Before you can build Exim, you have to create an "exim" user and group: # groupadd -g 222 exim # useradd -d /var/spool/exim -g exim -s /bin/false -u 222 exim The recommended uid/gid is 222, but others are fine if you prefer - see https://slackbuilds.org/uid_gid.txt for other recommendations. There's no "configure" script; instead Exim is configured by editing a well documented Makefile, which is then included during the build process. The provided "exim.Makefile" will build an all-purpose Exim daemon with the most common features. The database lookups will not be built by default, but you can enable them easily by passing the directives on the command line when calling this script, e.g. LOOKUP_JSON=yes \ LOOKUP_LDAP=yes \ LOOKUP_MYSQL=yes \ LOOKUP_PGSQL=yes \ LOOKUP_REDIS=yes \ LOOKUP_SQLITE=yes \ sh exim.SlackBuild For including the JSON, PostgreSQL and Redis lookups you'll need the "jansson", "hiredis" and "postgresql" packages respectively, all available from SlackBuilds.org. WARNING: this package is intended as a drop-in replacement for Postfix. As a result, there are some inevitable filename conflicts between Postfix and Exim. REMOVE POSTFIX BEFORE INSTALLING THIS PACKAGE!