Wednesday, January 07, 2009

Access Modem Configuration From Behind Router

I have a Linksys WRT54GSv4 Router running DD-WRT connected to a Paradyne 6211-I1 (now Zhone) ADSL modem. My connection is pure DHCP. The router gets a public IP just by turning it on.

I wanted to access the modem config pages to view the sync rates without having to plug my computer directly in to the modem. This way I had real numbers to base my QOS settings on.

The dd-wrt wiki Talk:Access To Modem Configuration helped me and is based on Access To Modem Configuration

In my case I changed the IP of my router to so the modem could still be accessed at even if reset to factory defaults.

Go to Administration -> Commands
In the Edit box enter:

ifconfig vlan1:0
/usr/sbin/iptables -I POSTROUTING -t nat -o vlan1 -d -j MASQUERADE

Click "Save Firewall"
Then "Reboot" from the Management page

IP summary for above commands.
Modem IP:
Router IP:
Go to these IPs for the configuration pages.

Sometimes I would have access to my neighbors' modems as arp requests were repeated by my ISP's DSLAM.
fixed the issue.
Note. Replace MODEM_MAC_ADDRESS_HERE with the MAC address of your modem


albertocasanova said...

What if my modem is on IP?

K. Gates said...

I updated the commands to make using different IPs easier.