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UNIX ADMIN FINAL
Unix Admin Final
293
Computer Science
Undergraduate 4
12/07/2013
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Term
tar
 Definition
Reads multiple files or directories and packages them into one file, often a tape file.
Term
tar
 Definition
_____ useful way to back up any files whose near-term recovery you anticipate
Term
tar
 Definition
____ preserves ownership and time information, but only if you ask it to.
Term
create a tar file
 Definition
tar -cvwf file.tar myfile.txt
Term
create a tar file named home.tar containing the home directory and place that file in the current directory.
 Definition
tar -cvwf home.tar home/
Term
Extracting the files from a tar file:
 Definition
tar -xvwf myfile.tar
Term
unarchive (untar) the myfile.tar.gz file in the current directory
 Definition
tar -xvwzf myfile.tar.gz
Term
Creating a tarred file that is compressed with bzip
 Definition
tar -cjvf test.tbz home/
Term
Create archive files
 Definition
tar -cf
Term
extract archive files
 Definition
tar -xf
Term
preserves ownership and time information
 Definition
tar --atime-preserve
Term
lets you specify a “blocking factor”
 Definition
tar -b
Term
reduces the size of the named files using Lempel-Ziv coding. Whenever possible, each file is replaced by one with the extension .gz, while keeping the same ownership modes, access and modification times.
 Definition
gzip
Term
Compress <filename>
 Definition
gzip <filename>
Term
Decompress <filename>
 Definition
gzip –d or gunzip <filename>
Term
command changes the permissions on a file.
 Definition
chmod
Term
T/F Only the owner of the file and the superuser can change its permissions.
 Definition
True.
Term
set permissions recursively
 Definition
chmod –R
Term
u+w
 Definition
adds write permission for the owner of the file
Term
ug=rw,o=r
 Definition
gives the r/w permission to the owner and group, and read permission to others
Term
a-x
 Definition
Removes execute permission for all categories (owner/group/other)
Term
ug=srx,o=
 Definition
Makes the file setuid and setgid and gives r/x permission to the owner and group only
Term
g=u
 Definition
Makes the group permissions be the same as the owner permissions
Term
command changes a file’s ownership and group ownership
 Definition
chown
Term
Options to recursively change file and directory user ownership
 Definition
chown –R <username>:<groupname> ~<username>
change owner recursively
Term
just like the chown command.
 Definition
chgrp
Term
Options to recursively change file and directory group ownership
 Definition
chgrp –R
Term
command is most often used to terminate a process
 Definition
kill
Term
can send any signal, but by default it sends a TERM
 Definition
Kill
Term
guarantees superkill
 Definition
kill –KILL (or -9) <pid>
Term
restarts the process.
 Definition
kill -HUP pid:
Term
interrupts the process.
 Definition
kill -INT pid:
Term
aborts the process and gets dumps info
 Definition
kill -ABRT pid:
Term
let the process to continue
 Definition
kill –CONT pid:
Term
is the system administrator’s main tool for monitoring processes.
 Definition
ps
Term
general overview of all the processes
 Definition
ps –aux
Term
Interactive Linux Tasks Status Display – The top command provides a regularly updated summary of active processes and their use of resources.
 Definition
top
Term
command searches the given file for lines containing a match to the given strings or words.
 Definition
grep
Term
All files or all matching strings (wild cards)
 Definition
*
Term
Single character
 Definition
?
Term
What are the components of a Linux distribution?
 Definition
o Kernel
o Desktop Environment
o File structure
Term
Popular Distributions
 Definition
o Redhat
o Fedora
o Suse
o Debian
o CentOS
Term
From what sources can Linux be installed?
 Definition
o CD-ROM
o Hard disk
o Floppy disk, USB device
o Network installation
o ftp
o http
o nfs
Term
The Linux kernel was initially conceived and created by Finnish computer science student Linus Torvalds in 1991.
 Definition
Who created the Linux Kernel?
Term
What does open source mean?
 Definition
Open source is a philosophy of software distribution that allows anyone to read and modify the program's source code.
Term
Where is the kernel stored on a CentOS distro?
 Definition
/boot
Term
As the Linux kernel matured, the size of the kernels generated by users grew beyond the limited imposed by some architectures, where the space available to store the compressed kernel code is limited.
 Definition
bzImage
Term
is a statically linked executable file that contains the Linux kernel in one of the executable file formats supported by Linux.
 Definition
vmlinux
Term
What is a hard drive partition?
 Definition
A hard drive partition is part of the drive, or a section, treated by the operating system as an independent storage area or drive.
Term
is a commonly used name for a command-line utility that provides disk partitioning functions in a operating system.
 Definition
fdisk
Term
is a graphical toll for partitions management and mount point association during installation.
 Definition
disk druid
Term
program that partitions your hard drive for you
 Definition
Disk Druid
Term
is the standard Unix command for formatting a disk partition with a specific filesystem.
 Definition
mkfs
Term
mkfs mountpoint
 Definition
mkfs –t
Term
is used to build a Linux file system on a device, usually a hard disk partition.
 Definition
mkfs
Term
is a tool for checking the consistency of a filesystem in Unix and Linux.
 Definition
fsck
Term
automatically repairs the filesystem without any questions
 Definition
fsck -a
Term
used to check and optionally repair one or more file systems.
 Definition
fsck
Term
exit code 0
 Definition
no errors
Term
exit code 1
 Definition
filesysten errirs corructed
Term
exit code 2
 Definition
System should be rebooted
Term
exit code 4
 Definition
File System errors left uncorrected
Term
exit code 8
 Definition
operational error
Term
exit code 16
 Definition
usage or syntax error
Term
exit code 32
 Definition
Fsck canceled by user request
Term
exit code 128
 Definition
share library error
Term
can be thought of as extra RAM, but on disk.
 Definition
swap
Term
independent section of the hard disk that is used for swapping
 Definition
swap partition
Term
A swap is a process where ____ of memory is copied to the preconfigured space of the _____, to free up that page of memory
 Definition
pages (chunks) , hard disk (swap space)
Term
Create the swap partition using parted or fdisk
 Definition
1. type mkswap /dev/hdb2
2. type swapon /dev/hdb2
2. edit /etc/fstad to include /dev/hdb2 swap swap defaults 0 0
Term
Does the system need swap space to work?
 Definition
It is not required, but it is very recommendable.
Term
method by which information is stored on disk drives.
 Definition
filesystem
Term
default file system for many Linux distributions
 Definition
ext2
Term
ext2 plus journaling, which means that no fsck is required after a power failure
 Definition
ext3
Term
newer file systems, similar to ext2, but improve on various aspects (journaling, speed, size, efficiency)
 Definition
reiserfs, xfs
Term
used by most cd-roms
 Definition
iso9660
Term
special virtual file system, none of the files actually exist, but they are created by the kernel on the fly, eg cat /proc/filsystems contains a list of supported file system types on the current system.
 Definition
proc
Term
virtual file system for devices
 Definition
devfs
Term
What are disk quotas
 Definition
Is a limit set by a system administrator that restricts certain aspects of file system usage on modern operating systems.
Term
Soft Quotas
 Definition
will make use of a simple notification through the network that the user is nearing his or her limit.
Term
Hard Quota
 Definition
After notifying the user that he or she is nearing their assigned disk quota, the system will effectively shut the user out once the assigned quota is exceeded.
Term
Hard Quota
 Definition
This type of system management will require the administrator to intervene, either by increasing the disk quota allotted to the user, or by working with the user to archive or eliminate unnecessary files and reduce the user’s files back to a level below the quota. Strictly enforce.
Term
Soft Quotas
 Definition
However, this approach does not include any follow-up action, other than also notifying the administrator that a given user is nearing their assigned disk quota.
Term
What is a boot loader?
 Definition
A small program that loads the operating system into the computer’s memory when the system is booted and also starts the operating system.
Term
Faster, better for single OS machines
 Definition
LILO
Term
Redhat default bootloader, better when multi OS machines
 Definition
GRUB
Term
How grub entries are crafted?
 Definition
GRUB supports a powerful command-line interface as well as facilities for editing configuration file entries on the fly.
Term
To enter command-line mode, type _ from the GRUB boot image
 Definition
c
Term
T/F From the command line you can boot operating systems that aren’t in grub.conf, display system information, and perform rudimentary filesystem testing.
 Definition
True.
Term
Where is GRUB2 configuration file
 Definition
The GRUB2 configuration file (located in /boot/grub/grub.conf), GRUB configuration file is located in ''/boot/grub/menu.lst”
Term
GRUB is created by?
 Definition
Redhat
Term
What is the boot process to get Linux running on a system?
 Definition
• System startup (test hardware with POST) – BIOS/ Boot monitor
• Stage 1 bootloader – Master Boot Record
• Stage 2 bootloader – LILO, GRUB,…
• Kernel – Linux
• Init – User space
Term
When an x86 computer is booted, the processor looks at the end of ?
 Definition
system memory for the BIOS (Basic Input/Output System) and runs it
Term
The ____ is written into permanent read-only memory and is always available for use.
 Definition
BIOS program
Term
The BIOS provides the _______ and controls the first step of the boot process.
 Definition
lowest level interface to peripheral devices
Term
Looks for and checks peripherals, and then looks for a drive to use to boot the system.
 Definition
The BIOS tests the system
Term
When Booting it checks for what to boot from before hard drive
 Definition
CD ROM or Floppy
Term
The order of the drives used for booting is usually controlled by ?
 Definition
BIOS Settings
Term
Once Linux is installed on the hard drive of a system, the BIOS looks for a ____ starting at the first sector on the first hard drive, loads its contents into memory, then passes control to it.
 Definition
Master Boot Record (MBR)
Term
This MBR contains instructions on how to load the ___ , using a ___________
 Definition
GRUB (or LILO) boot-loader, pre-selected operating system.
Term
The MBR then loads the ___, which takes over the process (if the boot-loader is installed in the MBR)
 Definition
boot-loader,
Term
Once GRUB has received the correct instructions for the operating system to start, either from its command line or configuration file......
 Definition
it finds the necessary boot file and hands off control of the machine to that operating system
Term
What is initrd
 Definition
The initial RAM disk (initrd) is an initial root file system that is mounted prior to when the real root file system is available.
Term
The ____ is bound to the kernel and loaded as part of the kernel boot procedure.
 Definition
initrd
Term
The kernel then mounts this ____ as part of the two-stage boot process to load the modules to make the real file systems available and get at the real root file system
 Definition
initrd
Term
Whyt is intitRD
 Definition
It is needed to load into memory some required modules necessary to boot. Eg: SCSI driver or file system driver.
Term
Contains only whatever is necessary to boot some particular computer, such as ATA, SCSI and filesystem kernel modules. These typically embed the location and type of the root file system.
 Definition
initrd image
Term
a file that has information on which runlevel to start the system at and lists the processes to be run on each runlevel.
 Definition
inittab
Term
(# that corresponds to the runlevel number) directory structure the order is defined in which the services start.
 Definition
rc#.d
Term
is the part of an operating system that is responsible for loading programs, one of the essential stages in the process of starting a program
 Definition
loader
Term
the core or key component of the operating system, consists of many kernel subsystems like process management, memory management, file management, device management and network management.
 Definition
kernel
Term
contains the interfaces to the most important library functions.
 Definition
modules
Term
directory where symbolic links that point to master initscripts are found
 Definition
init.d
Term
to power up the machine.
 Definition
startup
Term
a system configuration file that lists all available disks and disk partitions, and indicates how they are to be initialized or otherwise integrated into the overall system’s file system.
 Definition
fstab
Term
is where many of the files that control the system configuration are stored. This sextion lists these files and many of the optional values in the files used to make system changes
 Definition
/etc/sysconfig scripts
Term
What are kernel modules?
 Definition
pieces of code that can be loaded and unloaded into the kernel upon demand (like hardware drivers) to extend the functionality of the kernel without the need to reboot the system.
Term
How do you list Kernel Modules
 Definition
sudo /sbin/lsmod
Term
How do you add kernel moduel
 Definition
sudo insmod /path/to/snarf.ko
Term
How do you remove kernel Modules
 Definition
Rmmod tries to unload a set of modules from the kernel, with the restriction that they are not in use and that they are not referred to by modules.
Term
What are system runlevels?
 Definition
Runlevels defines the state of the machine after boot.
Term
probably the most important daemon, since is the first process to run after the system boots and it always have a PID of 1.
 Definition
init
Term
Name them and what typically occurs in those runlevels:
 Definition
 Runlevel 0: Halt System (To shutdown the system)
 Runlevel 1: Single user mode
 Runlevel 2: Basic multi user mode without NFS
 Runlevel 3: Full multi user mode (text based)
 Runlevel 4: Unused
 Runlevel 5: Multi user mode with Graphical User Interface
 Runlevel 6: Reboot System
Term
Runlevels __& ___ are generally used for debugging purposed only,
 Definition
Runlevels 1 and 2
Term
Most desktop Linux distributions boot into runlevel _, which starts up the Graphical Login Prompt.
 Definition
5
Term
Most servers boot into runlevel _, which starts the text based login prompt.
 Definition
3
Term
How do you change runlevels (init, halt, reboot, shutdown)?
 Definition
Linux runlevels can be changed using the init tool.
Term
To switch from text based operations to the Graphical Interface,
 Definition
‘telinit 5’ in the root prompt
Term
The ____ file has information on which runlevel to start the system at and lists the processors to be run at each runlevel.
 Definition
“/etc/inittab”
Term
telinit 3
 Definition
this will force init to go to run level 3
Term
telinit -q
 Definition
will cause init to reread the /etc/inittab
Term
directory where symbolic links that point to master initscripts are found
 Definition
/etc/init.d
Term
directory structure the order is defined in which the services start.
 Definition
/etc/rc#.d
Term
The chkconfig or update-rc#.d utilities, when installed on your system, provide a simple command-line tool for maintaining the /etc/init.d directory hierarchy.
 Definition
chkconfig
Term
is a plain ASCII file providing a mapping between friendly textual names for internet services, and their underlying assigned port numbers and protocol types.
 Definition
Service
Term
What is a linux system process?
 Definition
In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity.
Term
How does the linux kernel track processes?
 Definition
Tracks process management, memory management, file management, device management and network management.
Term
The system administrator’s main tool for monitoring processes.
 Definition
ps
Term
You can use it to show the PID (Process ID), UID (User ID), priority, and control terminal of processes.
 Definition
ps
Term
Options to list all running processes on a Linux/Gnu system
 Definition
ps –aux
Term
The ___ command provides a regularly updated summary of active processes and their use of resources
 Definition
top
Term
home directory of the superuser
 Definition
/root
Term
kernel and files needed to load the kernel
 Definition
/boot
Term
critical startup and configuration files
 Definition
/etc
Term
various system log files
 Definition
/var/log
Term
holds those files and commands used by the system;
this directory breaks down into several subdirectories.
 Definition
/usr
Term
libraries and parts of the C compiler
 Definition
/lib
Term
What is the benefit of automated updates?
 Definition
System security vulnerabilities are patches and software is up to date.
Term
What are the dangers of automated updates?
 Definition
Automated updates can create conflicts between programs, unresolved dependencies, and broken systems. No control about what it is installed.
Term
What does yum install and yum update do?
 Definition
This is a metapackage manager based on RPM and the official package manager for Red Hat Linux.
Term
Yum install
 Definition
Downloads and install the most recent version of packages
Term
Yum update
 Definition
It will update every currently installed package leaving obsolete package in the system
Term
Yum upgrade
 Definition
it will update every currently installed package removing and replacing packages marked as obsolete by developers.
Term
rpm
 Definition
Easier to install using a package manager. Binary. Not configurable
Term
tarballs
 Definition
Harder to install. They should be decompressed and compiled before being able to run them
Term
source rpm(s)
 Definition
They contain the source code. They should be compiled before installing, more configurable.
Term
Reads multiple files or directories and packages them into ne files, often a tape file.
 Definition
tar
Term
useful way to back up any files whose near-term recovery you anticipate.
 Definition
tar
Term
useful for moving directory trees from place to place, especially if you are copying files as root.
 Definition
tar
Term
creates
 Definition
tar -cf
Term
extracts
 Definition
tar -xf
Term
preserves ownership and time information
 Definition
tar --atime-preserve
Term
lets you specify a “blocking factor”
 Definition
tar -b
Term
reduces the size of the named files using Lempel-Ziv coding.
 Definition
gzip
Term
gzip <filename>
 Definition
Compress <filename>
Term
Where does the httpd config file 'live' by default?
 Definition
/etc/httpd/httpd.conf
Term
How can you start and stop Apache (httpd) without shutting the system down?
 Definition
Service httpd start
Service httpd stop
Term
kill -KILL <pid>
 Definition
guarantees superkill
Term
kill -9 <pid>
 Definition
signal number on how to terminate process
Term
kill -STOP <pid>
 Definition
stops the process
Term
kill -CONT <pid>
 Definition
lets the process to continue
Term
Steps involved in building a linux kernel
 Definition
Step 1 make dep (Building Dependencies)
Step 2 make bzImage (Building the “big compressed
image” of the kernel)
Step 3 make modules (Building modules)
Step 4 make modules_install (Installing modules)
Term
How can kernel modules be configured to be used by the kernel?
 Definition
Y’: feature will be compiled into the kernel images
• ‘M’: feature will be compiled as a module
• ‘N’: feature will not be compiled
Term
What is the role of the system administrator
 Definition
o Security
o System
o Users
o Applications
o Response
o Reliability
o Execute policies
Term
Unix Access-Control/Security model
 Definition
o User accounts: root, user, special accounts
o Groups
o permissions.
Term
What is selinux
 Definition
Security-enhanced Linux (SELinux) is an implementation of a mandatory access control mechanism.
Term
How can you assume root privileges
 Definition
The sudo command stands for "superuser do".
Term
Replace user with the name of the account which you'd like to run the command as, and command with the command you need to run as another user.
 Definition
su user -c command
Term
Replace user with the name of the account which you'd like to run the commands as.
 Definition
su user
Term
Why is it a bad idea to use root account for regular non-maintenance tasks?
 Definition
Because root can do anything to the system, and it could unintentionally damage the system.
Term
What files are involved in user creation?
 Definition
/etc/passwd
/etc/shadow
/etc/group
Term
file stores essential information, which is required during login i.e. user account information.
 Definition
/etc/passwd
Term
file stores actual password in encrypted format for user’s account with additional properties related to user password i.e. it stores secure user account information.
 Definition
/etc/shadow
Term
is a text file which defines the groups to which users belong under Linux and Unix operating system.
 Definition
/etc/group
Term
What are the 'critical' fields that define a user in the /etc/passwd file?
 Definition
1. Username: It is used when user logs in.
2. Password: An x character indicated that encrypted password is stored in /etc/shadow file.
3. User ID (UID): Each user must be assigned a user ID (UID).
4. Group ID (GID): The primary group ID (stored in /etc/group file)
5. User ID Info: The comment field.
6. Home directory: The absolute path to the directory the user will be in when they log in.
7. Command/shell: The absolute path of a command or shell (/bin/bash).
Term
What file is the user password stored (on CentOS distribution)?
 Definition
• /etc/shadow: file stores actual password in encrypted format for user’s account with additional properties related to user password i.e. it stores secure user account information.
• /etc/group: is a text file, which defines the groups to which users belong under Linux and Unix operating system. Under Unix / Linux multiple users can be categorized into groups.
• /etc/gshadow: is a file readable only by the root user and contains an
encrypted password for each group, as well as group membership and administrator information.
Term
file stores actual password in encrypted format for user’s account with additional properties related to user password i.e. it stores secure user account information.
 Definition
/etc/shadow
Term
is a text file, which defines the groups to which users belong under Linux and Unix operating system. Under Unix / Linux multiple users can be categorized into groups.
 Definition
/etc/group
Term
is a file readable only by the root user and contains an
encrypted password for each group, as well as group membership and administrator information.
 Definition
/etc/gshadow
Term
the command is most often used to terminate a process.
 Definition
kill
Term
gets file status
 Definition
stat
Term
·          prints real and effective UIDs and GIDs
 Definition
id
Term
prints effective userid
 Definition
whoami
Term
prints the groups a user in in
 Definition
groups
Term
prints the user names of users currently logged in to the current host
 Definition
users
Term
shows who is logged on
 Definition
who
Term
prints or sets the system date and time
 Definition
date
Term
prints system information
 Definition
uname
Term
shows or sets the system’s host name
 Definition
hostname
Term
displays top CPU processes
 Definition
top
Term
estimates file space usage
 Definition
du
Term
reports filesystem disk space usage
 Definition
df
Term
runs a program with modified scheduling priority
 Definition
nice
Term
alters priority of running processes
 Definition
renice
Term
builds a filesystem
 Definition
mkfs
Term
sets up a swap area
 Definition
mkswap
Term
checks and repairs a filesystem
 Definition
fsck
Term
partitions table manipulator
 Definition
fdisk
Term
to mount a filesystem
 Definition
mount
Term
to detached filesystems
 Definition
umount
Term
What information does the /etc/fstab file contain (mount point, filesystem type, mount options)?
 Definition
The file lists all available disks and disk partitions, and indicates how
they are to be initialized or otherwise integrated into the overall system’s file system.
Term
What directory on the filesystem doesn't actually have files on the hard drive?
 Definition
/proc
Term
Log files live in: /var/log, what sort of messages these do /var/log/messages and /var/log/dmesg
 Definition
/var/log/messages
Term
It logs main system events such as user logins, FTP connections, and superuser logins, etc.
 Definition
/var/log/messages
Term
It logs kernel messages
 Definition
/var/log/dmesg
Term
provides two system utilities which provide support for system
logging and kernel message trapping. Support of both internet and unix domain
sockets enables this utility package to support both local and remote logging.
 Definition
syslogd
Term
is a system daemon which intercepts and logs Linux kernel messages
 Definition
klogd
Term
is a standard for logging program messages.
 Definition
syslog
Term
What are syslog facilities, name some?
 Definition
auth, authpriv, daemon, cron, ftp, lpr, kern, mail, news, syslog, user, uucp, local0, …, local7
Term
What are syslog priorities?
 Definition
Emergency, Alert, Critical, Error, Warning, Notice, Info or Debug
Term
is designed to ease administration of systems that generate large numbers of log files. It allows automatic rotation, compression, removal, and mailing of log files.
 Definition
logrotate
Term
time-based job scheduler.
 Definition
Cron
Term
Enables users to schedule jobs to run periodically at certain times or dates.
 Definition
Cron
Term
It is commonly used to automate system maintenance of administration, though its general-purpose nature means that it can be used for other purposes, such as connecting to the Internet and downloading email.
 Definition
Cron
Term
Where is cron configured?
 Definition
/var/spool/cron
Term
Where does any output go by default?
 Definition
/etc/contab
Term
What is benchmarking?
 Definition
Benchmarking means measuring the speed with which a computer
system will execute a computing task, in a way that will allow
comparisons between different had/software combinations.
Term
. Dhrystone measures what?
 Definition
Dhrystone is a synthetic computing benchmark program intended to be
representative of system (integer) programming.
Term
CGI
 Definition
CGI stands for Common Gateway Interface.
Term
defines how webserver software can delegate the generation of webpages to a consoled application
 Definition
CGI
Term
a high-level, general-purpose, interpreted, dynamic programming
language.
 Definition
Perl
Term
originally was developed as a general purpose Unix
scripting language to make report processing easier.
 Definition
Perl
Term
Perl - name a use for it
 Definition
Provides powerful text processing facilities without the arbitrary data
length limits of many contemporary Unix tools, facilitating easy
manipulation of text files.
Term
protocol used for communicating data across a packet-switched internetwork using the Internet Protocol Suite, also referred to as TCP/IP. IP is the primary protocol in the Internet
 Definition
IP
Term
is one of the core protocols of the Internet Protocol Suite.
 Definition
ICMP
Term
It is chiefly used by networked computers’ operating systems to sent error messages-indicaing, for instance, that a requested service is not available or that a host or router could not be reached.
 Definition
ICMP
Term
is a computer networking protocol for determining a network host’s link layer or hardware address when only is Internet Layer (IP) or Network Layer address is known.
 Definition
ARP
Term
is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet.
 Definition
UDP
Term
is a standard network protocol used to copy a file from one host to another over a TCP/IP-based network, such as the Internet.
 Definition
FTP
Term
built on a client-server architecture and utilizes separate control and data connections between the client and server applications, which solves the problem of different end host configurations.
 Definition
FTP
Term
is an Application Layer protocol for distributed, collaborative, hypermedia information systems.
 Definition
HTTP
Term
defines a standardized pack format for delivering audio and video over the Internet.
 Definition
RTP
Term
is a sister protocol of the Real-time Transport Protocol.
 Definition
RTCP
Term
an application protocol for querying and modifying data using directory services running over TCP/IP.
 Definition
LDAP
Term
an IETF-defined signaling protocol, widely used for controlling multimedia communication sessions such as voice and video calls over Internet Protocol (IP).
 Definition
SIP
Term
a general term for a family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packet-switching networks
 Definition
VoIP
Term
used extensively in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications and web-based push to talk features.
 Definition
RTP
Term
Class A
 Definition
0.0.0.0 - 127.255.255.255
Term
Class B
 Definition
128.0.0.0 - 191.255.255.255
Term
Class C
 Definition
192.0.0.0 - 223.255.255.255
Term
Class D
 Definition
224.0.0.0 - 239.255.255.255
Term
Class E
 Definition
240.0.0.0 - 255.255.255.255
Term
ifconfig - what/ how is it used?
 Definition
a system administration utility in Unix-like operating systems to configure, control, and query TCP/IP network interface parameters from a command line interface (CLI) or in system configuration scripts.
Term
View the network settings on the first Ethernet adapter installed in the computer.
 Definition
ifconfig eth0
Term
Display info on all network interfaces on server, active or inactive.
 Definition
ifconfig -a
Term
If eth0 exists would take it down causing it cannot send or receive any information.
 Definition
ifconfig eth0 down
Term
If eth0 exists and in the down state would return it back to the up state allowing to to send and receive information.
 Definition
ifconfig eth0 up
Term
Assign eth0 with the above values for IP, netmask and broadcast address.
 Definition
ifconfig eth0 192.168.1.102 netmask 255.255.255.0 broadcast 192.168.1.255
Term
a computer network administration utility used to test the reachability of a host on an Internet Protocol (IP) network and to measure the round-trip time for messages sent from the originating host to a destination computer.
 Definition
ping
Term
a command used to view and manipulate the TCP/IP routing table in both Unix-like and Windows operating systems.
 Definition
Route
Term
is a computer network diagnostic tool for displaying the route (path) and measuring transit delays of packets across an Internet Protocol (IP) network.
 Definition
Traceroute
Term
– is a computer network diagnostic tool for displaying the route (path) and measuring transit delays of packets across an Internet Protocol (IP) network.
 Definition
Arp
Term
This syntax allows an administrator to make a new manual ARP cache table entry that maps the given host name to the specified hardware address
 Definition
ARP Cache Table Entry Addition
Term
This command removes the specified cache entry from the table. Some implementations allow the addition of another parameter to specify that all entries should be removed from the cache
 Definition
ARP Cache Table Entry Deletion
Term
an application-specific or process-specific software construct serving as a communications endpoint.
 Definition
port
Term
common name for the daemon that allows a server to provide a DHCP service to a network.
 Definition
DHCPD
Term
SYN, SYN, SYNACK, ACK
 Definition
named
Term
-zone master versus slave
- zone configuration
 Definition
Firewall
Term
FTP Ports
 Definition
Powerful, web-based mailing list manage, The GNU Mailing List Manager, which manages email discussion lists much like Majordomo and Smartmail.
Term
mailman - provides what functionality?
 Definition
Powerful, web-based mailing list manage, The GNU Mailing List Manager, which manages email discussion lists much like Majordomo and Smartmail.
Term
ftp what does it do?
 Definition
Internet file transfer program.
Term
protocol, allowing a user on a client computer to access files over a network in a manner similar to how local storage is accessed.
 Definition
Internet file transfer program.
Term
is a service that runs on nodes on the Internet for the purpose of mapping on ONC RPC program number to the network address of the server that listens for the program number.
 Definition
portmap
Term
samba what is it
 Definition
is an Open Source/Free Software suite that provides seamless file and printing services to SMB/CIFS clients.
Term
dmidecode
 Definition
a tool for dumping a computer's DMI (some say SMBIOS ) table contents in a human-readable format.
Term
Read memory from device FILE (default: /dev/mem)
 Definition
-d, --dev-mem FILE
Term
Be less verbose Unknown, inactive and OEM -specific entries are not displayed. Meta-data and handle references are hidden. Mutually exclusive with --dump.
 Definition
-q, --quiet
Term
Only display the value of the DMI string identified by KEYWORD.
 Definition
-s, --string KEYWORD
Term
reports information about processes, memory, paging, block IO, traps, and cpu activity.
 Definition
vmstat
Term
list open files
 Definition
lsof
Term
allows you to see the attributes of VolumeGroupName (or all volume groups if none is given) with it's physical and logical volumes and their sizes etc.
 Definition
vgdisplay
Term
allows you to see the attributes of one or more physical volumes like size, physical extent size, space used for the volume group descriptor area and so on.
 Definition
pvdisplay
Term
allows you to see the attributes of a logical volume like size, read/write status, snapshot information etc
 Definition
lvdisplay
Term
opens a connection to an LDAP server, binds, and performs a search using specified parameters
 Definition
ldapsearch
Term
opens a connection to an LDAP server, binds, and deletes one or more entries
 Definition
ldapdelete
Term
used to watch system processes over time
 Definition
watch
Term
is a GNU command-line tool that runs the specified command repeatedly and displays the output on stdout so you can watch it change over time.
 Definition
watch
Term
command streamlines the process of starting an X session.
 Definition
Startx
Term
download a file from a website or online source
 Definition
Wget
Term
writes to the standard output information about active interprocess communication facilities
 Definition
Ipcs
Term
Often the simplest and quickest way to find the locations of files and directories
 Definition
Locate
Term
changes the startup information for the specified service. (Either On or Off)
 Definition
Chkconfig
Term
Plain ASCII file providing a mapping between friendly textual names for internet services, and their underlying assigned port numbers and protocol types
 Definition
Service
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