Use:
~smtpclientblocks~
<format string>
~end~
The format string can have the replacements
address - IP address (returned as host address or CIDR address as appropriate)
date - the date/time the address was added to the database in YYYYMMDDHHMMSS format
expiry - the date/time the address is set to expire in YYYYMMDDHHMMSS format
reason - the user who added the address or 'auto' if the block was added by VPOP3 automatically
Note that this only returns the blocks which have not yet expired. The database stores blocks for 30 days after expiry as a basic audit trail, those can only be accessed from the database directly.