10.0.0.23 - EX13-1 (Exchange server 1)
10.0.0.24 - EX13-2 (Exchange server 2)
Note 1: despite the "13" in the hostname, these servers are Exchange 2010 servers.
Note 2: make sure all the related network nodes are up and running.
10.0.0.32 - VPX NSIP
10.0.0.33 - VPX SNIP
Note 3: these IP addresses were configured on the VPX in the previous blog post.
NetScaler > System > Diagnostics
We have several common diagnostic tools at our disposal, among others PING, TRACEROUTE and a command line interface:
When I have finished, I click on "Run" at the very bottom of the page:
Connectivity is verified for the first Exchange server (EX13-1):
Note : we can also open a command line and enter the commands directly there.
I also verified connectivity with the other Exchange server (success).
Configure load balancing for SMTP traffic (port 25)
Here is a very simple illustration:
Internet -> Firewall -> Load Balancer -> Exchange Server(s)
Load balancing is one of the many features of the NetScaler. We can enable the feature here...
By checking the appropriate box:
We configure load balancing itself here:
NetScaler > Traffic Management > Load Balancing
We need to create:
- Virtual Servers (with a "VIP")
- Monitors (optional - there is always a default monitor that checks the status of the (Exchange) servers but not of the services. It is possible that the server is available (functional) but the actual services are stopped. Therefore, we can optionally configure a monitor if we want to fine-tune the awareness of service availability).
I will follow the order of creation used the in Citrix training course (see reference in previous blog post), although creating the items above in a different order is possible.
Enter the necessary details and click on Create:
I then add a second server (note the first server we created in the server list):
Now we have designated our two Exchange servers:
Next we must configure a "service" (in this case for SMTP) associated with each of the servers:
Configure a SMTP service for each of the Exchange servers as shown below
Here are the services we have configured:
For the virtual server, we provide the details entered in the screenshot below. The IP address is the address that clients will access for the service in question (as opposed to the IP address of the Exchange servers themselves). In my case, the "client" for SMTP connections is the perimeter firewall that will forward email from the outside to this IP address (10.0.0.36):
Once we click OK, we will arrive at this page where we need to bind the two services (each linked to one of the Exchange servers) to the virtual server:
We click on "No Load Balancing Virtual Server Service Binding" (see above) and then "Click to select" services:
Select both of the services we configured earlier...
And click on "Bind":
And select ROUNDROBIN as the Load Balancing Method:
The result should look like this: