Configuring Dynamic DNS for Microbranch

Dynamic DNS Domain Name System. A DNS server functions as a phone book for the intranet and Internet users. It converts human-readable computer host names into IP addresses and IP addresses into host names. It stores several records for a domain name such as an address 'A' record, name server (NS), and mail exchanger (MX) records. The Address 'A' record is the most important record that is stored in a DNS server, because it provides the required IP address for a network peripheral or element. (DDNS) is a feature of APs that allows you to update the hostname and the names of DL3 clients connected to them.

If the ISP Internet Service Provider. An ISP is an organization that provides services for accessing and using the Internet. assigns a dynamic IP address to the AP, the AP loses connectivity due to a change in its public IP address. Similarly, if the dynamically assigned IP address changes for DL3 clients with an AP, which acts as a DHCP Dynamic Host Configuration Protocol. A network protocol that enables a server to automatically assign an IP address to an IP-enabled device from a defined range of numbers configured for a given network.  server, the host is no longer accessible.

Dynamic DNS eliminates these issues by configuring a hostname that provides a consistent approach to access the AP and DL3 clients. The hostname is automatically updated on the DNS server each time the IP address is changed by the ISP.

To enable the dynamic DNS feature for APs and clients in Microbranch, complete the following steps:

  1. In the Aruba Central app, set the filter to a Microbranch group that contains at least one AP.

    The dashboard context for the group is displayed.

  2. Under Manage, click Devices > Access Points.
  3. Click the Config icon.
    The Microbranch group configuration page is displayed.
  4. Complete one of the following steps:
  5. Select the Enable Dynamic DNS check-box to enable the feature and display the DDNS configuration parameters.

    The DDNS configuration parameters are not visible when you select the NATed radio button under the Access Points page. To view the DDNS configuration parameters, you must select the Routed radio button and enter the DNS server IP address by selecting the Specify servers option under DNS Server.

  6. Configure the parameters described in Table 1.
  7. Click Save.

The Domain Name parameter must be passed as part of DHCP where the AP obtains the IP address. For more information, see Configuring Access Points Parameters.

The following table describes the DDNS configuration parameters.

Table 1: Dynamic DNS Configuration Parameters

Mode

Description

Key

Configures a Transaction Signature shared secret key to secure the dynamic updates. The following algorithm names are supported:

  • hmac-md5 (used by default if algo-name is not specified) 
  • hmac-sha1
  • hmac-sha256

Example of Key value: hmac-sha1:arubaddns:<secret key>

NOTE: When the Key value is configured, the update is successful only if the AP and the DNS server clocks are synchronized.

Server IP

Enter the server IP address of the DNS server to which the client updates are sent.

NOTE: This parameter is displayed only in Dynamic DNS page under Services.

Interval

Specify the time interval (in seconds) at which the DNS updates are to be synced to the server. The default time interval is 12 hours (43200 seconds), minimum time interval is 15 minutes, and maximum time interval is 100 days.

NOTE: This parameter is displayed only in Dynamic DNS page under Services.

DDNS Pointer Record (PTR)

Select the check box to enable Pointer Records (PTR) in DDNS client updates. For more information on PTR, see Pointer Records in DDNS Client Updates.

Pointer Records in DDNS Client Updates

Aruba Central supports updating of Pointer Records (PTR) by Dynamic DNS clients, along with the A (host) records in AP and DL3 DHCP profile. A DNS PTR provides the domain name associated with an IP address. The client associated with a domain name, which gets a dynamic IP address from the DHCP server, must ensure that its IP address is always kept up to date (A record). PTR resolves an IP address to a fully-qualified domain name (FQDN Fully Qualified Domain Name. FQDN is a complete domain name that identifies a computer or host on the Internet.) as opposed to the updates of an A record. PTR updates are also called Reverse DNS records. While A (host) record maps the domain name to an IP address, PTR maps the IP address to a hostname. PTR ensures that the IP address of the AP officially connects to the host.

Configuring the PTR is essential if you are using both internal or external mail servers. The PTR adds reliability to server updates and allows the receiving end to check the hostname of the source IP address. This serves as an effective method to safeguard against spammers.

Configuring a DDNS Server Profile

Aruba Central now supports configuring a public DDNS server profile for an AP to which the AP will send updates. A maximum of three DDNS profiles can be configured. However, only one DDNS profile can be assigned to the DL3 DHCP profile and the Instant AP at any given time.

To configure a public DDNS server profile for an AP in Microbranch, complete the following steps:

  1. In the Aruba Central app, set the filter to a Microbranch group that contains at least one AP.

    The dashboard context for the group is displayed.

  2. Under Manage, click Devices > Access Points.
  3. Click the Config icon.
    The Microbranch group configuration page is displayed.
  4. Under Services, click Dynamic DNS.

    The Dynamic DNS page is displayed.

  5. Select a DDNS profile from the DDNS Profile drop-down list.

    The DDNS Profile parameter is not visible when the Enable Dynamic DNS check-box is enabled.

  6. To add a DDNS profile, click the + icon in the DDNS Profile table and specify the following parameters:
  7. Click Save.