Make sure that you configure the appropriate routing for any interface on which you enable DNS domain lookup so you can reach the DNS server. See the “Information About Routing” section for more information about routing.
Step 1 In the ASDM main application window, choose
Configuration > Device Management > DNS > DNS Client
Step 2 In the DNS Setup area, choose one of the following options:
Configure one DNS server group.
Configure multiple DNS server groups.
Step 3 Click
to display the Add DNS Server Group dialog box.
Step 4 Specify up to six addresses to which DNS requests can be forwarded. The ASA 1000V tries each DNS server in order until it receives a response.
Note You must first enable DNS on at least one interface before you can add a DNS server. The DNS Lookup area shows the DNS status of an interface. A False setting indicates that DNS is disabled. A True setting indicates that DNS is enabled.
Step 5 Enter the name of each configured DNS server group.
Step 6 Enter the IP addresses of the configured servers, and click
to include them in the server group. To remove a configured server from the group, click
Step 7 To change the sequence of the configured servers, click
Step 8 In the Other Settings area, enter the number of seconds between 1 and 30 to wait before trying the next DNS server in the list. The default wait time is 2 seconds. Each time the ASA 1000V retries the list of servers, the timeout time doubles.
Step 9 Enter the number of seconds to wait before trying the next DNS server in the group.
Step 10 Enter a valid DNS domain name for the group of configured servers.
Step 11 Click
to close the Add DNS Server Group dialog box.
The new DNS server settings appear.
Step 12 To change these settings, click
to display the Edit DNS Server Group dialog box.
Step 13 Make your desired changes, then click
to close the Edit DNS Server Group dialog box.
The revised DNS server settings appear.
Step 14 To enable a DNS server group to receive DNS requests, click
Step 15 In the DNS Guard area, to enforce one DNS response per query, check the
Enable DNS Guard on all interfaces
check box. If DNS inspection is enabled, this setting is ignored on the selected interface.
Step 16 Click
to save your changes, or click
to discard those changes and enter new ones.