To enable SpamAssassin on VPS, we need to install it first. Before installing SpamAssassin, ensure have the perl/cpan requirements.

1. Install the following required modules

   cpan -i Archive::Tar Digest::SHA Net::DNS Net::DNS::Resolver::Programmable Mail::SPF Geo::IP Net::CIDR::Lite IO::Socket::IP \
   IP::Country Net::Ident Net::Patricia IO::Socket::INET6 Compress::Zlib Mail::DKIM LWP::UserAgent HTTP::Date Encode::Detect ExtUtils::MakeMaker \
   NetAddr::IP Mail::SpamAssassin::Plugin::Razor2 Razor2::Client::Agent IO::Socket::SSL DBI Sys::Syslog DBD::File

2. Use CustomBuild to install SpamAssassin:

   cd /usr/local/directadmin/custombuild
   ./build set spamd spamassassin
   ./build spamassassin

3. Once setup, and exim is restarted, spamd should be running, confirm with:

   ps ax |grep spamd

4. SpamAssassin is setup and running!

https://help.directadmin.com/item.php?id=36