Hardening against attacks?

[Dallas]

I am looking for recommendations in hardening RedHat 8.0 from both virus and attacks, to protect a network. I currently use (4) Rehat 7.1, based x86 systems to protect an internal network.   However, I am tired of finding someone or mostly servers/pc's that have been taken over without the owners knowledge attacking us. Or probing for holes.   I want to find a monitoring software that will detect an attack, find the source and send an abuse report & notify me, maybe more.