TCP/IP Flashcards

1
Q

Co obsahuje sietova vrstva v TCP/IP?

A
protokol IP
prenos IP paketov medzi dvoma zariadeniami
fragmentacia paketov
adresy - 4B čísla
cast adresy - siet, druha konkretny uzol
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2
Q

Aky je protokol IP?

A

Connection less unreliable

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3
Q

Ake pozname triedy IP adries?

A
  1. x.x.x - 126.x.x.x A (7 bit siet, 24 bit host)
  2. x.x.x - 191.x.x.x B (14bit siet, 16bit host)
  3. x.x.x - 223.x.x.x C (21bit siet, 8 bit host)
  4. x.x.x. 239.x.x.x D
  5. x.x.x - 255.x.x.x E vyhradené
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4
Q

Na akých adresách prebieha multicast?

A

224.x.x.x. 239.x.x.x D

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5
Q

Co je maska a co urcuje?

A

urcuje, ktore bity tvoria adresu siete
suvisly blok 1 suvisly blok 0
teda napr 255.255.255.128 - 25bitov siet

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6
Q

Aka je adresa siete? Teda identifikator

A

0.0.0.0

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7
Q

Aka je adresa pre broadcast?

A

Same 1, teda 255.255.255.255

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8
Q

na akej IP pocuva lokalny pocitac?

A

127.0.0.0/255.0.0.0

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9
Q

ake adresy su pre sukromne siete?

A

192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8

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10
Q

Aka je adresa pre broadcast na lokalnej sieti?

A

255.255.255.255

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11
Q

Ake su adresy pre 158.195.16.0/255.255.254.0?

A

adresy 158.195.16.1 - 158.195.17.254

broadcast 158.195.17.255

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12
Q

co obsahuje IP paket? A opis ho aj jeho velkost

A

hlavicka (20 az 60B)
maximalna velkost 65536 B
umoznuje fragmentaciu paketov

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13
Q

Co obsahuje hlavicka IP paketu?

A
adresu odosielatela a ciela
dlzka paketu
transportny protokol
time-to-live
kontrolny sucet
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14
Q

Co je to router?

A

Pocitac/HW s aspon 2 sietovymi interfaceami/linkami

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15
Q

Co je routovacia tabulka?

A

Obsahuje adresu, masku, dalsi router a sietovy interface (viac riadkov)

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16
Q

Aku polozku vyberam v routovacej tabulke?

A

Najspecifickejsiu, s najvacsou maskou kde to sedi

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17
Q

Opis riadok v routovacej tabulke

158.195.18.0/255.255.255.0 - eth0

A

Ak mam adresu 158.195.18.x, tak to posielam na sietovu kartu eth0

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18
Q

Opis riadok v routovacej tabulke

0.0.0.0/0.0.0.0 158.195.18.209 eth0

A

Hocico co neprejde pred tym posielam cez eth0 na 158.195.18.209

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19
Q

Co riesi ARP?

A

Preklad IP adresy na fyzicku

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20
Q

Na akej vrstve sa nachadza ARP?

A

Na linkovej

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21
Q

Co je skratka ARP?

A

Address resolution protocol

22
Q

Ako prebieha preklad ARP IP na fyz adresu?

A
  1. vyšle broadcast “Kto má IP a.b.c.d?”
  2. zariadenie s IP a.b.c.d odpovie:
    “IP a.b.c.d má zariadenie x:y:z:p:q:s”
23
Q

Aky je broadcast cez ethernet?

A

FF:FF:FF:FF:FF:FF

24
Q

Aky je multicast cez ethernet?

A

01:00:5E:X:Y:Z kde X:Y:Z je spodnych 23 bitov z IP adresy

25
Q

Co riesi ICMP?

A

diagnostiku a spracovanie chyb, napr. ping, destination unreachable, redirect, Time-to-live exceeded a pod.

26
Q

Co je chyba redirect?

A

router posunul paket do rovnakej fyzickej siete z akej dosiel, teda nebolo treba ist cez router

27
Q

Co je skratka ICMP?

A

Internet Control Message Protocol

28
Q

Ake pozname protokoly v TCP/IP? a ich connection a spolahlivost?

A

TCP (Transmission Control Protocol) - connection oriented, reliable
UDP (User Datagram Protocol) - connection-less unreliable

29
Q

Na akej vrstve sa nachadzaju protokoly TCP a UDP?

A

na transportnej

30
Q

Co navyse v adrese obsahuju protokoly TCP a UDP?

A

Cislo portu

31
Q

Co obsahuje hlavicka UDP?

A

zdrojovy a cielovy port, velkost, kontrolny sucet

32
Q

Co obsahuje hlavicka TCP?

A

zdrojov a cielovy port, sekvencne cislo, potvrdzovacie cislo, velkost okna, priznaky, kontrolny sucet a pod

33
Q

Preco je TCP reliable?

A

Kazdy paket sa potvrdzuje, ak sa nepotvrdi tak sa paket posle znova

34
Q

Co je sekvencne cislo?

A

Určuje poradie prvého bajtu segmentu v prúde dát aplikačnej vrstvy. Číslovanie prúdu dát sa začína náhodným číslom a po dosiahnutí maximálnej hodnoty 2^(32)-1 pokračuje opäť od nuly.

35
Q

Ako sa vytvara spojenie v TCP? Ake priznaky sa posielaju?

A

SYN
SYN ACK
ACK

36
Q

Ako sa ukoncuje spojenie v TCP? Ake priznaky sa posielaju?

A

FIN ACK
FIN ACK
ACK

37
Q

Na co sluzi NAT?

A

umoznuje komunikaciu zo siete so sukromnymi adresami

38
Q

Co je skratka NAT?

A

Network Address Translation

39
Q

Co je source NAT? SNAT

A

zdroj spojenia ma sukromnu adresu

40
Q

Co je destination NAT? DNAT

A

ciel spojenia ma sukromnu adresu

41
Q

Co si uchovava router v NAT?

A

tabulku spojeni:

  • adresa a port zdroja a ciela
  • protokol
  • prelozena adresa a port
42
Q

Co robi router v NAT pri odoslani prveho paketu von?

A

1: prepise adresu zdroja na prelozenu
2. prepise port zdroja na vlastny
3. zapise spojenie do tabulky

43
Q

Co robit router v NAT pri poslanie dalsieho paketu von?

A

najde spojenie v tabulke a prepise adresu a port zdroja podla tabulky

44
Q

Co robi router v NAT pri prijati paketu zvonku?

A

najde spojenie v tabulke

prepise adresu a port ciela podla tabulky

45
Q

Co robi DNAT router pri prijati paketu zvonka na urcenu verejnu adresu a port?

A

Ak je spojenie v tabulke, prepise ciel podla tabulky

Inak prepise ciel konfiguracie a spojenie zapise do tabulky

46
Q

Co robi DNAT router pri odoslani paketu von?

A

Najde spojenie v tabulke

Prepise zdroj podla tabulky

47
Q

Ako dlho sa da drzat spojenie v tabulke? TCP a UDP?

A

TCP - sledovanie stavu spojenia

UDP - timeout

48
Q

Aky je port HTTP?

A

TCP/80

49
Q

Aky je port telnet?

A

TCP/23

50
Q

Aky je port ssh?

A

TCP/22

51
Q

Aky je port DNS?

A

UDP/53 a TCP/53

52
Q

Kedy ma zmysel pouzit UDP?

A

Napr stremovanie, netreba nam spolahlivost ale potrebujeme len rychlost