Specifications

24 Barracuda Load Balancer Administrator’s Guide
flat network and have to access databases on other subnets, or if the Real Servers are on
the same subnet as the Barracuda Load Balancer and the configuration cannot be
changed, then DSR is recommended.
• DSR can assist in optimizing Windows to Windows communication between Real
Servers. If you have Real Servers on active Windows domains where the domain
controllers are not on the same subnet, and Layer 7 features are not required, use DSR.
See Figure 2.6 for an example of this type of layout.
The following table describes the advantages and disadvantages of deploying your Barracuda Load
Balancer in Direct Server Return mode.
Figure 2.6: Sample Direct Server Path network layout
Advantages Disadvantages
Ideal for high-bandwidth requirements such
as content delivery networks
Requires flat network topology
Keeps existing IP addresses of Real Servers Requires non-ARPing loopback adapter on Real Servers
IP persistence on Layer 4 only
Not compatible with SSL offloading or cookie
persistence.