How to configure Dynamic DNS in Cisco Routers?



I was encouter a lot of problem and headache when I had to do the Cisco Router installation and configuration with Dynamic DNS.

So now, I'd like to share my real world experience in configuring Dynamic DNS configuration for Cisco Router.

OK. Let's start through now. Assume connect to Router through and you're in IOS Windowds. Please follow below configuration,

Router>enable

Router#configure terminal

Router(config)# ip ddns update method method-name

(Specifies the update method name and enters DDNS update method configuration mode. Example:Router(config)# ip ddns update method DynDNS)

Router(DDNS-update-method)# interval maximum days hours minutes seconds

(Configures a maximum update interval. Example: Router(DDNS-update-method)# interval maximum 2 0 0 0)

Router(DDNS-update-method)# ddns

(Configures DDNS as the update method.)

Router(DDNS-update-method)# internal

(Specifies that an internal cache will be used as the update method.)

Router(DDNS-update-method)# http

(Configures HTTP as the update method and enters DDNS-HTTP configuration mode.)

Router(DDNS-HTTP)# add http://username:password@members.dyndns.org/nic/update?system=dyndns&hostname=&myip=

(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 dyndns.org:
http://username:password@members.dyndns.org/nic/update?system=dyndns&hostname=&myip=
You have to enter the URL string above. username is your username and password is your password at the dyndns.org website.
The special character strings and will be substituted with the hostname to update and the IP address with which that hostname should be associated, respectively.
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.)


Router(DDNS-HTTP)# remove http://username:password@members.dyndns.org/nic/update?system=dyndns&hostname=&myip=

(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 above step.)


Router(DDNS-HTTP)# exit
Router(DDNS-update-method)# exit

Router(config)# interface interface-type number

(Enters interface configuration mode that link to Internet or ISP Provider.)

Router(config-if)# ip ddns update hostname hostname

(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, dyndns.org).
 Example: Router(config-if)# ip ddns update hostname abc.dyndns.org)


Router(config-if) ip ddns update name

( Specifies the name of the update method to use for sending Dynamic DNS updates associated with address changes on this interface.
  Example: Router(config-if) ip ddns update DynDNS)

Router(config)# exit


OK. That's it. Now you done the configuration for Dynamic DNS. But don't forget to save the configuration.

Below is complete sample configuration for your reference.

Router> enable
Router# configure terminal
Router(config)# ip ddns update method DynDNS
Router(DDNS-update-method)# interval maximum 2 0 0 0
Router(DDNS-update-method)# ddns
Router(DDNS-update-method)# internal
Router(DDNS-update-method)# http
Router(DDNS-HTTP)# add http://username:password@members.dyndns.org/nic/update?system=dyndns&hostname=&myip=
Router(DDNS-HTTP)# remove http://username:password@members.dyndns.org/nic/update?system=dyndns&hostname=&myip=
Router(DDNS-HTTP)# exit
Router(DDNS-update-method)# exit
Router(config)# interface FastEthernet0
Router(config-if)# ip ddns update hostname abc.dyndns.org
Router(config-if) ip ddns update DynDNS
Router(config)# exit


There is some option you can use for specific requirement but I didn't show because of the above configuration is commonly used in most condition in real world.

And the configuration could be a bit differ depends on option and Dynamic DNS Service that you gonna use. Please be aware this and check on Support at Service Provider if you need in case.

I hope you will understand this configuration and get easy for Dynamic DNS setup in Cisco Router as well.

May you all be happy.
(Be knowledgeable, pass it on then)


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