My First 5 Minutes On A Server; Or, Essential Security for Linux Servers
plusbryan.com/my-first-5-minutes-on-a-server-or-essential-security-for-linux-servers
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Server security doesnt need to be complicated. My security philosophy is simple: adopt principles that will protect you from the most frequent attack vectors, while keeping administration efficient enough that you wont develop security cruft. If you use your first 5 minutes on a server wisely, I believe you can do that.