GNU Mailutils

tcp-wrappers {
  # Enable TCP wrapper access control.
  enable bool;
  # Set daemon name for TCP wrapper lookups.
  daemon name;
  # Use file for positive client address access control.
  allow-table file;
  # Use file for negative client address access control.
  deny-table file;
  # Log allowed accesses at this syslog priority.
  allow-syslog-priority prio;
  # Log denied accesses at this syslog priority.
  deny-syslog-priority prio;
}