M-P

masquerading

Masquerading enables you to provide Internet access to all of the computers on a LAN with a single public IP address.

MBR (Master Boot Record)

The first sector of a bootable disk. Once the BIOS cycle is complete, it looks for a pointer on the boot disk's MBR, which then looks at a boot loader configuration file such as grub.conf to see how to start an operating system.

mdadm

The mdadm command can help you view and configure RAID arrays.

mkbootdisk

The mkbootdisk command can create a boot disk, customized for your system.

mkfs

The mkfs command can help you format a newly configured partition. Variations are available including mkfs.ext3, which formats to the default ext3 filesystem.

modprobe

You can use the modprobe command to control device modules to be installed.

mount

You can use the mount command to specify mounted partitions, or attach local or network partitions to specified directories.

mount.cifs and umount.cifs

The mount.cifs and umount.cifs commands, when properly configured, allow regular users to mount directories shared over a Microsoft Windows network through Samba.

NAT (Network Address Translation)

NAT is a feature associated with firewall commands such as iptables, which connects computers inside your LAN to the Internet while disguising their true IP addresses. NAT modifies IP packet headers. The process is reversed for return messages. Closely related to masquerading.

netstat

The netstat command displays connectivity information for your network cards. For example, the netstat -r command is used to display the routing tables as stored in your kernel.

Network Time Protocol (NTP)

The Network Time Protocol allows you to synchronize your computer with a central timeserver. You can do this on RHEL with the Date/Time Configuration tool or by editing /etc/ntpd.conf and activating the ntpd service.

NFS (Network File System)

NFS is a file-sharing protocol originally developed by Sun Microsystems; it is the networked filesystem most commonly used for networks of Linux and Unix computers.

NIC (Network Interface Card)

A NIC connects your computer to a network. A NIC can be anything from a Gigabit Ethernet adapter to a telephone modem.

NIS (Network Information System)

NIS allows you to share one centrally managed authorization database for the Linux and Unix systems on your network.

PAM (Pluggable Authentication Module)

PAM separates the authentication process from individual applications. PAM consists of a set of dynamically loadable library modules that configures how an application verifies its users before allowing access.

parted parted

is a standard disk partition command utility that allows you to modify the physical and logical disk partition layout. Be careful when using it, as changes are immediately written to the partition table.

partprobe

You can use the partprobe command to reread a recently changed partition table without rebooting.

PATH

A shell variable that specifies the directories (and in what order) the shell automatically searches for input commands and files.

PGP (Pretty Good Privacy)

A technique for encrypting messages, often used for e-mail. It includes a secure private- and public-key system similar to RSA. The Linux version of PGP is known as GPG (GNU Privacy Guard).

physical extent (PE)

A chunk of disk space created from a physical volume (PV) for Logical Volume Manager (LVM).

physical volume (PV)

An area of space for Logical Volume Manager (LVM) that usually corresponds to a partition or a hard drive.

Pirut

Pirut is the name of the RHEL package management tool.

Primary ATA (PATA)

Primary ATA is the media standard associated with older IDE drives, also known as ATA (Advanced Technology Attachment).

Primary Domain Controller (PDC)

A PDC is the governing server on a Microsoft Windows NT 4 network. You can configure RHEL with Samba to function as a PDC or as a member server on more current Microsoft networks.

/proc

/proc is the Linux virtual filesystem. Virtual means that it doesn't occupy real disk space. /proc files are used to provide information on kernel configuration and device status.

public/private key

Encryption standards such as PGP, GPG, or RSA are based on public/private key pairs. The private key is kept on the local computer; others can decrypt it with the public key.

Pup

Pup is short for the Package Updater, which monitors the Red Hat Network (RHN) for packages available for update.

pvcreate

The pvcreate command allows you to configure physical extents (PEs) from a properly configured partition.

pvdisplay

The pvdisplay command specifies current configuration information for physical volumes (PVs).