TCP/IP is a suite of communications protocols for internetwork communication. It is primarily used as the communication system for the Internet.
A terminal emulation program that allows you to connect to remote computers. RHEL includes the Kerberos version of the Telnet server, as configured through the /etc/xinetd.d/krb5-telnet configuration file.
The tmpwatch command removes files that have not been accessed in a specified number of hours. The default daily tmpwatch script checks files in the /tmp and /var/tmp directories.
The umask command defines default permissions for newly created files.
Every Linux user has a user ID, as defined in /etc/passwd.
The usermod command modifies different settings in /etc/passwd, such as expiration date and additional groups.
The Very Secure FTP service is the default FTP server for RHEL.
The vgcreate command creates a volume group (VG) from one or more physical volumes (PVs) for Logical Volume Manager (LVM).
The vgdisplay command specifies current configuration information for volume groups (VGs).
The vgextend command allows you to increase the extents or space allocated to a volume group (VG).
The vi editor is a basic Linux text editor. While other editors are more popular, vi may be the only editor you have available in certain rescue environments.
You can configure multiple Web sites on a single Apache server by configuring a number of virtual hosts in your /etc/httpd/conf/httpd.conf configuration file.
Virtualization is an abstraction of computer resources; most often associated with platform virtualization, in which you can include one or more virtual machines on a physical system. Two options for virtualization are VMware and Xen.
VMware is a proprietary system with virtualization products freely available to all. With snapshots, it can help you test a system with less risk. I've written much of this book with RHEL installed on a VMware Server.
A collection of physical volumes (PVs) in Logical Volume Manager (LVM).
The window manager is a special type of X client that controls how other X clients appear on your display.
WINS provides name resolution on Microsoft networks; it can be activated on Samba.
An X client is an application that uses the X server services to display output.
The X Display is a console and a virtual window. By default, there are six virtual text consoles configured with Linux; the X Display is associated with virtual console number seven.
The X server is the part of the X Window System that runs on your desktop. The X server draws images on your screen, takes input from your keyboard and mouse, and controls access to your display.
The GUI for Linux is also known as the X Window. Unlike other applications, the X Window System is a layered application.
Xen is the native virtualization technology to RHEL. It requires the use of a custom Xen kernel and can support virtual machines in paravirtualized and fully hardware virtualized modes.
The xhost command can be used to allow other hosts to access your X server. In other words, you can configure remote X clients to send their display to the local X server.
The xinetd "super-server" daemon controls connections to servers in the /etc/xinetd.d directory such as the rsync and Kerberos Telnet servers.
The X.org server is the default X server for RHEL.