To start the blog I'm going to be listing the topics that I think are the most important to know if you want to become a Linux Admin. (Part 1 / 2)
These topics involves everything from performing maintenance on your Servers, to managing the users on the network to making sure the copy machine works.
Some topics will be a bit vague because the topic itself is very broad and involves a lot of information and once we get to that topic in the blog we'll go into a lot more detail about it.
The topics will also be numbered based on importance and what I think you should be starting out with when you want to learn how to become a Linux administrator. So to make it easier for yourself follow the numbers because some things are easier to learn if you have some background knowledge about other topics (like knowing the basics about CentOS before you start messing with networking and SELinux). These are not the only things that'll be discussed in this blog but these are the topics I personally think you should focus on and then when you know this you can start to explore the other topics discussed in this blog.
# - Servers, distros:
1. CentOS (and Red Hat Enterprise Linux).
1. Ubuntu server or Debian.
# - Desktop, distros:
2. Ubuntu (or any Ubuntu-based distro, like Linux Mint, more on this when we get to this topic) or Debian.
# - Networking:
1. Basic networking, like what is TCP/IP, how do computers communicate with each other, how do I monitor a network, how to I create different local networks inside the network.
2. File servers, what are they, how do they work, why are they important and how do I secure them?
3. Network printers, how do I set up a network printer and how do I secure it?
4. Routers and hardware firewalls, for example CISCO Routers.
5. Centralized authentication and administration of many hosts.
6. Network security, what do I need, how should it be set up, why is it important?
7. Proxies, like Squid. Why should I use one and how do they work?
# - Security:
1. SELinux, very important that you learn this as soon as possible because it really enhances your security AND it's easier if you learn how to implement it while also learning about servers and daemons instead of learning about daemons and THEN learning about SELinux, because it takes some time to fully learn and understand the principles behind SELinux.
2. SSH Aliases. SSH is the primary way that you'll be administrating your linux based servers and if you have made aliases for every host together with SSH keys you're much more secure, both against brute force attacks and people looking behind your shoulder when you're logging in.
3. Users and groups. Learn to properly add users to groups and it'll be a lot easier to manage your users on your hosts. For example by adding every employee from the accounting department to the group "Accounting". Then the user has access to every file and folder that the group has access to, saving both time and trouble because you know it won't be any permission problems and you can't forget to give the user access to something important.
4. Setuid, Setgid and file permissions. Properly set permissions on files and folders reduces the the ability for your users to access things they shouldn't.