Barracuda Networks Load Balancer FAQ

Why use a load balancer?

Deploying a load balancer helps achieve constant server availability as well as simple scalability. It allows administrators to easily perform server maintenance, and a painless way to add systems to the Load Balanced server farm.

How easy is the Barracuda Load Balancer to configure?

The Barracuda Load Balancer provides the industry’s easiest configuration via an intuitive Web interface. Normal setup can be performed in a few simple steps. Most customers are able to set up their load balancing configurations within 10 minutes.

Does the Barracuda Load Balancer have any security features?

The Barracuda Load Balancer has a built-in Intrusion Prevention System (IPS), as well as Access Control Lists (ACL) and a SSL-secured Web user interface.

How does the Barracuda Load Balancer's internal IPS work?

The Barracuda Load Balancer's integrated Intrusion Prevention System uses a refined set of constantly updated vulnerability definitions to automatically block malicious attacks as they happen. When an attack is detected, the Barracuda Load Balancer simply sends a TCP RESET in both directions (server and client).

What protocols does the Barracuda Load Balancer support?

The Barracuda Load Balancer supports any TCP or UDP service.

How many real servers does the Barracuda Load Balancer support?

The entry-level Load Balancer (model 240) supports up to 25 real servers, while a higher-end system (model 440) can support up to 250 real servers.

Do I need any additional hardware to be able to load balance?

You may need additional switches depending on your deployment configuration. The Barracuda Load Balancer includes two ports: a WAN and LAN interface.

When should I use Layer 4 IP persistence?

Client IP persistence is useful in applications which require session persistence. For example, Web-based shopping carts or any service which requires a login and/or uses multiple requests would be a good candidate for IP persistence.

Is it easy to add new servers to the server farm?

Real servers can be added to the configuration with one step using the Barracuda Load Balancer's Web interface.

What can I use the Barracuda API for?

Available on the Barracuda Load Balancer 440, the Application Programming Interface (API) facilitates scripted implementation of any setting available in the Web interface. Most often used by ISPs and MSPs, this allows for load balanced services (including intrusion prevention) to be integrated into existing customer build scripts.

What is the Service Monitor?

The Service Monitor actively watches all real servers, their connections, and performance.

How does the Barracuda Load Balancer handle failed servers?

When the Service Monitor detects a downed real server, the Barracuda Load Balancer automatically removes the server from the load-balanced cluster. If the real server again becomes available, it will automatically place the server back in the distribution queue.

Real servers may also be placed in “maintenance mode,” which gracefully removes them from any bound services in order to facilitate server maintenance or upgrades. When the real server is again available, administrators simply enable the server through the Barracuda Load Balancer's Web interface.

What protocols and applications are supported by the Barracuda Load Balancer?

The Barracuda Load Balancer works with any TCP/UDP service or application.

What sort of configuration flexibility does the Barracuda Load Balancer offer?

The Barracuda Load Balancer supports route-path, bridge-path, and direct server return configurations. Server weights are fully configurable along with flexible scheduling options such as round-robin and least connections.

What is Direct Server Return?

Ideal for high bandwidth and content delivery networks, Direct Server Return is a load balancing configuration which facilitates responses to server requests being delivered directly to the network rather than being routed back through the load balancer. This configuration can be used to deliver 10x bandwidth throughput versus route-path or bridge-path modes.

Configuration of Direct Server Return is easy, and uses the built-in non-ARPing loopback adapter which is included in allWindows and Linux servers.

What is a VIP (Virtual IP)?

The VIP, or Virtual IP Address, is the IP address that is used to access load-balanced services.

What is a Real Server?

A “Real Server” is the actual physical server which holds the content or runs the application that is delivered to the client via the Barracuda Load Balancer.

What is a Service?

A “Service” is the combination, or binding, of a Virtual IP address, ports, and real server IP addresses.