6 8 p olicies firewa ll. Di DMZ da p a t dile ta kka n la ya na n-la ya na n we b
da n FTP ya ng m e m p e rb o le h k a n p e n g g u n a lu a r u n tu k m e nga ks e s s e rvis te rs e but.
De nga n c a ra ini a ks e s da ri lua r ha nya a ka n dia ra hka n p a da s a tu s e gm e n DMZ s a ja da n ja ringa n da la m tida k bole h dia ks e s da ri
lua r.
4.3 IPTables
Da la m ip ta bles a da tiga la bel uta m a , ya itu: INPUT : p a c ke t da ta ya ng m a suk da ri inte rfa c e kita
OUTPUT : p a c ke t da ta ya ng ke lua r da ri inte rfa c e kita F O RWARD : p a c ke t da ta ya ng m e n u m p a n g u n tu k lewa t
PAKET MASUK KEPUTUSAN
ROUTING FORWARD
PAKET KELUAR
INPUT PROSES LOKAL
OUTPUT
Gam bar 4 .3 A lg oritm a k ep u tu s an rou tin g
4.3.1 Operasi pada Iptables
Be rikut ini a da la h op e ra si da la m Ip ta ble s:
Tabel op eras i p ad a Ip tables
Ope ras i Ops i
Me m bua t c ha in ba ru -N
6 9 Me n g h a p u s c h a in k o s o n g
-X Me ruba h a tura n da ri s ua tu c ha in
-P Me liha t da fta r rule s
-L Me n g h a p u s s e lu ru h ru le s
-F Me nolka n hitunga n p a ke t da n byte da la m s ua tu c ha in
-Z Me na m ba hka n rule ba ru p a da s ua tu c ha in
-A Me m a s ukka n rule ba ru p a da p os is i te rte ntu da la m
s ua tu c ha in -I
Me ngga nti rule p a da s ua tu c ha in p a da p os is i te rte ntu -R
Me ngha p us rule p a da c ha in te rte ntu da n p a da p os is i te rte ntu a ta u ya ng s e s ua i de nga n s p e s ifika s i
-D
4.3.2 Parameter Iptables
Pa ra m e te r diguna ka n untuk m e m bua t a tura n le bih s p e s ifik bia s a nya diguna ka n p a da p e na m ba ha n, p e ngha p us a n, p e nyis ip a n,
a ta u op e ra s i p e ngga ntia n.
Tabel p aram eter p ad a Ip tables
Parame te r Ops i
Me n u n ju k k a n n a m a p ro to k o l ya n g d ig u n a k a n , b is a tcp , u d p , icm p , a ta u all
-p Me n u n ju k k a n sou rce ad d res
-s Me n u n ju k k a n d estin asi ad d ress
-d -j
Me nunjukka n inp ut da ri inte rfa c e -i
Me n u n ju k k a n o u tp u t d a ri in te rfa c e -o
7 0
4.3.3 Contoh Penggunaan Iptables
Server B1:192.168.1.5 host A1: 192.168.2.5
host B2 :192.168.1.15
eth0 : 192.168.2.2
eth1 : 192.168.1.2
Gam bar 4 .4 S k en ario p enerap an ip tabels p ad a 2 netw ork Table Filter chain Forw ard
Nam a S ubne t 1 9 2 .1 6 8 .1 .0
1 9 2 .1 6 8 .2 .0 1 9 2 .1 6 8 .1 .0
ACCEPT 1 9 2 .1 6 8 .2 .0
ACCEPT Pe rinta h Ip ta ble s a da la h s e ba ga i be rikut :
iptables - -P INPUT DROP
iptables - -P OUTPUT DROP
iptables - -P FORWARD DROP
Pe rinta h di a ta s dibua t a ga r s e luruh ke bija ka n p e rta m a p olic y u n tu k p e rta m a ka li a da la h DRO P.
Pe rin ta h u n tu k m e le wa tk a n p a k e t d a ri n e two rk A k e n e two rk B m e la lui route r a da la h s e ba ga i be rikut :
echo 1procsysnetipv4ip_forward iptables -
-A FORWARD - -i eth0 -
-o eth1 - -j ACCEPT
iptables - -A FORWARD -
-i eth1 - -o eth0 -
-j ACCEPT
Arti p e rinta h di a ta s be rturut-turut a da la h s e ba ga i be rikut: Me m a s tika n ba ris forwa rding dia ktifka n
7 1 Me m bua t a ga r ne twork A da p a t m e nya p a B
Me m bua t a ga r ne twork B da p a t m e nya p a ne twork A Piliha n:
J ika diinginka n A la ngs ung dija wa b ole h B ha nya u n tu k setia p ka li A m e la kuka n p a nggila n m a ka p e rinta hnya a da la h s e ba ga i
b e rik u t:
iptables - -A FORWARD -
-i eth0 - -o eth1 -
-j ACCEPT iptables -
-A FORWARD - -i eth1 -
-o - -m state -
--state ESTABLISHED -
- j ACCEPT
J ika diinginka n a ga r ha nya host te rte ntu sa ja , ya itu B2 , ya ng da p a t m e nja wa b p a nggila n A1 m a ka g u n a k a n p e rin ta h b e rik u t:
iptables - -A FORWARD -
-i eth0 - -o eth1 -
-j ACCEPT iptables -
-A FORWARD - -i eth1 -
-o eth0 - -s 192.168.1.6 -
-d 192.168.2.5 -
-m state - --state ESTABLISHED -
-j ACCEPT
Pe rinta h a ga r fire wa ll da p a t di-re m ote da ri B1 a da la h:
iptables - -A INPUT -
-p tcp - -s 192.168.1.5 --
-dport 22 - - j
ACCEPT iptables -
-A OUTPUT - -o eth1 -
-m state - --state
ESTABLISHED - -j ACCEPT
4.3.4 Kegunaan IPTables
