View source for Script NAT Proxy untuk Modem 3G

Pastikan terlebih dulu sambungan 3G telah terjalin dengan baik. Salah satu yang paling mudah adalah [[Penggunaan Vodafone Mobile Connect Card Driver For Linux]].

Selanjutnya baru kita dapat menjalankan script Internet Connection Sharing ini. Isi detail script silahkan lihat di bawah.
Untuk menjalankan script

 # ./script.sh start

Untuk mematikan

 # ./script.sh stop

Agar script.sh langsung on waktu komputer di booting, anda dapat menuliskan script tersebut di folder (misalnya) /root. Masukan pada file /etc/rc/local perintah

 /root/script.sh start


Isi script.sh adalah seperti tampak di bawah ini. Ada beberapa parameter yang perlu di perhatikan yaitu

* UPLINK
* NAT
* INTERFACES 

Pastikan bahwa anda mengisi ketiga-nya dengan benar.




==Script Internet Connection Sharing==




 #!/bin/bash
 # From: AHK <akuhon@kompas.com>
 # To: linux-admin@linux.or.id
 # Save this file and activate through # file_name start
 # and de-activate through # file_name stop

 # This firewall-script can be used for workstation, laptop, router
 # or server that are not running network service (such as web server, ftp
 # server etc)

 # change the parameter UPLINK with Interface device to the Internet.
 # In our case WLAN router with NIC wlan0 connected to the Internet
 # and LAN connection with eth0.
 # if you use dial-up modem, you might use ppp0 as your UPLINK

 UPLINK="ppp0"

 # if you run the gateway as router and forward IP packet between eth devices
 # please fill .yes., if not, please fill .no.

 ROUTER="yes"
 
 # Please change 192.168.1.100 to your static IP address of UPLINK device.
 # For those who use dial-up or dynamic IP, please enter .dynamic.

 # NAT="192.168.1.100"

 NAT="dynamic"

 # please list all network interfaces including eth devices
 # as well as dial-up interface such as ppp0

 INTERFACES="lo eth0 eth1 eth2 ppp0"

 if [ "$1" = "start" ]
   then
   echo "Activate Firewall ..... "
   /sbin/iptables -F
   /sbin/iptables -P INPUT DROP
   /sbin/iptables -A INPUT -i ! ${UPLINK} -j ACCEPT
   /sbin/iptables -A INPUT -i ${UPLINK} -p tcp -s 0/0 --dport 25 -j ACCEPT
   /sbin/iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
   /sbin/iptables -A INPUT -p tcp -i ${UPLINK} -j REJECT --reject-with tcp-reset
   /sbin/iptables -A INPUT -p udp -i ${UPLINK} -j REJECT --reject-with icmp-port-unreachable

 # turn off packet spoofing in all interfaces
 for x in ${INTERFACES}
   do
     echo 1 > /proc/sys/net/ipv4/conf/${x}/rp_filter
   done 

 if [ "$ROUTER" = "yes" ]
   then
   # Activate IP forwarding at router
     echo 1 > /proc/sys/net/ipv4/ip_forward
 if [ "$NAT" = "dynamic" ]
   then
   # Dynamic IP address, activate Masquerading
     echo "Activate Masquerading (Dynamic IP) ...."
     /sbin/iptables -t nat -A POSTROUTING -o ${UPLINK} -j MASQUERADE
 elif [ "$NAT" != "" ]
   then
   # Static IP address use source NAT
   echo "Activate SNAT (static IP) ...."
   /sbin/iptables -t nat -A POSTROUTING -o ${UPLINK} -j SNAT --to ${NAT}
 fi

 fi
   elif [ "$1" = "stop" ]
     then
       echo "Deactivate Firewall ..."
       /sbin/iptables -F INPUT
       /sbin/iptables -P INPUT ACCEPT
       /sbin/iptables -F FORWARD
       /sbin/iptables -P FORWARD ACCEPT
       /sbin/iptables -F OUTPUT
       /sbin/iptables -P OUTPUT ACCEPT
       # Turn off NAT or MASQUERADING
       /sbin/iptables -t nat -F POSTROUTING
 fi



==Pranala Menarik==

* [[Wireless Internet]]