RHEL Howtos and Guides

Red Hat Enterprise Linux server tutorial for new and advanced users. Topic includes RHEL firewall, package management, Red Hat server security, various server configuration, mail-server, web-server, proxy-server, intrnet-server, file server and much more ( rss feed ).

I am using NFS server version 4.x on a CentOS/RHEL based system. I’m mounting my shared /var/www/ directory on five Apache based nodes using the following syntax:

mount -t nfs4 -o rw,intr,hard,proto=tcp rocknas02:/httproot/www /var/www/

I noticed that due to bug in my app user can sometime upload executable or other device files to get out of chrooted Apache server. How can I prevent such security issues on a CentOS or RHEL based NFS client and sever setup?


I am a new RHEL / Centos Linux server admin. I would like yum to update all packages except the Linux Kernel. How can I prevent yum command from updating kernel on a CentOS/RHEL/Fedora Linux based systems?


I am a new CentOS / RHEL 6.x server user and DevOP. I need to lock a package called nginx on a server being updated via yum command. How do I lock package version at a particular version on CentOS / Red Hat Enterprise Linux (RHEL) 6.x or Fedora Linux?


I am a new CentOS Linux user. How do I change default sshd tcp port # 22 to 2022 on CentOS Linux version 5/6?


Is there is a tool that can provide me a maximum of information (such as cpu, disk I/O, network, nfsd, memory and more) about my Linux/Unix server in a minimum of space in a terminal?


I am a new CentOS / RHEL / Red Hat / Fedora Linux server user. I need to provide tidy library support using php. How do I install php-tidy on RHEL or CentOS Linux for Apache server?


I would like to see detailed information on the history of yum transactions such as updates, deleted packages, and other information. How do I see history of yum commands on CentOS / RHEL 6.x based server? How do I undo or redo or rollback packages using yum command?