Getting my previously dip-my-toe-in-the-water level Linux server and cli skills up to scratch.
Starting with some learn-by-doing in a VM, with Ubuntu Server (LTS), and getting all basic services installed, configured, working and secured (LAMP, mail, SSH, file, print, etc).
Beyond IPTables+UFW, deny everything, allow specifically whats needed, from where it's needed, disabling unused services, changing SSH port, using strong passwords, users/groups configured well, root disabled, using DenyHosts and fail2ban, a/v, antispam, and generating/analyzing/reading reports from logs, what else should I be investigating?
I have a bunch of websites lined up to read, many of which rehash the same information, but some of which have more information or avenues for security (or failure as the case may be).
Would be good to get some info straight from some of the knowledgable people around here.