+# perform lookup per host. The default behaviour is to remove the last number of the IP
+# to match a domain. This behaviour is disabled if a part of the IP is contained in the
+# hostname (look like a dialup ip from a provider). With this flag on, the "domain"
+# matching is always disable.
+# - no_sender: boolean (default: false)
+# do not use the sender address. Default behaviour is to greylist using the tuple
+# (client_address, sender, recipient). With this flag on, the sender is not used.
+# - no_recipient: boolean (default: false)
+# same as no_sender but with recipient.