Theory

Components of a Linux Distribution

• Kernel
• Core GNU utilities such as bash shell
• Supplemental software such as Gnome desktop environment
• System Services (systemd)
• Software Management

Linux Distribution

• Slackware (you should compile software yourself)
• Debian
• RedHat Enterprise Linux (offers payed support)
• SUSE (offers payed support)
• Ubuntu (based on Debian)
• Fedora (desktop version of RedHat Enterprise Linux)
• OpenSUSE (open version of SUSE)
• CentOS (open version of RedHat Enterprise Linux)

Desktop Environments

• GNOME
• KDE
• XFCE
• Enlightenment
• LXDE

Server Applications

Port	Protocol	Server Application
22	SSH	OpenSSH
23	TELNET	telnetd
25	SMTP	PostFix, Sendmail
53	DNS	BIND, named, unbound
67	BOOTP	dnsmasq, dhcpd
80	HTTP	Apache, nginx
443	HTTPS	Apache, nginx

HOWTOs

Creating a New Sudo User

# 1. connect to the sever
ssh root@server_ip_address
# 2. add a new user
adduser username
# 3. add a new user to sudo group
usermod -aG sudo username
# 4. Test sudo access on new user account
su - username
sudo ls -la /root