giffgaffer's guide to connect a 3G Modem On DD-WRT
on: 11/03/2012 | 20:34 - edited: 28/05/2016 | 16:13
giffgaffer's guide to connect a 3G Modem On DD-WRT
This is a guide to setting up your DD-WRT modem for giffgaff. The instructions mentioned are based upon NETGEAR WDR3400 V1. There will also be slight different variations according to DD-WRT firmware.
First, See if your Router is compatible, You can do this in lots of ways.
1) Router Database https://www.dd-wrt.com/site/support/router-database
2) DD-WRT Forums (Search your Model Number) http://www.dd-wrt.com/phpBB2/search.php
Then upgrade to the latest DD-WRT builds (Sorry FTP is only available) ftp://ftp.dd-wrt.com/betas/2016
Once you have flash to DD-WRT, Follow the steps below;
Log in http://192.168.1.1 with the username and password in the pop-up window:
WAN Setup -
Connection Type: 3G/UMTS/4G/LTE
Username: giffgaff
Password: password
Dial String: *99#
APN: giffgaff.com
Connection type: 3G first on error 2G
Force reconnect: you decide!
Network Setup -
Start IP Address: 10
Maximum DHCP Users: 9
Hit Save
Go to Wireless tab at the top, You will see something like...
Physical Interface wl0 - SSID [dd-wrt] HWAddr [C4:3D:XX:XX:XX:XX]
Wireless Mode: AP
Wireless Network Name (SSID): ANY WIRELESS NAME YOU WONT E.G giffgaff 3G
Wireless Channel: Auto
Channel Width: Auto
Hit Save
Go to Wireless Security at the top
Security Mode: WPA2 Personal
WPA Algorithms: AES+TKIP
WPA Shared Key: YOUR WIRELESS PASSWORD
Hit Save, Go to Services at the top
Static Leases (Skip if you dont wont to reserve IP addresses)
Import you PC, Laptop or any mac address you would like to reserve (good for \\ SAMBA, Printer sharing etc
Hit Save, Apply settings
Reboot
Once rebooted unplug the DD-WRT device and put in your 3G dongle
You should see WAN IP: 10.x.x.x
Latestly, Go to Administration then Commands and import this info the white box
#!/bin/sh
PROXY_IP=193.113.200.195
PROXY_PORT=8080
LAN_IP=`nvram get lan_ipaddr`
LAN_NET=$LAN_IP/`nvram get lan_netmask`
iptables -t nat -A PREROUTING -i br0 -s $LAN_NET -d $LAN_NET -p tcp --dport 80 -j ACCEPT
iptables -t nat -A PREROUTING -i br0 -s ! $PROXY_IP -p tcp --dport 80 -j DNAT --to $PROXY_IP:$PROXY_PORT
iptables -t nat -I POSTROUTING -o br0 -s $LAN_NET -d $PROXY_IP -p tcp -j SNAT --to $LAN_IP
iptables -I FORWARD -i br0 -o br0 -s $LAN_NET -d $PROXY_IP -p tcp --dport $PROXY_PORT -j ACCEPT
Hit Save Firewall
and reboot and power off and on again.
Enjoy 
on: 21/10/2015 | 16:56