Turn any computer into a 3G router in fixnum minutes

2012-06-17 Updated 2026-06-17

Quick and dirty howto. I'll use a Huawei E174 3G USB modem with a working sim hard, and a Zyxel G-220 USB wi-fi adapter. First, install ppp and configure the the 3G modem by writing a chat script and setting ppp options in /etc/ppp/peers/provider:

connect "/usr/sbin/chat -v \
TIMEOUT 35 \
ECHO    ON \
ABORT   '\nBUSY\r' \
ABORT   '\nERROR\r' \
ABORT   '\nNO ANSWER\r' \
ABORT   '\nNO CARRIER\r' \
ABORT   '\nNO DIALTONE\r' \
ABORT   '\nRINGING\r\n\r\nRINGING\r' \
ABORT   '\nUsername/Password Incorrect\r'  \
''      \rAT \
OK      'AT+CGDCONT=1,\"IP\",\"web.be\"' \
OK      'ATD*99#' \
CONNECT '\d\c'"
/dev/ttyUSB0
115200
crtscts
noauth
usepeerdns
#noipdefault
persist
debug
defaultroute
user "web"
password web

Then, install hostapd and configure the wi-fi card in master mode in /etc/hostapd.conf:

interface=wlan1
bridge=br0
driver=nl80211
ssid=MyNetwork
hw_mode=g
channel=1

start the card in master mode, assign an IP address to it hostapd /etc/hostapd.conf ifconfig wlan1 192.168.0.1 Then install and configure the DHCP server in /etc/dhcp/dhcpd.conf by adding the following lease configuration:

subnet 192.168.0.0 netmask 255.255.255.224 {
  range 192.168.0.10 192.168.0.20;
  option routers 192.168.0.1;
  option domain-name-servers 8.8.4.4;
}

start the ppp daemon using pon provider this also sets dns and the default gateway properly.