Minh ho phn tch gi tin giao thc DHCP II.3.Bt cc gi tin vi
Wireshark : Ta ch quan tm n giao thc DHCP v vy cn phi tin hnh lc cc
gi tin da trn giao thc BOOTP nn ta nhp tn giao thc ny vo ca s
Filter. Cu hi 1 : DHCP s dng giao thc no cho tng vn chuyn ? Kim tra
vi cc gi tin bt c bng Wireshark, ta thy mc Internet Protocal s dng
UDP.
Cu hi 2 : V th thi gian th hin th t ca 4 gi tin DHCP : Client
Server -192.168.109.1/24 DHCP DISCOVER DHCP OFFER DHCP REQUEST DHCP
ACK Port 67 Port 68
Cu hi 3 : ia ch tng Datalink ca my Client l g : Ta s coi a ch
Mac ca my client phn Ethernet II thu c a ch sau: MAC =
00:50:56:c0:00:01 Cu hi 4 : Cc gi tr no trong gi tin DHCP Discover
khc vi gi tin DHCP Request?Hai gi tin ny khc nhau cc gi tr Option
trong Bootstrap Protocol
Hnh : DHCP Discover
Hnh : DHCP RequestCu hi 5 : a ch ngun v ch ca cc gi tin : DHCP
DISCOVER Source IP : 0.0.0.0
Destination IP : DHCP OFFER 255.255.255.255
Source IP : 192.168.109.1
Destination IP : DHCP REQUEST 255.255.255.255
Source IP : 0.0.0.0
Destination IP : DHCP ACK 255.255.255.255
Source IP : 192.168.109.1
Destination IP : 255.255.255.255
Cu hi 6 : Xc nh a ch IP ca my server :a ch ca server s nm trong
gi tin DHCP Offer - IP adress : 192.168.109.1
Cu hi 7 : Xc nh gi tin cha thng tin v a ch IP m server s cp cho
client. a ch ny l bao nhiu? Ta c th thy gi DHCP OFFER m my DHCP
server gi cho client cha cc thng tin v a ch IP ca client a ch IP
Client 192.168.109.16
Cu hi 8 : Gii thch ngha ca trng router v subnetmask trong gi
DHCP Offer
Router c dng ly a ch IP ca router qua client., Subnet mask c s
dng phn chia mt mng ln thnh cc mng nh hn
Cu hi 9 : Xc nh a ch IP m my client yu cu server trong gi tin
DHCP Request l: 192.168.109.16
Cu hi 10 : Gii thch ngha ca lease time. Xc nh lease time trong
trng hp nyLease time l thi gian Client gi mt a ch IP c cp bi DHCP
server. Nu thi gian ht hn th Client v DHCP server li phi m phn t u
xin cp mt a ch IP mi. Trong trng hp ny lease time s nm trong gi tin
DHCP Offer v c thi gian l 8 ngy.
Cu hi 11 : Chc nng ca gi tin DHCP Release l g? Nu gi tin ny b mt
th s nh th no?Chc nng ca gi tin DHCP Release l gii phng a ch IP v
xo bt c thu bao no ang tn ti.Nu gi tin ny b mt th sau a ch IP s vn
c s dng cho n khi ht thi gian lease time. Ti liu tham kho
http://www.wikipedia.org/ http://technet.microsoft.com/
http://www.nhatnghe.com/
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BM MMT&VT Khoa CNTT Trng H KHTN TPHCM Trang 1
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