Cisco IOS versions 12.4 and later have the capability to directly update your No-IP hostname using a built-in DDNS client. If you have a Cisco router with the latest firmware, this support is already built into it. We offer these examples below for informational purposes only, and recommend that router configuration changes be made by qualified personnel to minimize the risk of losing Internet connectivity or causing other damage to the router.
SUMMARY STEPS
1. 
enable
3. ip ddns update method method-name
4. interval maximum days hours minutes seconds
5. ddns [both]
6. internal
7. http
8. add url
9. remove url
10. exit
11. exit
12. interface interface-type number
13. ip ddns updatehostname hostname
14. ip ddns update method-name
15. exit
Step 1
Enable
Router> enable
Enables privileged EXEC mode.
• Enter your password if prompted.
Step 2
Configure Terminal
Router# configure terminal
Enters global configuration mode.
Step 3
Ip ddns update method method-name
Router(config)# ip ddns update method myupdate
Specifies the update method name and enters DDNS update method configuration mode.
Step 4
Interval maximum days hours minutes seconds
Router(DDNS-update-method)# interval maximum 2 0 0 0
Configures a maximum update interval. The arguments are as follows:
• days—Range is from 0 to 365.
• hours—Range is from 0 to 23.
• minutes—Range is from 0 to 59.
• seconds—Range is from 0 to 59.
Step 5
DDNS [both]
Router(DDNS-update-method)# ddns
Configures DDNS as the update method. The both keyword specifies that both A and PTR RRs will be updated.
Note: You can specify DDNS or HTTP but not both in one step. If you have specified DDNS, you must disable it by using the no ddns command before you can configure HTTP. For the HTTP configuration, see Steps 7,8 and 9.
Step 6
internal
Router(DDNS-update-method)# internal
Specifies that an internal cache will be used as the update method.
Step 7
http
Router(DDNS-update-method)# http
Configures HTTP as the update method and enters DDNS-HTTP configuration mode.
Step 8
add url
Router(DDNS-HTTP)# add http://username:passsword@dynupdate.no-ip.com/nic/update?hostname=<h>&myip=<a>
Configures a URL that should be invoked in order to add or change a mapping between a hostname and an IP address. The following example configures the URL to be invoked to add or change the mapping information using NoIP.com:
•
http://username:passsword@dynupdate.no-ip.com/nic/update?hostname=<h>&myip=<a>.
You have to enter the URL string above. Username is your username and password is your password at the No-IP website. The special character strings and a> will be substituted with the hostname to update and the IP address with which that hostname should be associated, respectively.
Instead of using your No-IP account credentials, you can create and use DDNS Keys. They offer increased account security and better update client compatibility.
Note: Before entering the question mark (?) character, press the control (Ctrl) key and the v key together on your keyboard. This will allow you to enter the ? without the software interpreting the ? as a help query.
Step 9
remove url
Router(DDNS-HTTP)# remove http://username:passsword@dynupdate.no-ip.com/nic/update?hostname=<h>&myip=<a>
Configures a URL that should be invoked in order to remove a mapping between a hostname and an IP address. The URL takes the same form as the add keyword in Step 8.
Step 10
exit
Router(DDNS-HTTP)# exit
Exits to update-method configuration mode.
Step 11
exit
Router(DDNS-update-method)# exit
Exits to global configuration mode.
Step 12
interface interface-type number
Router(config)# interface ether1
Enters interface configuration mode.
Step 13
ip ddns updatehostname hostname
Router(config-if)# ip ddns update hostname yourhost.domain.com
Specifies a host to be used for the updates. The update will associate this hostname with the configured IP address of the interface. The hostname argument specifies the hostname that will receive the updates (for example, No-IP.org).
Step 14
ip ddns update name
Router(config-if) ip ddns update myupdate
Specifies the name of the update method to use for sending Dynamic DNS updates associated with address changes on this interface.
Step 15
exit
Router(config)# exit
Exits to privileged EXEC mode.