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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Documentation for this product is no longer updated.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 NextGen Firewall F-Series 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 A llow updates to the server IP address from where the updates are performed.
     dns_allow.png

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
    param_temp.png 

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 the 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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