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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.

Configuring the Barracuda Link Balancer for Two Independent ISP Links and Firewalls

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This article provides steps for inserting a Barracuda Link Balancer into an existing network so that the LAN is fed by two independent Internet links through two independent firewalls.

Example Setup and IP Addresses

The following diagram shows the example configuration used in this article:


 This example uses these IP addresses and subnets:

1Internet Router #1
2Internet Router #2
2Firewall #1 external
3Firewall #1 internal
5Firewall #2 external
6Firewall #2 internal
7Core Switch

Step 1. Connect and Configure the LAN and WAN Links on the Barracuda Link Balancer

  1. On the Barracuda Link Balancer connect Switch #1 to the LAN port.
  2. On the Barracuda Link Balancer, connect router #1 to the WAN1 port, and router #2 to the WAN2 port.
  3. Go to the BASIC > Links page, and configure the IP address, netmask, gateway, DNS, and health check settings for both WAN links.

Step 2. Connect and Configure the Firewalls

Connect Switch #1 to firewall #1 and firewall #2.

In this example, the external IP addresses are for firewall #1 and for firewall #2. The internal IP addresses are for firewall #1 and for firewall #2.

Usage Modes

This setup provides the following gateway IP addresses:

  • for clients to access a cumulative Internet uplink using both ISPs filtered separately through both firewalls.
  • for clients to access ISP #1 filtered by firewall #1.
  • for clients to access ISP #2 filtered by firewall #2.
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