Install the Rar/Unrar Binaries
AlmaLinux / CloudLinux
Download the latest RAR packages for Linux x64 from rarlab.com. Note: These third party binaries are for x86 only. ARM is not supported. Extract the tar.gz package and copy the rar and unrar binaries to your /usr/local/bin directory:
wget https://www.rarlab.com/rar/rarlinux-x64-722.tar.gz
tar -zxvf rarlinux-x64-722.tar.gz
cd rar
cp rar unrar /usr/local/bin
Debian / Ubuntu
Debian / Ubuntu servers should also edit the file /etc/amavis/conf.d/01-debian and un-comment the non-free version and comment out the unrar-free entry. (The free version only supports older versions of .rar). After you are done the lines should look like this:
$unrar = ['rar', 'unrar']; #disabled (non-free, no security support)
#$unrar = ['unrar-free'];
Restart Amavis
// Centos/RHEL/CloudLinux/AlmaLinux
systemctl restart amavisd
// Debian/Ubuntu
systemctl restart amavis
Important
It is important that you always keep these binaries updated regularly as Rarlab releases new versions as older versions can contain security vulnerabilities.