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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 Add an Additional ISP Link in Firewall Disabled Mode

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This article provides step-by-step instructions for adding an additional ISP link (ISP #2) that will be connected to WAN2, while the existing ISP (ISP #1) remains connected to WAN1. Adding more than one additional ISP works identically.

To add a secondary ISP link, complete the following steps.

Step 1: Add the DNS of the Secondary ISP to the Local Network Configuration

You must make the DNS settings of the new ISP available to hosts within the local network. Otherwise, DNS queries will be routed to ISP #1 where they will be rejected due to access and flood control protection. DNS resolution would be impossible and the Internet would be unreachable from the local network.

Add the DNS servers for ISP #2 to the configuration of your internal network. For backup, you may also add the IP addresses of open domain name servers at the end of the list.

Step 2: Assign a New IP Address from ISP #2 to WAN2

Do not change the network configuration for the existing firewall. Assign an additional IP address from ISP #2 to WAN2.

The Barracuda Link Balancer does not do address translations on this link. At the IP layer, the firewall and the ISP devices ignore the Barracuda Link Balancer. However, at the MAC layer, this may not be the case.

Step 3: Clear the ARP Cache on the Router for ISP #2

The Barracuda Link Balancer will use the MAC address of WAN2 for packets sent to the router (while using the respective source IP address of the firewall) and packets going into the local network. To make sure that neighboring devices use the correct MAC address, you must reboot the router for ISP #2 to clear its ARP cache.

For help with rebooting the router, contact Barracuda Networks Technical Support to help you configure the Barracuda Link Balancer to use the MAC address for the firewall interface when communicating with the router for PoC situations.

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