New server setup steps [closed]

Question

I'm interested in the steps you make when you need to set up a new Linux (preferably CentOS) server, putting a emphasis on security, like changing SSH port, limiting root SSH access, etc.

Answer 1

I usually don't change SSH port, because it complicates setups (now I should remember which port I use on which server and I have 20+ of them) and confuses me and my customers. I use DenyHosts instead, it is available from an EPEL repo. It's also good to disable password-based authentication in favor of key-based in sshd_config (PasswordAuthentication no and PubkeyAuthentication yes), at least for the root account (PermitRootLogin without-password). Of course empty passwords should be disabled, but I think it's a default setting nowadays (PermitEmptyPasswords no).