Tips to use Linux servers
Linux is very wide used today for dedicated servers because of its cost efficiency and security. Linux is really secure to use, both for desktop and servers, however most Linux servers generally come without any protection pre-configured by default and sometimes it can come with many services installed that are not required, including Web Servters, FTP Servers, Mail Servers and SSH Remote Access. Here are some useful tips and techniques you can use to strengthen the security of your Linux servers
1 – Use strong Passwords
This is obvious. If someone finds out your root password, he can control your whole system easily. Therefore you should always create long and complicated passwords that contain upper and lower case letters, numbers and non alpha-numeric characters. Also remember to enforce password ageing so users need to change their passwords regularly. Lock user accounts after a certain number of failed login attempts.
2 – Use Centralized Password Server
Consider implementing either a LDAP or Kerebos server to perform password authentication. This allows for a central database to maintain user’s passwords between multiple servers for easy management. This prevents user account and password data from becoming inconsistent and out of date, and prevents user accounts that should have been deleted on all servers being left behind on one server.
3 – Use Public/Private Keys
Make use of Public/Private SSH keys for login of remote users instead of passwords, this provides the benefit of turning off password authentication in SSH so that your server can’t be Brute-Force cracked. However this does introduce a new problem whereby a malicious person could compromise a user’s computer or steal their laptop and then have access to the server. This can be overcome by using a password on the client certificate which must be entered before connecting, a kind of two factor authentication.
4 – Minimize software
For server usage, you should try to use as least softwares as possible. Only install those packages that are really mandatory, some distros come preconfigured with many software packages that you may never need or use. When installing always choose the Minimal Installation or Manual Installation option if they exist. Then simply install the software that you actually need.
5 – Update software often
It is always recommended to keep your software packages up to date, such as ensuring the latest version of Apache, MySQL and PHP on a standard LAMP setup will protect you against any vulnerabilities that have been discovered in previous versions. However, also make sure that the new packages work properly.
6 – Remove X Windows
Everything that you can do with the GUI can be done using the command line. So removing X Windows will not only improve security but also performance because you will save the system resources that are used for displaying the GUI.
7 – Keep tracks of all Logs
Setup logging and auditing software to track errors and changes to your servers, such as Auditd and Logwatch/Logcheck. Consider configuring a remote logging server that is updated regularly to protect against an intruder compromising your log files without your knowledge.