Administer your ADSL modem
using BrazilFW or Coyote Linux

You have an ADSL modem connection and would like to administer your modem via it's web interface. If your ADSL modem is acting as a bridge (standard), the only way to do this is connecting a PC directly into the modem. Right? ……Wrong!You landed here via a search but have a router like Linksys or Dlink?

What you do is add a second IP address to the WAN interface and, for PPPoE, you NAT it.

First you need to know what IP address your ADSL modem uses for its web interface. I can't help you there. See your documentation. Next you select an IP address for the WAN interface that is different than the one your ADSL modem uses but is in the same network range. Remember this IP address.
EXAMPLES:
Alcatel modem uses 10.0.0.138 so you use 10.0.0.1
Nortel modem uses 192.168.1.1 so you use 192.168.1.2
Brand X modem uses 192.168.0.1 so you use 192.168.0.2
Brand Z modem uses 192.168.254.254 so you use 192.168.254.1
PROBLEM:
Your modem uses the same IP range as your LAN? See below.

For a temporary solution until the next boot, which is probably what you want, type the first line directly on the BrazilFW/Coyote Linux console. Next, for PPPoE only, type the second line on the console. The mask 255.255.255.0 is represented as /24

ip addr add n.n.n.n/24 dev eth1
iptables -t nat -I POSTROUTING -s x.x.x.0/24 -o eth1 -j MASQUERADE

For a permanent solution simply insert the first line above into /etc/rc.d/rc.local for DHCP or PPPoE plus the second line for PPPoE. Save the file then backup the configuration. Now reboot.Use the Webadmin tool to do this by selecting Configuration Files in the menu on the left then the Local Commands Init Script option.

Your modem uses the same IP range as your LAN

If the IP address of your ADSL modem is in the same range as the one you used for your LAN when you created your BrazilFW (the standard is 192.168.0.1) then you have a problem.There are two choices. Change BrazilFW/Coyote Linux or change the modem IP. Changing the modem will require that you connect a PC directly to the modem and follow the instructions from the manufacturer to change its IP address. Changing Coyote Linux/Brazil Firewall is a little more simple.You can change it from the console, the Webadmin tool by selecting Configuration Files in the left-side menu then the Main Configuration File option, or by editing the file A:\config\coyote.cfg on the floppy.

These are the lines to change. If your setup is DHCP enabled then the two DHCP lines need to change also.

LOCAL_IPADDR='192.168.0.1'
LOCAL_NETMASK='255.255.255.0'
LOCAL_BROADCAST='192.168.0.255'
LOCAL_NETWORK='192.168.0.0'

DHCPD_START_IP='192.168.0.128'
DHCPD_END_IP='192.168.0.191'

Administer a modem using a router like Linksys or D-Link

What you need to do is configure your router as a static router, as opposed to DHCP or PPPoE, and use an IP address in the same range as your ADSL modem; see EXAMPLES above. Then use http://n.n.n.n from your browser.If you have a PPPoE connection it is possible that the configuration userid and password will disappear so you need to know this before making any changes.

These routers all have an option to save the configuration to a file (for later restore). This is an option if you do not remember the userid/password thingy.DO NOT restore from a wireless connection. Your manual warns about this.

The other option is to connect a PC directly to the modem but you would have to disconnect the cable going from the router to the modem and connect your PC to the modem then configure a static IP for your PC. Not the answer you want to hear.