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Linux Essentials Certification 2017 > Linux Operating System > Flashcards

Flashcards in Linux Operating System Deck (44):
1

What is the first process started by Kernal called?

init

2

What are processes launched by init called?

child processes

3

where is the init process typically stored?

/sbin/init

4

PID

process ID - lots of processes rely on PID

5

PPID

Parent process id

6

what is generally used to search for processes?

top and ps

7

free command

frees memory from processes

8

ps -u user --forest does what

shows a tree of processes by the user user

9

ps aux is?

good and adds a user and just makes it look nice? idk 5 this

10

/lib

dynamic libraries and also supports static files needed for the boot process.

11

/usr/lib

also dynamic libraries and support static files for the /usr/bin and /usr/sbin

12

/var/log

logging!

13

/etc

usually contain teh configuration files for all the programs that run on linux/unix

14

Where are deamons' config files stored

in a subdir of /etc

15

7 layers of internet communcation?

7Application
6Presentation
5Session
4Transport
3Network
2Data link
1Physical

16

1Physical

literally transmits electrical signals between the hosts. It's the network card connected to a wire

17

2Data Link

defines rules for accessing physical layer. Specifies how to verify data recieved from the physical layer.

18

3Network

Enables routing of data, spefices how to recognize addresses and the next network point to send a node.

Internet and ICMP operate on this level

19

4Transport

sending host's 4 recieves data and divides it into packets. The receiving provides error checking and unpacks packets and assembles the data.

20

5Session

Responsible for establishing and maintaining a connection between two machienes

21

6Presentation

Ensures information passingthroughout all layers is formatted corretly for 7

22

7Application

provides applications for a way to access networiking

23

TCP

a protocal that ensures data exchanged between two network hosts is exchanged reliably

24

what two protocals are used with IP

TCP and UDP

25

ICMP stands for?

Internet Control Message Protocol.

26

ICMP is used for what?

Testing connections between hosts

27

what layers are ports accessed at

The 4Transport layer

28

20 21

FTP

29

23

Telnet

30

25

SMTP

31

80

HTTP

32

443

HTTPS

33

110

POP3

34

137 138 139

NetBIOS

35

Well-know ports

0-1023
For well established services

36

Registered ports

1024-49151
Special Implementation
Orgs can apply for a reg port number to be assigned to their service

37

Dynamic Ports

49152-65535
Available for any use by any network service
usually used for temporarilly establish connections between two applications.

38

what layer does the MAC address oprate

2Data Link.
MAC address is hardcoded on the network board and cannot be changed.

39

If the last octet in an IP address is 0, what does that mean?

it is the network address. Eg 161.161.161.0. A host cannot use that IP address

40

what is the last octet of 255 reserved for

broadcast addresses.

41

Class A private IP range?

10.0.0.0 - 10.255.255.255

42

Class B private IP range?

172.16.0.0 - 172.31.255.255

43

Class C private IP range?

192.168.0.0 - 192.168.255.255

44

what are the two parts of an ipv4 addr?

Network and node(host)
network is first 3, node is final one