Linux Chapter 13

DHCP

-Protocol used to take a pool of IP addresses and assign or lease them to a group of computers for a certain amount of time.

ipv4 dchp configuration file

/etc/dhcp/dhcpd.conf

ipv6 dhcp configurtion file

/etc/dhcp/dhcpd6.conf

ntpd config directory

/etc/ntpd.conf

document root directory

/var/www/html

DHCP Lease Process

1. client sends a DHCPDISCOVER packet to all hosts in the network 2. Server send a DHCPOFFER packet that contains potential ip configuration 3. The client accepts the offer by sending a DHCPREQUEST packet to the server 4. the server sends to the client an acknowledgement indicating the amount if time the client can use the ip configuration

hwclock

A command that can be used to view and modify the system clock within the computer Bios

tzselect

A command that can change the time-zone of a Linux server

chronyc command

A command that can query the NTP server or client as well as synchronize the system time with an NTP server.

ntpq

A command that can query the state of the NTP server or client

ntpdate

A command that can view the current system time as well as synchronize the system time with an NTP server

NIS clients

A computer in an NIS domain that receives its configuration from an NIS master server or slave server

NIS slave server

A computer in the NIS domain that receives a read-only copy of all NIS maps from an NIS server.

NIS domain

A group of computers within the same NIS configuration

Mail user agent

A mail client application that a user interacts with.

Apache Web Server

A popular Web server that runs on most operating systems, particularly Windows and Linux.

DHCP server

A server running the Dynamic Host Configuration Protocol (DHCP) service. This server allocates IP addresses to DHCP client computers. (13)

Structured Query Language

A special programming language used to store and access the data in databases.

NIS map

A system configuration that is shared by the computers within and NIS domain

samba server

A system that shares a resource for Samba clients. daemon that imitates smb so you can communicate with windows devices

zone file

A text file associated with a DNS zone that contains resource records identifying domains and their IP addresses.

mail delivery agent

An e-mail server program that receives sent messages and delivers them to their proper destination mailbox.

testparm

Checks the smb.conf config file for internal correctness.

Network File System

Client-server application protocol used for UNIX systems. protocol that supports file sharing between two different file systems

SQL servers

Database server programs that allow users to access and update the data stored within a database

Network Time Protocol

Designed to simplify the setting of time and date information on computers across the internet using UDP port 123

Stratum 1

Devices that obtain their time directly from Stratum 0 devices

Stratum 2

Devices that obtain their time directly from Stratum 1 devices

File Transfer Protocol

Most common system for transferring files over the Internet, often used for uploading websites

ntpd

NTP daemon

mget

Short for multiple get, mget is a command used in an FTP session to download multiple fines at once from that computer.

mput

Short for multiple put, mput is an FTP command used to upload multiple files or multiple wildcards at once when connected to a remote computer.

SMTP

Simple Mail Transfer Protocol

if time on a server is not synchronized

Stop the ntpd and run the ntpdate command. after time is synced, restart the ntpd.

NIS master server

The computer in and NIS domain that contains the master copy of all of NIS maps

jitter

The difference between time measurements from several different NTP servers.

document root

The directory on a web server that stores web content for distribution to Web Browsers

Strata

The levels within an NTP hierarchy that describe the relative position of a server to an original time source such as an atomic clock

Postfix

The most common email daemon used on a modern Linux system. accepts emails on port 25

PostgreSQL utility

The program used to perform most database management ona PostgreSQL server

Server Message Blocks

The protocol that Windows computers use to format file and printer sharing traffic on TCP/IP networks

ftp command

a command that opens a connection that allows the transfer of files to and from a computer

dumpleases command

a command used to obtain current dhcp leases from BusyBox daemon

Domain Name Service

a hierarchical namespace used to identify computers on large TCP/IP networks such as the internet

Zone

a portion of the Domain Name Space that is administered by one or more DNS servers

Lightweight Directory Access Protocol

a software protocol for enabling anyone to locate organizations, individuals, and other resources such as files and devices in a network, whether on the public Internet or on a corporate intranet.

restrict 127.0.01

allows the local client to query the NTP daemon for time information with no restrictions.

PostgreSQL

an open source relational database management system ( DBMS ) developed by a worldwide team of volunteers

Network Information Service

can use to coordinate common configuration files, such as /etc/passwd and /etc/hosts, across several Linux computers with an organization. does not work on windows

smbclient command

command to connect to a samba server

curl command

command used in a BASH prompt to obtain a web page

psql command

command used to start the PostgreSQl utility

Mail Transfer Agent

delivers messsage to the destination server using smtp

DHCP daemon

dhcpd

Stratum 0

highest in the NTP hierarchy, consists of atomic devices or GPS clocks

chronyd

sometimes used in place of ntpd because of faster response time and is backwards compatible.

vsftpd

stand alone daemon for an FTP server

offset

the difference in time between computers that use the NTP protocol

BusyBox DHCP daemon

udhcp

configuration of Samba

useradd=mary passwd mary smbpasswd -a mary