So over that last few weeks the 2.8 firmware update for Lotus Protector for Mail Security (LPMS) rolled out. It adds some nice features but after the upgrade some STS customers (and ourselves) saw reverse DNS issues after the upgrade. Specifically LPMS would seem to drop emails even when a correct reverse was available in DNS for the sending server.

Off we go to PMR land and within a day or so IBM came back with this suggestion that has cleared up the issue:

1. Disable the Border IP Check at 'Mail Security | Policy | Advanced Parameters'
--> set smtp.border_ip_checks.enable from 1 to 0

2. Re-enable the following Receiving SMTP settings:
Enable Reverse DNS Lookup

So far it has worked for us and the customers who we help manage.