General Security Issues

[Konstantinos Fotiadis]

Greetings list,

As a newbie to security I would like to ask any recommendation that the list
might have.
We are about to "install" a new box with 4.9 stable to the nice and innocent
internet world. :-P
The box has no services running expect apache and we telnet to it via SSH.
Main function of this box will be graphing various interfaces via rrdtool.
So, I would like to ask if there is any other precautions that I must take
in order to sleep safe at night. Should I check for any other opened ports ?
Should I do something with the kernel to be more secure ?
I know this ain't so easy, but let's say my main scope is to get a least a
decent sleep :-)

Kind Regards,

Kostas