Blacklists are a popular way to block spam. It is easy to add them to the GWIA configuration and they can be very effective but there are situations where it is necessary to accept email form certain IP addresses that may have been blacklisted. Currently, there is no way to override a blacklisted IP address.

It's true that products like Secure Messaging Gateway can address issues like these but that is a rather large expense for a small GroupWise system especially when the same could be accomplished within the GWIA by creating a small exception list.