Membuat PC Router sebagai Default Gateway dengan Debian 4

Bahan
1, Lancard minimal 2
2. PC dengan OS Debian 4
3. Acces point
4. Kabel UTP

Langkah-langkah
1. Meberikan IP untuk 2 lancard
#vim /etc/network/interfaces
Eth0
Address 192.168.2.2
Network 192.168.2.0
Broadcast 192.168.2.255
Netmask 255.255.255.0


Eth1
Address 118.98.171.230
Netmask 255.255.255.248
Network 118.98.171.224
Broadcast 118.98.171.231
Gateway 118.98.171.225

Esc : wq
#/etc/init.d/network restart

2. Cek Kofigurasi IP
#ifconfig eth0
#ifconfig eth1

3. Mengaktifkan fungsi routing
#echo “1” > /proc/sys/net/ipv4/ip forward
Atau
#vim /proc/sys/net/ipv4/ip forward
1
Esc :wq

4. MEngecek fungsi routing
#cat /proc/sys/net/ipv4/ip forward
#vim /proc/sys/net/ipv4/ip forward
Hasilnya harus 1

5. Membuat NAT (network address translation)
#iptables –A POSTROUTING –j MASQUERADE – t nat –s 192.168.2.0/24 –o eth0 (mebuat natnya)
# iptables –A FORWARD –i eth1 -s 192.168.2.0/24 – j ACCEPT (Mengijinkan semua cliet sambung internet)
#iptables –A FORWARD –i eth1 –s 192.168.2.1/24 –j ACCEPT
#iptables –A FORWARD –i ppp0 –s 192.168.2.0/24 –j ACCEPT (menggunakan modem serial)
#iptables –A FORWARD –i eth1 –s 192.168.2.1/24 –j DROP
(menolak ip 192.168.2.1 untuk sambung internet)

6, Konfigurasi Client
Windows
Isi IP lengkap dengan gateway nya

Linux
#ifconfig eth0 192.168.2.1 netmask 255.255.255.0 network 192.168.2.0 broadcast 192.168.2.255 up
#route add –net default gw 192.168.2.2
(Akan hilang jika computer di restart)
Atau
#vim /etc/network/interfaces
Address 192.168.2.1
Network 192.168.2.0
Broadcast 192.168.2.255
Netmask 255.255.255.0
Gateway 192.168.2.2
Esc : wq

#/etc/init.d/network restart

7. Mengisi dns pada client
Linux
#vim /etc/resolv.conf
Nameserver 118.98.224.2
Nameserver 202.134.10.1
Esc : wq

8. Menguji dari client
#ping 192.168.2.2 (gateway)
#ping 118.98.171.230 (eth1 router) ----> fungsi ip forward
#ping 118.98.171.225 (ISP) -------->fungsi nat
#ping google.co.id (web site)---------> fungsi dns