Use this window to create and configure a DNS (Domain Name System) group object. This object represents a DNS client on the SBC capable of communicating with external DNS servers to resolve domain names.
Note
Each signaling port within an Address Context must use a unique IP address and port number combination.
Note
The SBC 52x0 and SBC 7000 systems support creating IP Interface Groups containing sets of IP interfaces that are not "processor friendly" (i.e. carried on physical Ethernet ports served by separate processors). However, restrictions exist regarding the usage of such Interface Groups.
(This ability does not apply to the SBC 51x0 and SBC 5400 systems which have only two physical media ports. IP interfaces from the two physical ports may be configured within the same IP Interface Groups without restriction.)
For complete details, refer to Configuring IP Interface Groups and Interfaces.
Note
The SBC Core supports up to eight DNS servers per DNS group. The SBC 5xx0/5400/7000 platforms support up to 2,048 DNS Groups system-wide. SBC SWe supports up to 128 DNS Groups. See SBC Provisioning Limits for additional provisioning limitations.
To View DNS Groups
On the SBC main screen, go to Configuration > System Provisioning > Category: Base Provisioning > DNS > Servers > DNS > DNS Group or
All > Address Context > DNS Group
The DNS Group window is displayed. Select an Address Context to show only the DNS Groups configured within that address context.
DNS Group
To Create a DNS Group
To create a new DNS Group:
In the DNS Group window, select the Address Context within which you want to create the DNS Group.
Click New DNS Group. The Create New DNS Group window opens.
Create New DNS Group Window
- Use the following table to configure the options and then click Save.
DNS Group Parameters
Parameter | Description |
|---|---|
Name | A name for the DNS Group of up to 23 characters. This field is mandatory. |
Type | Specifies the interface type to usefor DNS queries. The options are:
Based on the type chosen additional options open. |
Transport | The transport protocol to use to communicate with DNS servers.
|
Mgmt Interface | Name of management interface group to use when using management interfaces. Note: This field appears only when the Type selected is Mgmt. |
IP Interface | Name of IP interface group to use when using packet interfaces. Note: This field appears only when the Type selected is IP. |
Use Configured Dns Server | With the option disabled, the SBC stores "Authoritative" NS records received in Domain Name System (DNS) query responses and uses them for locating a closer DNS server for subsequent DNS queries. There are cases where an “Authoritative” server may not be directly reachable from the SBC, or its query responses are blocked by IP ACL rules configured on the SBC. This causes DNS queries to fail and subsequent call failures. With the option enabled, the SBC supports using the configured DNS for external DNS queries within that DNS group. It sends the DNS queries to the DNS server in the DNS group and ignores Authoritative servers.The options are:
|
Edns Support | Enable flag to support Extension mechanisms for Domain Name Systems (EDNS) for statically configured and dynamically learned DNS servers. The options are:
|
To Edit a DNS Group
To edit a DNS Group object:
- Click the radio button next to the DNS Group you want to edit. The Edit DNS Group window opens.
- Modify the options as needed and click Save.
To Delete a DNS Group
To delete a DNS Group:
- Click the radio button next to the DNS Group that you want to delete.
- Click the X Delete icon at the end of the highlighted row.
- Confirm the deletion when prompted.
Note
Before deleting a DNS group, first delete the DNS local record names and DNS server in that group.
DNS Group Commands
Use DNS Group commands to perform manual actions against a configured DNS Group.
To use DNS Group commands for any specific DNS Group, click the radio button next to the specific DNS Group. The DNS Group Commands window is displayed at the bottom of the window.
DNS Group Commands
Clear Cache
Use the Clear Cache command to clear the cache of a specified record.
Choose Clear Cache in the Commands list and click Select. A clearCache dialog box opens.
Clear Cache
- In Domain Name, enter the name of the domain record you want to clear from the cache.
- In Record Type, select the type of DNS record to clear. The options are:
- A
- Aaaa
- Ns
- Srv
- Naptr
- Default (default)
- Click clearCache.
DNS Server Reset
Use the DNS Server Reset command to reset all DNS server statistics.
- Choose DNS Server Reset in the Commands list and click Select. A dnsServerReset dialog box opens.
- Click dnsServeReset.
- Confirm the action when prompted.
Query
Use the Query command to send a DNS query to a specified server.
Choose Query in the Commands list and click Select. A query dialog box opens.
Query Command
- Use the following table to enter parameters for the query and click query.
Query Parameters
| Parameter | Description |
|---|---|
| DNS Server | Enter a DNS Server to be used to perform lookup. |
| FQDN | Enter the domain to be looked up. |
| Record Type | Specifies the type of DNS records.
|
Update Ttl
Use the Update Ttl command to to update the TTL (time to live) value in the cache for a specified record.
Choose Update Ttl in the Commands list and click Select. An update Ttl dialog box opens.
Update Ttl Command
- Use the following table to specify the record to update and click updateTtl.
Update Ttl Parameters
| Parameter | Description |
|---|---|
| FQDN | Enter FQDN whose record to update in the cache. |
| Record Type | Specifies the type of DNS records.
|
| Ttl | Enter a new TTL value. |
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