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##### 9.18.6.5 Blackholes

— Variable: spam-use-blackholes

> This option is disabled by default. You can let Gnus consult the blackhole-type distributed spam processing systems (DCC, for instance) when you set this option. The variable `spam-blackhole-servers` holds the list of blackhole servers Gnus will consult. The current list is fairly comprehensive, but make sure to let us know if it contains outdated servers.

> The blackhole check uses the `dig.el` package, but you can tell `spam.el` to use `dns.el` instead for better performance if you set `spam-use-dig` to `nil`. It is not recommended at this time to set `spam-use-dig` to `nil` despite the possible performance improvements, because some users may be unable to use it, but you can try it and see if it works for you.

— Variable: spam-blackhole-servers

> The list of servers to consult for blackhole checks.

— Variable: spam-blackhole-good-server-regex

> A regular expression for IPs that should not be checked against the blackhole server list. When set to `nil`, it has no effect.

— Variable: spam-use-dig

> Use the `dig.el` package instead of the `dns.el` package. The default setting of `t` is recommended.

Blackhole checks are done only on incoming mail. There is no spam or ham processor for blackholes.