This option was removed in https://github.com/NLnetLabs/unbound/commit/ff8fd0be5c529e7a1b84e8c74426e9c531c0a8f8 but reintroduced in https://github.com/NLnetLabs/unbound/commit/c32b9e4ba95983146eac805719db720f02a64358 Disable it with commentary in hope to prevent slipping it in again.
Unbound
Unbound is a validating, recursive, caching DNS resolver. It is designed to be fast and lean and incorporates modern features based on open standards. If you have any feedback, we would love to hear from you. Don’t hesitate to create an issue on Github or post a message on the Unbound mailing list. You can learn more about Unbound by reading our documentation.
Compiling
Make sure you have the C toolchain, OpenSSL and its include files, and libexpat installed. Unbound can be compiled and installed using:
./configure && make && make install
You can use libevent if you want. libevent is useful when using many (10000) outgoing ports. By default max 256 ports are opened at the same time and the builtin alternative is equally capable and a little faster.
Use the --with-libevent=dir configure option to compile Unbound with libevent
support.
Unbound configuration
All of Unbound's configuration options are described in the man pages, which will be installed and are available on the Unbound documentation page.
An example configuration file is located in doc/example.conf.