Configuring a Cisco 67x for DSL Connectivity:

Note: use the hard links if you hit an instruction that is vague -- having a background in programming, I hate re-inventing the wheel

Step 1:
Terminal In to the router and get to a CBOS# prompt. Type the following commands in the order they are presented:

set nvram erase
write
reboot

When its done rebooting, press enter once, and press it again when it asks for a password (you won't have one now). Check the steps in this writeup to get to a CBOS# prompt

Step 2:
If you are in PPP Mode, proceed to step 3. If you are in rfc 1483 (Bridging) mode, proceed to step 6.

Step 3:
If you are in PPP-Dynamic mode, proceed to step 4. If you are in PPP mode, but have a static IP Address, proceed to step 5.

Step 4:
Type the following commands in the order they are presented.

set ppp wan0-0 ipcp 0.0.0.0     
set ppp wan0-0 dns 0.0.0.0     
set ppp wan0-0 login -username- 
set ppp wan0-0 password -password-  
set dhcp server enable          
set nat enable                  
set web disable
set web port 55555
write
reboot

Now let me explain what each command does. The first command tells the router to obtain an IP address from the ISP. The second tells the router to also obtain its DNS server IP addresses from the ISP. The third and fourth set your username and password (respectively) for your ISP. The 5th tells the router to act as a DHCP server, automatically serving IP addresses to the computers on your LAN. The 6th enables NAT, which is used by the router to know where to send traffic between the LAN and the WAN. The seventh disables the web interface, eliminating a vulnerability to the Code Red Worm. The eighth adds further protection from Code Red. The ninth saves the current configuration. The tenth and final command reboots the router so it can make use of the changes. Proceed to step 7.

Step 5:
Type the following commands in the order they are presented.

set dhcp server disable
set interface eth0 address -your static IP-
set interface eth0 netmask -your Subnet Mask-
write
reboot

Proceed to step 7.

Step 6:
Type the following commands in the order they are presented.

set bridging rfc1483 enabled
set bridging management enabled
write
reboot

Proceed to step 7.

Step 7:
If you have a Cisco 675 or a Cisco 678 in CAP Mode, you should now see a solid WAN LNK light. If not, call up your DSL Line support number. If you see a solid WAN LNK light, but are unable to browse, you need to call your ISP. If you have a Cisco 678 and your line is in DMT Mode then proceed to step 9.

Step 9:
Type the following commands in the order they are presented.

set int wan0-0 disable
write
set int wan0-0 vpi 0
set int wan0-0 vci 32
set int wan0-0 enable
write
set int wan0 retrain

"ADSL Physical Link 0 is retraining" should now appear on your screen and your WAN LNK light should flash for a moment then go solid. If not, contact your DSL Provider.

Click Here for more info on the Cisco 67x.