BROCADE IP PRIMER

Chapter 15: Server Load Balancing (SLB)To get a high level of which real servers are bound to virtual servers and whattheir current state is, use the third helpful command:SLB-ServerIron#show server bindBind infoVirtual server: wwwStatus: enabled IP:1.2.3.4http -------> rs1: 10.1.1.11, http (Active)rs2: 10.1.1.12, http (Active)Notice that the output of this command shows the virtual server, the name,and the VIP address. It then details each of the bound real servers, their nameand address, the bound port, and finally, the current state of the bound port.Configuring Source NATLet's look back at Chapter 3. Source NAT is used when the load-balanced serversare not directly connected to the load balancer (or when all traffic to andfrom the real servers is not routed through the load balancer). The load balancercan still hand off to the real server, but the return traffic must comeback through the load balancer to be properly translated to the VIP. To do this,Source NAT makes the packets that go to the real server appear to come fromthe ServerIron itself. The real server returns the packets to the ServerIron, andthe ServerIron translates it to the proper VIP and sends it back to the outsideclient.The first thing that needs to be configured is a “source-ip” address. This is avirtual address that you assign to the ServerIron so that it can reach theremote servers for health checks and for passing traffic. This will also be the IPaddress that appears as the source address for traffic that is passed to thereal server (that is using Source NAT). The ServerIron limits the number ofsource IPs to 64.SLB-ServerIron#conf tSLB-ServerIron(config)#server source-ip 10.20.30.3255.255.255.0 10.20.30.1Notice that we've specified an IP address, subnet mask, and a default gateway.Next, we need to enable Source NAT. This can be either enabled globallyor locally. If you enable it globally, it will affect all real servers. Use the followingcommand from within the Global config:SLB-ServerIron#conf tSLB-ServerIron(config)#server source-natIf you have some real servers you would like to use Source NAT, and othersthat you do not, you'll want to enable Source NAT locally. This is done in thereal server sub-config:SLB-ServerIron#conf tSLB-ServerIron(config)#server real rs1SLB-ServerIron(config-rs-rs1)#source-natThat's all there is to it. You are now using Source NAT.342 Brocade IP Primer