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Barracuda Link Balancer


As of 1st March 2019, all new sales for the Barracuda Link Balancer product will cease. Only renewals of software and hardware subscriptions for a maximum of one year is available for a limited time. 1st March 2020: All Barracuda Link Balancer sales will cease; neither new sales nor any renewals will be available. If you currently hold a maintenance and support contract, you will continue to receive our award-winning support and services until your contract expires.

How to Create NAT Rules

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1:1 NAT rules are executed only if the Barracuda Link Balancer firewall is enabled or if a WAN link has the NAT setting enabled.

If an internal server needs to receive traffic from more than one WAN link, create a 1:1 NAT or port forwarding rule (see: How to Create Port Forwarding Rules) for each WAN link. If you then create a DNS domain, the Barracuda Link Balancer will automatically generate A records based on the Port Forwarding and 1:1 NAT rules.

Before you Begin:

The WAN IP address is the IP address used for general purpose NAT. If necessary, add the publicly accessible IP addresses to the configuration.

  1. Log into the Barracuda Link Balancer Web Interface.
  2. Go to the Basic > Links page.
  3. Click the + sign to expand and edit the WAN link. 
  4. Add Additional IP Addresses which are the external IP addresses that are eligible to be used for 1:1 NAT.
  5. Click Save Changes.

Create a 1:1 NAT Rule

  1. Go to the FIREWALL > NAT page.
  2. Enter a descriptive name in the Rule Name field.
  3. From the Listen Link drop down field, select the WAN link to use.
  4. If desired, enter the hostname or the fully qualified domain name associated with the IP addresses in the Hostname field.

    If you create a domain on the Services > Authoritative DNS page the Barracuda Link Balancer searches for matching domain names in the Port Forwarding and 1:1 NAT rules. For every match, a DNS A record is created linking this hostname to its external and internal IP addresses. You can enter a fully qualified domain name (e.g. www.example.com. with or without the ending dot) or a hostname (e.g. www.example.com). If a hostname is entered, it is considered to be part of the default domain that is specified on the Basic > IP Configuration page.

  5. In the Forward IP field, type the private static IP address of the server which must be reachable from the LAN of the Barracuda Link Balancer. Or, if creating a DNAT rule for a link, type a static IP address reachable through a WAN link (usually, the firewall IP address reachable through WAN1).
  6. Make sure that you clear the Disable check box to enable the rule.
  7. To write an entry in the Firewall Log whenever this rule is executed, select the Log check box.
  8. Select the Auto-create firewall rule check box to automatically create an inbound firewall rule to accept traffic for the external IP address.
  9. Click Add.
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