Configuring Dynamic DNS
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Step 1 |
ciscoasa(config)# ddns update method ddns-2 |
Creates a DDNS update method ddns-2 that dynamically updates DNS resource records (RRs). |
Step 2 |
ciscoasa(DDNS-update-method)# ddns both |
Specifies that the client updates both the DNS A and PTR resource records (RRs ). |
Step 3 |
ciscoasa(DDNS-update-method)# interface Ethernet0 |
Configures an interface Ethernet 0and enters interface configuration mode. |
Step 4 |
ddns update [
method-name | hostname hostname]
ciscoasa(config-if)# ddns update ddns-2 ciscoasa(config-if)# ddns update hostname asa.example.com |
Associates the the DDNS method ddns-2 with the Ethernet0 interface and an update hostname. |
Step 5 |
dhcp-client update dns [server {both | none}]
ciscoasa(config)# dhcp-client update dns server none |
Configures the DHCP client to request that the DHCP server perform no updates. |
Step 6 |
ciscoasa(if-config)# ip address dhcp |
Uses DHCP to obtain an IP address for the interface. |
Step 7 |
dhcpd update dns [both] [override] [interface srv_ifc_name]
ciscoasa(if-config)# dhcpd update dns both override |
Configures DHCP server to override the client update requests. |
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Step 1 |
ciscoasa(config)# interface Ethernet0 |
Configures an interface Ethernet 0. |
Step 2 |
dhcp-client update dns [server {both | none}]
ciscoasa(config-if)# dhcp-client update dns both |
DHCP client requests that the DHCP server update both the DNS A and PTR resource records. |
Step 3 |
ddns update [
method-name | hostname hostname]
ciscoasa(config-if)# ddns update hostname asa |
Configures the DHCP client on interface Ethernet 0. |
Step 4 |
dhcpd update dns [both] [override] [interface srv_ifc_name]
ciscoasa(config-if)# dhcpd update dns |
Configures DHCP server to perform DDNS updates. |
Step 5 |
dhcpd domain domain_name [interface if_name]
ciscoasa(config-if)# dhcpd domain example.com |
Defines the DNS domain name for DHCP clients. |
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Step 1 |
ciscoasa(config)# ddns update method ddns-2 |
Creates a DDNS update method ddns-2 that dynamically updates DNS resource records (RRs). |
Step 2 |
ciscoasa(DDNS-update-method)# ddns |
Specifies a dynamic DNS (DDNS) update method. |
Step 3 |
ciscoasa(DDNS-update-method)# interface Ethernet0 |
Configures an interface Ethernet 0. |
Step 4 |
dhcp-client update dns [server {both | none}]
ciscoasa(config-if)# dhcp-client update dns |
Configures the update parameters that the DHCP client passes to the DHCP server. |
Step 5 |
ddns update [
method-name | hostname hostname]
ciscoasa(config-if)# ddns update ddns-2 ciscoasa(config-if)# ddns update hostname asa |
Associates the the DDNS method ddns-2 with the Ethernet0 interface and an update hostname. |
Step 6 |
dhcpd update dns [both] [override] [interface srv_ifc_name]
ciscoasa(if-config)# dhcpd update dns |
Configures DHCP server to perform DDNS updates. |
Step 7 |
dhcpd domain domain_name [interface if_name]
ciscoasa(config-if)# dhcpd domain example.com |
Defines the DNS domain name for DHCP clients. |
Dynamic DNS provides address and domain name mapping so that hosts can find each other, even though their DHCP-assigned IP addresses change frequently. The DDNS name and address mapping are stored on the DHCP server in two resource records: the A RR includes the name-to-IP address mapping, while the PTR RR maps addresses to names. Of the two methods for performing DDNS updates—the IETF standard defined by RFC 2136 and a generic HTTP method—the ASA supports the IETF method in this release.
The Dynamic DNS pane shows the configured DDNS update methods and the interfaces that have been configured for DDNS. By automatically recording the association between assigned addresses and hostnames at pre-defined intervals, DDNS allows frequently changing address-hostname associations to be updated regularly. Mobile hosts, for example, can then move freely on a network without user or administrator intervention.
To configure dynamic DNS client settings for updating the DNS server, perform the following steps:
Step 1 In the ASDM main application window, choose Configuration > Device Management > DNS > Dynamic DNS .
Step 2 Click Add to display the Add Dynamic DNS Update Method dialog box.
Step 3 Enter the name for the DDNS update method.
Step 4 Specify the update interval between DNS update attempts configured for the update method in days, hours, minutes, and seconds.
- Choose the number of days between update attempts from 0 to 364.
- Choose the number of hours (in whole numbers) between update attempts from 0 to 23.
- Choose the number of minutes (in whole numbers) between update attempts from 0 to 59.
- Choose the number of seconds (in whole numbers) between update attempts from 0 to 59.
These units are additive. That is, if you enter 0 days, 0 hours, 5 minutes and 15 seconds, the update method tries an update every 5 minutes and 15 seconds for as long as the method is active.
Step 5 To store server resource record updates that the DNS client updates, choose one of the following options:
- Both the A resource record and the PTR resource record.
- The A resource records only.
Step 6 Click OK to close the Add Dynamic DNS Update Method dialog box.
The new dynamic DNS client settings appear.
Step 7 To change these settings, click Edit to display the Edit Dynamic DDNS Update Method dialog box. When you edit an existing method, the Name field is display-only and shows the name of the selected method for editing
Step 8 Make your desired changes, and then click OK to close the Edit Dynamic DDNS Update Method dialog box.
The revised dynamic DNS client settings appear.
Step 9 To remove configured settings, choose the settings from the list, and then click Delete .
Step 10 To add DDNS settings for each interface configured for DDNS, click Add to display the Add Dynamic DNS Interface Settings dialog box.
Step 11 Choose the interface from the drop-down list.
Step 12 Choose the update method assigned to the interface from the drop-down list.
Step 13 Enter the hostname of the DDNS client.
Step 14 To store resource record updates, choose one of the following options:
- Default (PTR Records) to specify that the client request PTR record updating by the server.
- Both (PTR Records and A Records) to specify that the client request both the A and PTR DNS resource records by the server.
- None to specify that the client request no updates by the server.
Note DHCP must be enabled on the selected interface for this action to take effect.
Step 15 Click OK to close the Add Dynamic DNS Interface Settings dialog box.
The new dynamic DNS interface settings appear.
Step 16 To change these settings, click Edit to display the Edit Dynamic DNS Interface Settings dialog box.
Step 17 Make your desired changes, and then click OK to close the Edit Dynamic DNS Interface Settings dialog box.
The revised dynamic DNS interface settings appear.
Step 18 To remove configured settings, choose the settings from the list, and then click Delete .
Step 19 Click Apply to save your changes, or click Reset to discard them and enter new ones.