Cara Membuat PC Router Menggunakan Linux Fedora

Dalam Hal ini dipakai Fedora Core XX menggunakan 2 ethernet card :
- eth0  : ethernet card dengan ip public (static atau dhcp tergantung provider)
- eth1  : ethernet card Lokal (sebagai gateway utk klien2)

Langkah awal install-lah Fedora XXX sesuaikan dengan keperluan.
login menggunakan root , lalu :

konfigurasi ip address eth0 , misal xxx.xxx.xxx.xxx (ip public static atau dhcp tergantung provider )
# vi /etc/sysconfig/network-scripts/ifcfg-eth0

konfigurasi ip address eth1 , misal 192.168.10.1 dengan netmask 255.255.255.0 (192.168.10.1/24)
# vi /etc/sysconfig/network-scripts/ifcfg-eth1

konfigurasi ip address diatas dapat juga dilakukan saat menginstall fedora.
(untuk konfigurasi sesuaikan editor dengan kebiasaan anda, disini di contohkan menggunakan vi)

#  vi /etc/sysctl.conf
ubahlah
# Controls IP packet forwarding
net.ipv4.ip_forward = 1 <<<<<< ubah dari 0 menjadi 1.

kemudian kita edit iptables
# vi /etc/sysconfig/iptables
tambahkan NAT
*nat
-A POSTROUTING -s 192.168.10.0/24 -o eth0 -j MASQUERADE (utk ip address 1 s/d 254)

bila kita menginnginkan tidak semua ip yg dapat terkoneksi ke internet gunakan :
-A POSTROUTING -s 192.168.10.10 -j SNAT –to-source xxx.xxx.xxx.xxx

Contoh lengkap :
*nat
 REROUTING ACCEPT [127173:7033011]
 OSTROUTING ACCEPT [31583:2332178]
:OUTPUT ACCEPT [32021:2375633]
-A POSTROUTING -s 192.168.10.0/24 -o eth0 -j MASQUERADE
atau
-A POSTROUTING -s 192.168.10.10 -j SNAT –to-source xxx.xxx.xxx.xxx
(pilih salah satu)
COMMIT

*mangle
 REROUTING ACCEPT [444:43563]
:INPUT ACCEPT [444:43563] :FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [402:144198]
 OSTROUTING ACCEPT [402:144198]
-A PREROUTING -p tcp -m tcp –tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,PSH,URG -j DROP
-A PREROUTING -p tcp -m tcp –tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP
-A PREROUTING -p tcp -m tcp –tcp-flags SYN,RST SYN,RST -j DROP
-A PREROUTING -p tcp -m tcp –tcp-flags FIN,SYN FIN,SYN -j DROP
-A PREROUTING -m tos –tos Minimize-Delay
-A PREROUTING -p tcp –sport ssh -j TOS –set-tos Minimize-Delay
-A OUTPUT -p tcp –dport ssh -j TOS –set-tos Minimize-Delay
COMMIT

*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:icmp_packets – [0:0]

-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp –dport 22 -j ACCEPT
-A INPUT -p icmp -j icmp_packets
-A INPUT -m state –state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -j REJECT –reject-with icmp-host-prohibited

-A FORWARD -p icmp -j icmp_packets
-A FORWARD -s 10.10.10.0/24 -j ACCEPT
-A FORWARD -m state –state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -j REJECT –reject-with icmp-host-prohibited

-A OUTPUT -p tcp –dport 135 -j DROP
-A OUTPUT -p udp –dport 137 -j DROP
-A OUTPUT -p udp –dport 138 -j DROP
-A OUTPUT -p tcp –dport 139 -j DROP
-A OUTPUT -p tcp –dport 445 -j DROP
-A OUTPUT -p icmp -j icmp_packets
-A OUTPUT -m state –state RELATED,ESTABLISHED -j ACCEPT

-A icmp_packets -p icmp -m icmp –icmp-type 0 -j ACCEPT
-A icmp_packets -s 127.0.0.1 -p icmp -m icmp –icmp-type 8 -j ACCEPT
-A icmp_packets -s xxx.xxx.xxx.xxx/xx -p icmp -m icmp –icmp-type 8 -j ACCEPT
-A icmp_packets -s 192.168.10.0/24 -p icmp -m icmp –icmp-type 8 -j ACCEPT
-A icmp_packets -p icmp -m icmp –icmp-type 8 -j DROP
-A icmp_packets -p icmp -m icmp –icmp-type 3 -j ACCEPT
-A icmp_packets -p icmp -m icmp –icmp-type 11 -j ACCEPT
COMMIT

Setelah selesai simpan dengan menggunakan esc : wq

Reboot PC Router dan cobalah mengkonfigurasi ip address diklien dengan address :
ip address 192.168.10.10
netmask 255.255.255.0
gateway 192.168.10.1
DNS sesuaikan dengan dns providermu
Silahkan akses internet menggunakan PC klien tadi, selamat anda telah berhasil membuat
Router NAT menggunakan Linux (Fedora)

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