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Barracuda CloudGen Firewall

This Firmware Version Is End-Of-Support

Documentation for this product is no longer updated. Please see End-of-Support for CloudGen Firewall Firmware for further information on our EoS policy.

How to Configure DHCP with Dynamic DNS

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Configure dynamic DNS updates for the Barracuda CloudGen Firewall DHCP service. The DDNS update style is evaluated once after reading the dhcpd.conf file, not each time a client is assigned an IP address. As a result, the same DNS update style is used for all clients.

Before You Begin

Step 1. Configure the DNS Zones

Configure DNS zones for your clients. If a forward and a reverse lookup must be done, a valid zone must be configured where updates are allowed. A reverse zone is not required if only a forward lookup should be done.  

  • In the advanced zone properties of the DNS zones used, set the parameter Allow updates to the server IP address from where the updates are performed.

For more information, see How to Configure DNS Zones.

Step 2. Create a DHCP Subnet

Create a DHCP subnet for the clients that should receive DDNS updates. For more information, see How to Configure DHCP Subnets and Address Pools.

Step 3. Create a Parameter Template

Create a DHCP parameter template for the subnet the clients reside in:

  • In the Dynamic DNS Parameters settings, set Do Fwd Updates to true.
  • For dynamic DNS to work, you must also enter the DDNS Domainname. 

For more information, see How to Configure DHCP Parameter Templates.  

Step 4. Configure Dynamic DNS

  1. Go to CONFIGURATION Configuration Tree > Box > Virtual Servers >  your virtual server  > Assigned Services > DHCP > DHCP Enterprise Configuration.
  2. In the left menu, expand the Configuration Mode section and click Advanced View.
  3. In the left menu, select Dynamic DNS.
  4. Click Lock.
  5. Select whether to use a DNS Update Scheme.
    • When selecting interim, choose an option from the Client Updates list.

      The DHCP server does not necessarily always update both the A and the PTR records. The FQDN (fully qualified domain name) option includes a flag that, when sent by the client, indicates that the client wishes to update its own A record. In that case, the server can be configured either to honor the client's intentions or ignore them. This is done with either statement "allow client-updates" or "ignore client-updates". By default, client updates are ignored.

  6. (optional) In the Zone Keys table, click + and add the HMAC-MD5 keys for the DNS zones.
  7. In the DNS Zones table, click + and add the DNS zones. 
  8. Specify the Zone Type. You can select:
    • Forward – (default) The hostname is looked up.
      • Enter the network of the forward lookup in the Forward Zone Name field.
    • Reverse – The IP address is looked up.
      • Enter the network of the reverse lookup in the Reverse Lookup Net/Netmask fields.
    • Both – IP address and hostname are looked up.
      • Enter the network of the forward and reverse lookup in the Forward Zone Name and Reverse Lookup Net/Netmask fields.
  9. Enter the DNS Server IP address.
  10. Select the Authentication Key for the zone that was entered in the Zone Keys table.
  11. (optional) Click + and add additional DNS zones.
  12. Click OK.
  13. Click Send Changes and Activate.
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