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CentOS Howtos and Tutorials

Centos Linux tutorial for beginners and advanced users with special focus on security, firewall, web, mail, file and proxy servers in an enterprise environment (rss feed).

A very serious security problem has been found in the virtual floppy drive QEMU's code used by many computer virtualization platforms including Xen, KVM, VirtualBox, and the native QEMU client. It is called VENOM vulnerability. How can I fix VENOM vulnerability and protect my Linux server against the attack? How do I verify that my server has been fixed against the VENOM vulnerability?
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How To CentOS / RHEL 7 Install Gnome Desktop Using Yum

I installed minimal CentOS Linux 7.x on my laptop. How can I install Gnome desktop GUI on a RHEL (Red Hat) 7 or CentOS Linux 7 system using command line option?
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RHEL / Centos Linux 7: Change and Set Hostname Command

I'm a new RHEL (Red Hat Linux) and/or CentOS Linux 7 server user. How can I change the hostname in CentOS 7 using a command line option?
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CentOS/RHEL Use yum Command To Downgrade or Rollback Updates

I'm a CentOS Linux 7.x server user. How can I use yum command to downgrade or rollback package updates on a RHEL (Red Hat)/CentOS/Scientific Linux server?
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RHEL / CentOS Linux 7 Enable Ping Access In Docker Container

I'm using RHEL 7.1-4 container on a RHEL /CentOS Linux 7.x server. However, I'm unable to ping external site/IP address using the ping command. I'm getting the following error on screen:

ping: Operation not permitted

How do I fix this problem?
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How To Mount a Remote Directory With SSHFS on a Linux

How can I mount a remote directory with ssh on a Linux bases system? How do I use SSHFS to mount remote file systems over SSH on a Ubuntu or Debian/RHEL/CentOS/Arch Linux system?
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Linux Change Disk Label Name on EXT2 / EXT3 / EXT4 File Systems

How can I modify partition labels on a Linux operating systems? How to change disk name on the ext4 file system on a Ubuntu Linux using command line?
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Ubuntu Linux: Edit and Open Files That Require Administrator Privileges

There are certain files in Ubuntu Linux (or Unix-like systems) that only root user access or edit. How can I edit and/or open files that requires admin (root) access on a Ubuntu Linux?
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Bash: Reissue And Repeat A Long Command Without Retyping It on a Linux, OS X & Unix

I'm a new Ubuntu Linux user. In Linux, Apple OS X or Unix-like systems, how do I reissue or repeat a long command without retying it?
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How To Patch and Protect Linux Server Against the Glibc GHOST Vulnerability # CVE-2015-0235

A very serious security problem has been found in the GNU C Library (Glibc) called GHOST. How can I fix GHOST vulnerability and protect my Linux server against the attack? How do I verify that my server has been fixed against the Glibc GHOST vulnerability?
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