Category Archives: Linux Administration
Increase Amazon EBS Volume of a Linux EC2 instance
Increasing the size of a EBS volume is sadly not as easy as tweaking a value. Amazon AWS does not support changing the Volume size on the fly. But there are ways to increase the size. Continue reading
Access SSH server without direct connection from the internet
When two servers are connected to each other but only one server has access to the internet, it is always uncomfortable to connect to the server without internet connection. Specially when files need to be copied to the server without direct internet connection. There is a way to make it more comfortable to connect via ssh. Continue reading
PHP Unable to load library module.so
If you see in the Apache error_log log-file an error like “Unable to load dynamic library /usr/lib/php/modules/module.so”, you probably have CentOS 6.4 which has a configuration issue in the mcrypt configuration file. Continue reading
Set up apache and the log path with SELinux
Depending on your backup strategy you might run into troubles of backup the entire /etc directory. Running a default installed Apache on CentOS will have the log directory of Apache linked from within the /etc/httpd/ directory. If you backup solution would backup those as well, the backups would contain the logs and get huge. Continue reading
Find the man page that contains a certain string
Most of the time you might know what program you need and you open the related man page to find the programs parameters. But what if you do not know which man page contains the information you are looking for?
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Restrict SSH login using SSH keys to a particular IP address
Because most passwords are quite short so you can remember them as well as it is annoying to type the password all the time, You might have already considered creating SSH-keys and configured the SSH passwordless login with SSH-key for your server. But how to secure the access with SSH-key? Continue reading
Secure SSH server access
With a server running, SSH is one of the services nearly instantly gets checked out. Only after a couple of hours of going live with your server, you might already notice someone trying to login with passwords from a dictionary. There are some things you can do to reduce those hacking attempts to your SSH server. Continue reading
Change SSH port in CentOS with SELinux
Since version 4 of CentOS, SELinux is providing an additional layer of security to the Linux distribution. As of SELinux in combination with sshd, changing the port or even listening on 2 ports is not as easy as just changing the sshd configuration file. Continue reading
yum – install package that contains a specific file
When i realised that the program to manage the SELinux rules is called “semanage” i tried to find a package of the same name in the yum repositories. But i could not find it. So i had to find it inside the yum repository. I am happy that yum provides an easy way to find a file that is provided within a package. Continue reading
Setup Amazon AWS EC2 instance with CentOS
The Amazon AWS provide a so called Free Tier. This is a free subscription for all the AWS services for one year. It includes EC2 instance and EBS Volumes which is nice to test the AWS service. See details about the included services and there limitations at AWS Free Usage Tier. Continue reading
