Here is most of important configuration for emergency backdoor link thru AUX port. As a network support engineer, it would be number 1 configuration stuff need to memorize and use it all the time.

Once your client said my network is down, especially WAN link, what you can do in remote ?. Drive or flight ? Oh man you know how you feel.

Cisco devices provide AUX port to save your time and job position(?). Buyging cheap modem and set this one up. It would release a lot of worries and fears(?).

Let see check the below.

1. Buy modem(of cause external) and If you have old router, buy RS-232 cable(32pin to 9pin)

2. Have phone # to use this back door emergency line

3. Connnect cable between Modem and Cisco device

4. Configure Cisco device ( In this example, using Cisco 3660 router)

Line configuration

 

line aux 0
exec-timeout 0 0
modem InOut
modem autoconfigure type usr_sportster
or modem autoconfiguration discovery <-- if not sure what kinds of modem connected.
transport input all
speed 115200

 

Logical Interface configuration

- Find line # first

interface Async225
ip address 192.168.1.10 255.255.255.0
encapsulation ppp
dialer in-band
dialer idle-timeout 60
async mode interactive
peer default ip address 192.168.1.11
ppp authentication chap
end

---

Please share this article with ;