How to block all traffic from a spamming server

How do I add redirect instructions to my .htaccess file to prevent hits from spamming servers?

Example: If there is a spamming server called xxx-xxx-xx-xxx.broadband.example.net, but the subdomain keeps changing in ways such as xxx-xxx-xx-xxx-abc.broadband.example.net, you can add the following entries to your .ht access file to have all traffic from the server redirected elsewhere:

RewriteCond %{HTTP_REFERER} broadband\.example\.net
RewriteRule ^ https://www.anotherdomain.com/? [R=301,L]