Bridged Billion BiPAC 7402L ADSL Router and Smoothwall
This page provides information on configuring a Billion BiPAC 7402L ADSL Router
in bridge mode with Smoothwall.
Billion BiPAC 7402L
The Billion BiPAC 7402L
ADSL router provides ADSL2/2+ support (upto 24Mbps), and has
four 10/100Mbps ethernet ports for connectivity, as well as having a
DHCP server, PPPoA and PPPoE clients, and a web interface for configuration and adminstration.
It also provides firewall support, dynamic DNS, QoS, and several other features, but
I prefer to handle these services on linux boxes behind the router,
and have the 7402L configured in pure bridge mode.
Billion BiPAC 7402L ADSL Router
Configuring With Smoothwall
The default configuration of the 7402L will result in it NAT-ing all traffic.
However, I prefer to allow my Smoothwall box to handle the NAT (and
double NAT is nasty).
I tried configuring the 7402L in half-bridge mode (referred to as "PPPoE with pass-through" in
the admin interface), but couldn't get it to work properly.
As a result, I had to revert to a pure bridged configuration, with Smoothwall
handling PPPoE.
Note that the 7402L's default IP address is
192.168.1.254 with a netmask 255.255.255.0.
As a result, you need to ensure your green and orange networks do not use addresses
that overlap this IP address, as that will prevent you from being able to access
the modem's web interface through your Smoothwall.
Alternatively, the 7402L's LAN IP address can easily be changed through its web interface
(under Configuration -> LAN -> Ethernet).
Configure Smoothwall's red interface for PPPoE, by running setup from a
command prompt on Smoothwall, then navigating to
Networking -> Address settings -> RED, and select PPPoE.
Smoothwall red interface configuration
Connect one of the 7402L's ethernet
ports to your Smoothwall's red interface using a straight-through ethernet cable
(a cross-over cable will also work).
Using Smoothwall's web interface, on the Networking -> PPP Settings page,
configure the PPP interface for PPPoE, turn on the "Persistent Connection" checkbox,
and specify your username and password.
configure the interface for PPPoE
enter username, password, and authentication method
If necessary, specify the authentication method and a custom login script.
Mine worked fine using the default "PAP or CHAP" authentication.
With Smoothwall's red interface configured for PPPoE, you will no longer be able to
access the 7402L's web interface through Smoothwall,
as the 7402L's default IP address is 192.168.1.254, and Smoothwall's red interface
defaults to an IP address of 1.1.1.1 when using PPPoE.
To correct this, edit /etc/rc.d/rc.netaddress.up, and
change the IP address in the line containing
ifconfig $RED_DEV 1.1.1.1 netmask 255.255.255.0 broadcast 1.1.1.255 up
to an IP address which is in the same subnet as the 7402L's IP address, such as:
ifconfig $RED_DEV 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255 up
To make this change take effect, you'll need to restart Smoothwall's red interface:
/etc/rc.d/rc.netaddress.down; /etc/rc.d/rc.netaddress.up
You should now be able to ping the 7402L's IP address (192.168.1.254,
if you haven't changed its IP address) from your Smoothwall, and from any PC on the green network.
The default login account for the 7204L is admin/admin.
Using a browser on a PC your green network, go to the modem's web interface
at http://192.168.1.254.
Navigate to the Quick Start page, and set the "Encapsulation" to "Pure Bridged LLC", and
disable NAT. Hit the "Apply" button to apply the changes.
router configuration
Now navigate to the Configuration -> WAN -> ADSL page, and set the "Connect Mode"
appropriately for your ISP, and hit the "Apply" button.
ADSL configuration
Navigate to the Configuration -> Firewall -> General Settings page, and ensure that
the firewall is disabled, and hit the "Apply" button.
Click the "Save Config" link at the bottom of the page, then the "Apply" button
to save your changes to flash memory in the 7402L.
Once the save operation is complete, reboot the 7402L.
Confirm that the 7402L connects successfully by checking the "Port Status" on the
"Status" page in the web interface. When successfully synced, it should show a green
tick underneath the "ADSL" link.
green tick shows an active ADSL
Click the "ADSL" link to see more details of the connection, including sync speeds.
Navigate to the main page of Smoothwall's web interface, and it should show
the current profile as being idle.
Hit the "Connect" button to initiate a PPPoE connection to your ISP,
and Smoothwall's web interface should show a connection being established ("dialing..."),
and shortly afterwards, should show an active connection, as well as the duration of
that connection.
Smoothwall's front page showing an active PPPoE connection
(connection has been active for just over 1 day and 4 hours)
If Smoothwall fails to establish a PPPoE connection, check Smoothwall's syslog
(/var/log/messages) for more details.
Note that you can connect additional devices to the other ethernet ports on the 7402L,
and should be able to get an IP address from the 7402L's DHCP server.
However, each device will need to run it's own PPPoE session (if your ISP supports multiple
PPPoE connections) to obtain internet access
(connecting a PC to Smoothwall's green network will provide internet access without
requiring the PC to run a PPPoE session).
Syncronising the 7402L's Clock
The 7402L normally will synchronise its clock to upto four NTP servers on the internet.
With the 7402L in full bridged mode, it cannot access the internet itself.
As a result, the 7402L cannot sync its clock, so the clock will revert to
1 January 1970 each time it is rebooted.
You cannot manually set the 7402L's clock via the web interface, or by telnetting to it.
If you want the clock to be correct (so the 7402L's event log and diagnostics will be timestamped
correctly), you'll need to configure the 7402L to synchronise to an NTP server on your own network.
I have an NTP server running on my green network, but it's not just a simple matter of port-forwarding
UDP port 123 from Smoothwall's red interface to the NTP server on the green network.
This is because Smoothwall's port-forwarding only forwards traffic it sees on its red interface,
which is the PPPoE interface (ie, the ppp0 interface).
However, the NTP request from the 7402L will be coming in on
Smoothwall's physical interface, which in my case, is eth2
(it will be eth1 if your Smoothwall box doesn't have an orange interface).
Firstly, to configure the 7402L to use a green NTP server, go to the 7402L's web interface,
and navigate to the Configuration -> System -> Timezone page, and specify
the red IP address of your Smoothwall as the only NTP server.
NTP server configuration
Click the "Save Config" link at the bottom of the page,
then the "Apply" button to save your changes to flash memory in the 7402L.
On Smoothwall, manually configure the port-forward by editing
/etc/rc.d/rc.firewall.up,
and add this to the end of the file:
# define IP address of NTP server on green network
ntpserver="172.16.0.2"
# port-forward NTP requests from ADSL modem to green NTP server
/sbin/iptables -N ntp
/sbin/iptables -A ntp -p UDP --dport 123 -d -j ACCEPT
/sbin/iptables -I FORWARD -j ntp
/sbin/iptables -t nat -N ntp
/sbin/iptables -t nat -A ntp -i $RED_DEV -p UDP --dport 123 -j DNAT --to $ntpserver:123
/sbin/iptables -t nat -A PREROUTING -j ntp
Restart Smoothwall's firewall to make this change take effect:
/etc/rc.d/rc.network.down; /etc/rc.d/rc.network.up
Note that you many need to edit the configuration of your NTP server
to allow the modem to access it.
On my linux NTP server, this involved editing /etc/ntp.conf
and adding the following line to explicitly allow the 7402L to connect:
restrict 192.168.1.254 mask 255.255.255.255 nomodify
The NTP server had to be restarted to make this change take effect:
/etc/init.d/ntpd restart
The 7402L should now be able to synchronise its clock to your NTP server,
and will do so whenever it reboots, as well as periodically.
If you can't get it working, I'd suggest using tcpdump
on Smoothwall's red and green interfaces, to confirm the NTP traffic
is being handled correctly, and also on your NTP server.
last updated 6 Mar 2007
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