Chng I
Bi tp ln: DNS trn LINUX
Li cm n!
hon thnh n DNS trn LINUX chng em xin gi li cm n ti thy gio V Xun
Thng tn tnh hng dn cng nh to iu kin v ti liu gip em hon thnh bi tp
ln mn H iu hnh m m tt nht. Em gi li cm n ti nhng kin ng gp tp th TK
10.2 trong thi gian lm bi tp ln cng nh nhng lc bo co trc tip trc
ton th lp.
Bi tp ln hon thnh khng trnh khi nhng thiu st knh mong nhn c nhiu
kin ng gp ca Thy chng em hon thin hn.
Sinh vin: L c Hip
L nh Phong
MC LC5Li m u
8Chng I. GII THIU H THNG TN MIN DNS
8I. Tn min l g ?
9II. H thng tn min l g (Domain Name System)
91. Lch s pht trin h thng tn min
102. Mc ch ca h thng tn min (DNS)
11III. Cu trc ca h thng tn min (DNS)
111. Cu trc c s d liu
132. Cu trc ca tn min
173. My ch qun l tn min (Domain name server-dns)
20Chng II. CU HNH CA NAME SERVER TRONG LINUX
20I.Ci t BIND
21II. Ci t v cu hnh DNS
211 Mt s file cu hnh quan trng.
272. V d cu hnh DNS
33Kt lun
34Ti Liu tham kho
Li nhn xt
Li m u
Ngy nay, vi s pht trin ca khoa hc k thut, my tnh tr nn ph bin vi
mi ngi, n mang li cho con ngi kh nng to ln v lm c nhng cng vic phi
thng : tnh ton nhanh, chnh xc cc php ton phc tp, iu khin t ng v lm
vic theo s lp trnh ca con ngi. My tnh ra i khng ch l cng c gii phng
sc lao ng, h tr ti a trong sn xut m cn l phng tin hc tp, gii tr b
ch trong i sng ca mi ngi. S pht trin ca my tnh cng nh cng ngh thng
tin s mang li nhng thnh tu to ln cho s pht trin kinh t ca t nc. L
phng tin tip cn nhanh nht n cc thnh tu ca khoa hc k thut.Sc mnh ca
my tnh c tng ln nhiu ln khi cc my tnh c kt ni thnh mt mng my tnh. L
c s h tng cho php truyn d liu, trao i thng tin v iu khin t xa, to
nn mt mi trng giao tip, lin kt mi ngi vt qua hn ch v khong cch. Vi
mng my tnh ton cu chng ta c th d dng tip cn vi th gii bn ngoi, tip
cn vi nhng thnh tu khoa hc tin tin nht trn th gii.
Hin nay, ng dng cng ngh thng tin trong sn xut v pht trin kinh t
l mc tiu hng u ca t nc. Mng Internet tr thnh mt lnh vc nghin cu,
pht trin v ng dng ct li ca cng ngh thng tin, bao gm rt nhiu vn t
kin trc, n nguyn l thit k, ci t v m hnh ng dng, cc dch v trn mang.
Mng vin thng ni chung v my tnh v mng my tnh ni ring l cng c khng th
thiu trong hot ng ca b my nh nc, cc doanh nghip, trng hc,... v rt
nhiu cc lnh vc sn xut khc. N ng vai tr nh cu ni trao i thng tin gia
cc chnh ph, cc t chc x hi v gia mi ngi vi nhau.
Vi mt s kt hp rng ri nh vy t ra vn ci g gip con ngi c th truy cp
ti cc trang web d dng tm hiu trao i thng tin t khp mi ni nh vy? l h
thng tn min ( Domain Name System ). Khi cn truy cp n mt web site
trn Internet, bn c th g a ch IP ca site hoc g tn DNS. V cc a ch IP
rt kh nh, nn DNS l mt dch v ng gi. N gip con ngi dng tn truy cp
Internet. My ch DNS c t trn Internet chuyn a ch IP thnh tn min. Nh
cung cp dch v Internet c th thc hin c iu ny hoc kt ni vi my ch DNS
lm chuyn ny. Khi bn nhp tn min trong web browser, yu cu ny c gi n
my ch DNS s cp nh ngha trong cu hnh ca web browser. My ch DNS chuyn
tn thnh a ch IP v tr a ch IP cho h thng, d gip ngi s dng truy cp ti
cc web thng qua tn min nhanh hn.
Trong thi gian hc tp ti trung tm o tao Bch Khoa Npower, di s hng
dn ca cc thy gio chuyn ngnh qun tr mng c bit l thy V Xun Thng, em
chn ti "Dch vu DNS trn LINUX " cho bi tp ln mn hc H iu hnh m m. Mc
ch ca ti l tm hiu k v dch v DNS ci t v cu hnh DNS trn Linux. Vi cc
ti liu thu thp c em hon thnh bi tp ln v dch vu DNS trn LINUX bao gm
nhng kin thc c bn v dch v DNS , cch phn b d liu qun l domain name,
c ch phn gii tn, phn loi Domain Name Server , Resource Record (RR),
ci t v cu hnh dch v DNS.
Chng I. GII THIU H THNG TN MIN DNS
I. Tn min l g ?
Mng my tnh ton cu (Internet) bao gm hng t my tnh ni mng vi nhau,
mi my tnh cn c mt a ch xc nh trn mng. Hin nay a ch dng trn mng l a
ch IP. Mi my tnh c cp pht mt a ch IP v a ch ny l duy nht. a ch IP
hin ang ang c s dng ph bin hin nay l IPv4 c 32 bit chia thnh 4 phn.
Mi phn l 8 bt( tng ng l 1 byte) cch m t tri qua phi. Cc phn cch
nhau bng mt du chm (.) v biu din dng thp phn y l 12 con s. Mi phn l
3 con s. V d mt a ch Internet : 146.123.110.224. V mng my tnh ton
cu hin nay ang pht trin mnh m nn nhu cu v a ch IP ngy cng tng. a ch
IP sp ti c s dng l IPv6 c 128 bit. di gp 4 ln IPv4. Phin bn Ipv4 c
kh nng cung cp 232 = 4 294 967 296 a ch. Phin bn IPv6 c kh nng cung
cp 2128 a ch. Hin nay nc ta ang trin khai th nghim IPv6.
V d: My ch Web Server ang cha website trng HSPKT Hng Yn c a ch l
112.78.2.94 v tn min ca n l utehy.edu.vn. Thc t ngi s dng mun truy
nhp n trang website trng HSPKT Hng Yn th khng cn bit n a ch IP m ch
cn tn min ca n l utehy.edu.vn. Th h thng tn min s tr li li a ch IP
cho my tnh ca bn.
Tn Min l mt danh t dch theo kiu ngha ca tng t mt (Word by Word )
t ting Anh (Domain name). Thc cht tn min l s nhn dng v tr ca mt my
tnh trn mng Internet ni cch khc tn min l tn ca mng li, tn ca cc my
ch trn mng Internet. Mi a ch bng ch ny phi tng ng vi a ch IP ca
n.
II. H thng tn min l g (Domain Name System)
1. Lch s pht trin h thng tn min
Hin nay cc my tnh ni mng ton cu lin lc vi nhau, tm ng trn mng v
nhn din nhau bng a ch IP. V pha ngi s dng c th s dng c cc dch v trn
mng h phi nh c a ch ca cc my ch cung cp dch v ny. Do ngi s dng phi
nh c a ch IP vi dng ch s di nh vy khi ni mng l rt kh khn v th c nhu
cu
mt a ch thn thin, mang tnh gi m v d nh hn cho ngi s dng i km.V t
yu cu hnh thnh h thng tn min.
Ban u vi mng my tnh cn nh ca B quc phng M th ch cn mt tp
HOSTS.txt cha cc thng tin v chuyn i a ch v tn mng. Tuy nhin khi mng
my tnh ngy cng pht trin th vi mt tp HOSTS.txt l khng kh thi.
Tp tin HOSTS.TXT c cc nhc im sau:
Lu lng mng v my ch duy tr tp tin HOSTS.TXT b qu ti do hiu ng c
chai.
Xung t tn: khng th c 2 my tnh c cng tn trong tp tin HOSTS.TXT.
Tuy nhin do tn my khng phn cp v khng c g m bo ngn chn vic to 2 tn
trng nhau v khng c c ch y quyn qun l tp tin nn c nguy c b xung t
tn.
Khng m bo s ton vn: vic duy tr 1 tp tin trn mng ln rt kh khn. V
d nh khi tp tin HOSTS.TXT va cp nht cha kp chuyn n my ch th xa c s
thay i a ch trn mng ri.
Tm li vic s dng tp tin HOSTS.TXT khng ph hp cho mng ln v thiu c
ch phn tn v m rng. Do , dch v DNS ra i nhm khc phc cc nhc im ny.
Thit k cu trc ca dch v DNS ra i nhm khc phc cc nhc im ny. Do vy n
nm 1984 Paul Mockpetris thuc vin USCs Information Sciences
Institute pht trin mt h thng qun l tn min mi ly tn l H thng tn min
Domain Name System v ngy cng pht trin.
Lu : Hin ti trn cc my ch vn s dng c tp tin hosts.txt phn gii tn
my tnh thnh a ch IP (trong Linux l ect/hosts ).2. Mc ch ca h thng
tn min (DNS)
H thng tn min bao gm mt lot cc c s d liu cha a ch IP v cc tn min
tng ng ca n. Mi tn min tng ng vi mt a ch IP c th. H thng tn min trn
mng Internet c nhim v chuyn i tn min sang a ch IP v ngc li t a ch
IP sang tn min. H thng DNS ra i nhm mc ch gip ngi s dng dng mt tn d
nh v mang tnh gi m v ng thi n gip cho h thng Internet d dng s dng
lin lc v ngy cng pht trin.
H thng DNS l h thng s dng c s d liu phn tn v phn cp hnh cy do
vic qun l s d dng hn v cng rt thun tin cho vic chuyn i t tn min
sang a ch IP v ngc li.
Tn min l nhng tn gi nh nh 24h.com.vn hoc go.vn. N thn thin hn a
ch IP gip cho ngi s dng d dng nh v n dng ch m ngi bnh thng c th hiu
v s dng hng ngy.
III. Cu trc ca h thng tn min (DNS)
1. Cu trc c s d liu
C s d liu ca h thng DNS l h thng c s d liu phn tn v phn cp hnh
cy (hierarchical) .
Hnh 1.1 S t chc DNS.
Vi Root server l nh ca cy v sau cc min (domain) c phn nhnh dn
xung di v phn quyn qun l. Khi mt my khch (client) truy vn mt tn min
n s i ln lt t root phn cp xung di n DNS qun l domain cn truy vn. T
chc qun l h thng tn min trn th gii l The Internet Coroperation for
Assigned Names and Numbers (ICANN) .T chc ny qun l mc cao nht ca h
thng tn min (mc root) do n c quyn cp pht cc tn min mc cao nht gi l
Top-Level-Domain.
Cu trc ca d liu c phn cp hnh cy, root qun l ton b s v phn quyn
qun l xung di v tip cc tn min li c chuyn xung cp thp hn (delegale)
xung di.
H thng tn min(DNS) cho php phn chia tn min qun l v n chia h thng
tn min thnh zone v trong zone qun l tn min c phn chia . Cc zone cha
thng tin v min cp thp hn, c kh nng chia thnh cc zone cp thp hn v
phn quyn cho cc DNS server khc qun l.
V d : Zone .vn th do DNS server qun l zone .vn cha thng tin v cc
bn ghi c ui l .vn v c kh nng chuyn quyn qun l (delegate) cc zone cp
thp hn cho cc DNS khc qun l nh .fpt.vn l vng (zone) do fpt qun
l.
H thng c s d liu ca DNS l h thng d liu phn tn hnh cy nh cu trc l
cu trc logic trn mng Internet.
2. Cu trc ca tn min
a)Cch t tn min
-Tn min s c dng : Label.label.label.label
- di ti a ca mt tn min l 255 k t.
-Mi mt label ti a l 63 k t bao gm c du .
-Label phi c bt u bng ch s v ch c cha ch, s, du tr (-) .
b) Cc loi tn min
Cc loi tn min nh:
Com : Tn min ny c dng cho cc t chc thng mi.
Edu : Tn min ny c dng cho cc c quan gio dc, trng hc.
Net : Tn min ny c dng cho cc t chc mng ln.
Gov : Tn min ny c dng cho cc t chc chnh ph.
Org : Tn min ny c dng cho cc t chc khc.
Int : Tn min ny dng cho cc t chc quc t.
Info : Tn min ny dng cho vic phc v thng tin.
Arpa : Tn min ngc.
Mil : Tn min dnh cho cc t chc qun s, quc phng.
M cc nc trn th gii tham gia vo mng internet, cc quc gia ny c qui
nh bng hai ch ci theo tiu chun ISO-3166 V d :
Vit Nam l .vn , Singapo l .sg , M l .us , Anh l .uk , Nht Bn l
.jp, Trung Quc l .cn
V s qu ti ca nhng domain name tn ti, do pht sinh nhng top level
domain mi tn min mi l :
Travel : Tn min dnh cho t chc du lch.
Post : Tn min dnh cho cc t chc bu chnh.
Asts : Nhng t chc lin quan ti ngh thut v kin trc.
Nom : Nhng a ch c nhn v gia nh.
Rec : Nhng t chc c tnh cht gii tr v th thao.
Fim : Nhng t chc kinh doanh thng mi.
Cc tn min di mc root ny c gi l Top Level Domain .
Mi nc c mt top-level domain. V d top-level domain ca Vit Nam l
vn , mi nc khc nhau trn th gii c c ch t chc phn cp domain khc nhau
ty thuc va mi nc. Nh t chc domain ca Vit Nam :
Hnh 1.2 : T chc domain ca Vit Nam.
c) Cu trc tn min :
Tn min c phn thnh nhiu cp nh:
Gc (Domain root): N l nh ca nhnh cy ca tn min. N xc nh kt thc ca
domain. N th din n gin ch l du chm .
Tn min cp mt (Top-level-domain) : L gm vi k t xc nh mt nc, khu
vc hoc t chc. N c th hin l .com
Tn min cp hai (Second-level-domain): N rt a dng rt a dng c th l
tn mt cng ty, mt t chc hay mt c nhn.
Tn min cp nh hn (Subdomain): Chia thm ra ca tn min cp hai tr
xung thng c s dng nh chi nhnh, phng ban ca mt c quan hay ch no . Nh
phone.fpt.vn l mt phng ca cng ty Fpt.
V d: c tn min www.utehy.edu.vn Tn min s c c t tri qua phi.
Mc u tin (www) l tn ca my tnh.
Tip theo l tn min cp 3 (thanglong) , tn min c ng k vi c quan qun
l tn min di cp vn l trung tm thng tin mng Internet Viet
Nam(VNNIC).
Tn min ng th 2 t bn phi l tn min mc 2 (com) tn min ny miu t chc
nng ca t chc s hu tn min mc 3. Trong v d ny t chc ly tn min mc hai
la edu c ngha l t chc thuc v gio dc. Cui cng l tn min .vn, tn min
ny ch ra ton b min ny thuc quyn qun l ca mng Internet Vit Nam.
Mt s ch khi t tn min:
Tn min nn t gii hn t cp 3 n cp 4 v nhiu hn na vic nh tn v qun tr
kh khn.
S dng tn min l phi duy nht trong mng Internet
Nn t tn n gin gi nh v trnh phc tp.
3. My ch qun l tn min (Domain name server-dns)
My ch qun l tn min (dns) theo tng khu vc, theo tng cp nh: mt t
chc, mt cng ty hay mt vng lnh th. My ch cha thng tin d liu v a ch v
tn min trong khu vc , trong cp m n qun l dng chuyn gia tn min v a
ch IP ng thi n cng c kh nng hi cc my ch qun l tn min khc hoc cp cao
hn n c th tr li c cc truy vn v nhng tn min khng thuc quyn qun l ca
n v cng lun sn sng tr li cc my ch khc v cc tn min m n qun l.
My ch cp cao nht l Root Server do t chc ICANN qun l:
L server qun l ton b cu trc ca h thng tn min.
Root Server khng cha d liu thng tin v cu trc h thng DNS m n ch
chuyn quyn (delegate) qun l xung cho cc server cp thp hn v do root
server c kh nng nh ng n ca mt domain ti bt k u trn mng.
Hin nay trn th gii c khong 13 root server qun l ton b h thng
Internet. Di y l cc thng tin v 13 root :
Mt DNS server c th nm bt c v tr no trn mng Internet nhng c cu
hnh logic phn cp chuyn tn min cp thp hn xung cho cc DNS server khc
nm bt c v tr no trn mng Internet. Nhng tt nht l t DNS ti v tr no gn
vi cc client d dng truy vn n ng thi cng gn vi v tr ca DNS server cp
cao hn trc tip qun l n.
Chng II. CU HNH CA NAME SERVER TRONG LINUXI. Ci t BINDHu ht cc
phin bn ca RedHat v Fedora Linux cung cp package BIND.*.Rpm (i vi
FC l bind-9.2.3-13.*.rpm) Mt s package ca BIND trong Fedora:
bind-9.2.3-13i.386.rpm: L package chnh ca DNS Server.
bind-libs-9.2.3-13.386.rpm : Cung cp cc th vin tr gip cho DNS
Server.
bind-utils-9.2.3-13.386.rpm : Cung cp tin ch tch hp cho DNS
Server.
system-config-bind-2.0.2-5.386.rpm : Cung cp giao din cu hnh DNS
Server trn mi trng XWindows. caching-nameserver-7.2-12.386.rpm : L
package cung cp cc file mu h tr cu hnh Caching nameserver v cu hnh
dch v DNS.
caching-nameserver-ltsp-7.2-k12ltsp.5.2.0.386.rpm: l package
cung cp cc file cu hnh mu cho Zone ltsp.
bind-chroot-9.2.3-13.i383.rpm : L package cung cp mt s tnh nng
bo mt mi gii hn truy xut file cu hnh ca dch v DNS.
Ta dng lnh rpm ivh ci t cc package trn.
II. Ci t v cu hnh DNS
1 Mt s file cu hnh quan trng.RedHat/Fedora BIND hot ng trong h
thng di dng tin trnh named do user c tn named lm ch s hu. tng tnh
nng bo mt trong h thng Fedora, BIND cung cp thm package
bind-chroot-9.2.3-13.i386.rpm gii hn vic truy xut vo cc file cu hnh
ca named, khi ta ci chroot package th named xem thu mc
/var/named/chroot l th mc gc, cc file
/var/named/chroot/var/named.conf l tp tin khai bo zone,
/var/named/chroot/var/named l th mc lu tr file c s d liu. Khi ta
dung chroot th tt c cc file cu hnh named u c a vo th mc
/var/nameg/chroot. Nu ta khng s dng package ny ngha l ta loi b
bind-chroot-9.2.3-13.i386.rpm th cc file m t thng tin cu hnh DNS c
lu li. /var/named/chroot/etc/named.conf
/var/named/chroot/var/named
/etc/rndc.key, /etc/rndc.conf l cc file h tr cho vn chng thc
trong named.
1. Tp tin var/named/chroot/etc/named.conf
Tp tin ny cha nhng thng tin quan trng c s dng bi daemon named
khi daemon ny hot ng.Ni dung ca tp tin ny nh sau:// generated by
named-bootconf.ploptions [ ; ch nh cc ty chn.directory
"/var/named"; Th mc lu tr file c s d liu ca zone./** If there is a
firewall between you and nameservers you want* to talk to, you
might need to uncomment the query-source* directive below. Previous
versions of BIND always asked* questions using port 53, but BIND
8.1 uses an unprivileged* port by default.*/// query-source address
* port 53;];// // a caching only nameserver config// controls [inet
127.0.0.1 allow [ localhost; ] keys [ rndckey; ];];zone "." IN
[type hint;file "named.ca";];zone "localhost" IN [type master;file
"localhost.zone";allow-update [ none; ];];zone
"0.0.127.in-addr.arpa" IN [type master;file
"named.local";allow-update [ none; ];];include
"/etc/rndc.key";Optionsnh ngha nhng cu hnh ton cc cho DNS server:C
php:Options [(directory path_name(forwarders [in_addr1; inaddr2;]
(allow_query [address_match_list](notify yes/no(also-notify
[ip_addr1, ip_addr2.;](allow-update [ip-addr1; ip-addr2;]Directory
Forwarders: danh sch a ch IP ca cc name server m n s gi yu cu truy
vn khi cn.Allow-query: danh sch a ch IP c php truy vn CSDL
DNS.Notify: mc nh c set l yes, khi c s thay i trn CSDL th name
server s gi thng bo v s thay i ny cho cc name server trong danh sch
name server c lit k trong record NS v cc name server c khai bo
trong ty chn also-notify.Also-notify: a ch IP ca cc name server s c
gi thng bo khi c s thay i trn CSDL DNS.Allow-update: quy nh vic cc
my trong min c c php cp nht DNS ng hay khng, mc nh vic ny b cm i vi
tt c cc my.Zonenh ngha mt zone qun l CSDL cho min hay min con.C
php:Zone (domain-name) IN [Type master/slave/hint/stub;File
path_name;];Type: Master: server c bn copy chnh CSDL Slave: server
lu mt bn sao CSDL t master. Nu mt tp tin c ch ra n s sao chp ton b
zone master v. Stub: tng t nh slave nhng ch sao chp record NS t
Master ch khng phi ton b d liu. Hint: zone ch ra nhng root name
server.Masters: a ch IP ca master name server.File: tp tin nh ngha
CSDL2. Cu hnh zone file
To tp tin c s d liu phn gii tn my thnh a ch IP (tp tin phn gii
thun ).
To tp tin c s d liu phn gii a ch IP thnh tn my (tp tin phn gii
ngc ).
Sau y l tun t cc bc:
Bc 1: To tp tin c s d liu phn gii tn my thnh a ch IP .
To tp tin c s d liu phn gii tn thnh a ch IP. Tp tin ny lu danh
sch tt c nhng my tnh trong min. N c dung phn gii tn my (host name)
thnh a ch IP.
$ TTL 86400
@ IN SOA localhost. root.localhost. (
2001112800;
10800;
1800;
36000;
86400)
IN NS localhost.
Bc 2: To tp tin c s d liu phn gii a ch IP thnh tn my (tp tin phn
gii ngc ).
$ TTL 86400
@ IN SOA localhost.. root.localhost. (
2001112800;
10800;
1800;
36000;
86400)
IN NS localhost.
1 IN PTR localhost.
Bc 3: Cu hnh DNS Client.Cu hnh DNS Client nhm s dng cng c
nslookup kim tra nhng name Server va cu hnh. Trong Linux, nhng thng
s cu hnh DNS client c lu trong tp tin /etc/resolv.conf . Tp tin dng
quyt nh DNS Server c th cn phi truy vn v cch b sung phn tn min cho
phn tn ca my. Ni dung ca tp tin c dng sau:i vi may Linux ta vao tp
tin /etc/resolv.conf thm vao 2 dong sau :
nameserver < name server IP>
domain
Trong :
nameserver : dng nh ngha my ch DNS m resolver s gi yu cu phn gii
tn hoc a ch IP khi c nhu cu. Sau t kha nameserver l a ch IP ca Name
Server.
domain : s c ni thm vo sau tn my tnh khi resolver gi yu cu n
server.
Bc 4: Khi ng v kim tra hot ng ca dch v DNS
Khi hon thnh cc thao tc cn thit cu hnh cho my ch DNS, ta khi ng
dch v bng lnh: service named restart. Ri ta tip tc kim tra khng nh
nhng cu hnh ny ng hay cn sai st nhng im no. Mt cng c c lc gip kim
tra cu hnh DNS l nslookup hoc lnh host.# service named restart
# nslookup
>www.localhost
Server: localhost
Address: localhost IP
Kim tra cc Record ca min bng lnh:
>Set type=any
>domain_name
2. V d cu hnh DNSBc 1: To tp tin
/var/name/chroot/etc/name.conf
cu hnh mt file cho min detai.com nh sau:
zone detai.com IN {
type master;
file detai.com;
;}zone 5.168.192.in-addr.arpa. IN {
type master;
file 192.168.5.db;
;}
Bc 2: To tp tin phn gii thun
Tn ca tp tin l: detai.com
$ TTL 86400
@ IN SOA ns.detai.com. root.detai.com. (
2001112800;
10800;
1800;
36000;
86400)
IN NS ns.detai.com. IN MX 10 mail.detai.com.
ns IN A 192.168.5.19
www IN CNAME ns.detai.com.
mail IN A 192.168.5.19
Bc 3: To tp tin phn gii nghch
Tn ca tp tin l: 192.168.5.db
$ TTL 86400
@ IN SOA ns.detai.com. root.detai.com. (
2001112800;
10800;
1800;
36000;
86400)
IN NS ns.detai.com.
IN MX 10 mail.detai.com.
19 IN PTR ns.detai.com.
Bc 4: Cu hnh Client
Ni dung ca tp tin /etc/resolver
Namerserver 192.168.5.19
Domain detai.com
Bc 5: Khi ng v kim tra hot ng ca dch v DNS# Service named
restart
# nslookup
IV. Cu hnh Secondary Name Server
Tng t nh cu hnh Primary Name Server nhng c mt s im khc: Khng to
cc file CSDL cho zone. Cc file ny s c sao chp t Primary Name
Server. Trong tp tin /var/named/chroot/etc/named.conf thay th thuc
tnh type l master thnh slave Cung cp a ch IP ca Primary Name
Server.
V d : Di y l file /var/named/chroot/etc/named.conf cu hnh
Secondary Name Server cho domain detai.comzone detai.com IN {
type slave;
file slaves/detai.com;
masters {192.168.5.19 ; port 53; }
;}zone 5.168.192.in-addr.arpa. IN {
type slave;
file slaves/192.168.5.db;
masters {192.168.5.db ; port 53; }
;}
V. Cu hnh DNS delegation
Hnh 1.10
Thng thng min cha cung cp cc domain con cho min con di hnh thc y
quyn cho min con t qun l v t chc c s d liu cho min con (thut ng ny
thng c gi l delegation domain), hoc min cha to hosting domain cho
min con (theo cch ny th min cha phi t chc v qun l c s d liu cho min
con). Da vo s trn ta thc hin cc thao tc c sau thc hin cng vic cung
cp subdomain qua c ch y quyn cho cc nameserver qun l c s d liu ca
min con. Ti nameserver qun l c s d liu ca min con. Ti nameserver
qun l c s d liu cho min com.vn ta c thng tin sau thc hin c ch y
quyn cho hai min con l vinamilk.com.vn v honda.com.vn v cho 1
server vinamilkserv v hondaserv qun l:
VinamilkservINA
Vinamilk
INAvinamilkserv.com.vn
Trong IPaddress 1 l a ch ca nameserver qun l c s d liu cho min
vinamilk.com.vn. Sau ta cn m t RR PTR cho vinamilkserv trong file m
t c s d liu ch zone ngch.
INPTRvinamilkserv.com.vn
Tng t ta c th y quyn min Honda.com.vn cho hondaserv
Hondaserv
INA
Honda
INNShondaserv.com.vn
Trong ipaddress 2 l a ch Ip ca nameserver qun l c s d liu cho
min Honda.com.vn
Sau ta cn m t RR PTR cho hondaserv trong file m t c s d liu cho
zone ngch.
IN PTR
hondaserv.com.vn
Lu : min con ta cn m t forwarders (ipaddress; ) ln min cho min
con nh nameserver ca min cho phn gii tn min bn ngoi cho min
con.
Kt lun
Dch v DNS ra i gip cho vic truy cp ti cc web site t bt c u c dng
hn. Thay v nh a ch IP, dch v DNS phn gii a ch IP thnh tn my, gip
cho vic tm hiu, trao i thng tin mt cch n gin linh hot.
Qua qu trnh tm hiu di s hng dn ca thy V Xun Thng v tham kho kin
ng gp ca cc thy gio b mn v cc bn tp th TK10.2, Chng em hon thnh bi
tp ln DNS trn LINUX trnh by r cc vn n sau:
Gii thiu v DNS.
Cu hnh DNS.
Trong qu trnh thc hin cng c mt s vn xy ra nhng c khc phc.
u im ca dch v:
Gip ngi dng d dng nh v truy cp ti nguyn mng.
An ton v tin cy.
Vic qun tr tp trung v d dng hn.
Mc tiu ca bi tp ln: Gii thiu c ch t chc v qun l dch v DNS trn mi
trng LINUX.
Ti Liu tham kho
Google.com.vnTailieu.vn
Quantrinmang.com
Hnh 1.3: V tr ca 13 Root name trn bn th gii.
PAGE 21L c Hip L nh Phong TK 10.2
