Hello,

My name is Nedzhip, I'm 34 yrs old and is working as a Windows Server Administrator since 12 years.
The problem is the company I'm working for decided to move to LINUX. They just started to translate current site from asp to php and mssql to mysql, the move will be 3 months later, this means if I don't learn Linux Server Administration within 3 months I will lose my job

I just installed an CentOS to a virtual machine and started to training on it.
Not so long after I just learned the basic commands and managed to install and configure the required servers. There is no problem till there.

The problem is the security part I have no clue what are the security vulnerabilities in Linux, how is the update system working, what's the most vulnerable and exploited things and so on.
Do I have to install antivirus, and if there are any companies offering good antivirus for the Linux system.
Overall I know nothing about the security part.

What I'm asking for is a book or any other source for Linux Server administration especially for security part, since I'm finding my way with tutorials etc. about the other things.

Thank you in advance, and sorry for my bad English!

For administration and security read HOWTO's from http://www.tldp.org

And by updating the system the security bugs as well as normal bugs are fixed.

An antivirus is not normally used. Though it's used for email attachment scanning. But rootkit is prevented using rkhunter, chkrootkit programs.

You should definetly get a book on security and on administration.

Recommended websites:

1) http://lwn.net

2) http://www.lxer.com

3) http://phoronix.com

Meh, you got plenty of time, Nedzhip. No Worries.

What you need to know depends on what you are going to do. If you can tell me a little more about the tasks you're going to be asked to do ( "Windows Server Administrator" is a really, really big skill set. What portion of that do you use every day?) I can better tell you what you'll need to learn first.

Also, it would help a lot if you can tell me what you already know (synopsis, please) about Linux. The Distro (version/operating system name) of the platform your company is migrating to would also help to narrow down what you're going to have to read and practice.

Re updates: Linux distros eg Centos have official repositories eg see /etc/yum.repos.d dir. normally you would only get stuff via these repos; never from random websites.
Normally the system will check the repos for updates automatically, but (default) will not install unless you ask it to.

This is a good site full of books/manuals (free to read ) www.linuxtopia.org .
See particularly the Admin and Security sections.

As above, knowing which distro your company will use and some more specifics on what you want to learn next would help.

I am a Linux Systems Administrator who works with RHEL/CentOS on a regular basis. Just some quick advice on securing your server in addition to the reading the others suggested.

* You need to get the IPTables firewall up and running immediately. This is the most important, and first step.

* If you are administering the server remotely, configure SSH to use key based authentication and not password based. Never allow root logons to SSH or any other service.

* A lot of administrators disable SELinux (Security Enhanced Linux). If you are serious about security, learn how to use it.

* The only free anti-virus I know of for Linux is ClamAV. It isn't a bad idea to get that service up and running, but not of paramount importance.

* You should strongly consider a good IDS (intrusion detection system) like Tripwire or Snort. These will take some time to learn so look into this last.

* And as with any Windows system, update the system regularly. Linux has vulnerabilities that come up from time to time, just not as many as Windows.

These suggestions are the range of what I use in production environment servers. Just remember, there is no such thing as a server that can't be hacked. If your attacker is knowledgeable enough, has enough time, and is determined, he can get into your system. Make plans for WHEN your server is hacked. Make imaged backups on a regular basis with the imaging software of your choice. Security does not end with intrusion prevention and detection. Disaster recovery is also a part of the complete security plan.

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Here are some sites that have greatly assisted me in learning linux:

Very simple, powerful commands (favorite)
Linux Filesystem structure
http://www.tldp.org/HOWTO/Unix-and-I...WTO/index.html
File Permissions

Since you're coming from windows to linux (optional)