DSR Load Balance
Direct Server Return Load Balancing
Direct server return load balancing concept
Standard Load Balancing
In standard deployment all traffic goes through load balancer.
Direct Server Return
In direct server return only syn packet is traveling via load balancer. Syn Ack packet goes to client directly.
All server must have loopback interface with LB IP address
All application on the server listen for connections on LB IP address (lo interface)
Firewall - Makes DNAT to forward syn packet to LB
LB forward packet to server with LB IP address as destination IP
Load balancer performance improvement
No offloading options
No cache options