need to change that going to Domino 6. Does any one know the details?

Subject: SMPT and PIX firewall SMTP Fixup

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