This document explains how to load balance ISA server by configuring NLB on the external NIC on ISA server. Also it explains publishing multiple web sites using server publishing and how it works with NLB.

Objective: To configure ISA server for load balancing and fault tolerance using Network Load Balancing service.

Lab Setup:

Lab has one web server hosting two applications:

http://www.isatest.com

and

http://www.isatest2.com

using different IP addresses:

TCP/IP Settings on Web Server

Configure web server as SecureNAT client by specifying the internal IP of ISA server as gateway address

There are 2 ISA servers connected to external network segment and on internal side to web server through a hub.(see nlb.vsd )

TCP/IP settings on external NIC:

TCP/IP settings on internal NIC:

ISA Servers Configuration

1.Configure NLB on ISA:

1. Install NLB from W2K Advanced Server CD on  ISA server one
2. Click the Start menu, point to Settings, and then open Network and Dial-up Connections.
3. Click the Local Area Connection which connects to public network and check the Network Load balancing box

4. Click Properties
5. Specify the Primary IP address (also called as virtual ip address, this should be same on both the servers)

6. Click on Host Parameters tab
7. Specify the Dedicated IP address (this IP is for network traffic that is not related to client requests to the cluster)
8. Specify the host Priority (this should be unique in the cluster)
9. Click OK twice to close the Local area connection properties box

Note:

If the host priority is same on both servers, NLB will fail. You can do configuration for remote management and port rules according to organization requirements. Those configurations are not explained in this document.

2. Server Publishing Configuration:

a.       Create Protocol Definition for HTTP(IN) and HTTPS(IN)

a.       Right click on Protocol Definitions-> New-> Definition

This will start the New Protocol definition wizard.

b.      Specify the definition name and click on Next

c.       Specify the Port Number, Protocol Type and Direction and click Next

d.      Specify if you want secondary connections and click Next

e.       Click on Finish to finish the protocol definition wizard

b.      Define Protocol Rules

a. Right click on Protocol rule and select New Rule

b. Specify the name for the rule and click Next

c. Select the desired option and click Next

d. Under “Apply This rule to” box select “selected protocol“

e. And under Protocol box, select the protocol you defined earlier and click Next

e. Select the schedule for the rule to apply and click Next

f. Select the desired option and click Next

g. Click on Finish

c.       Create Server Publishing Rule

a. Right Click on Server Publishing Rules and click New Rule

b. Specify the name for the rule and click Next

c. Specify the IP address of internal  Server you want to publish and external IP address of ISA server (this should be the Virtual IP address used for load balancing) and click Next

d. Specify the protocol rule you defined earlier and click Next

e. Select the desired option and click Next

f. Click on Finish

3. Configuring DNS

a.       Create the entry for the web site to resolve to cluster primary IP address. (I used the local host file on the client ).

Configuring Second Host In The Cluster (second ISA Server)

1. Bring up the second ISA server
2. Repeat the steps 1, 2 and 3

Publishing Mutliple Web Sites:

To publish multiple web sites using server publishing requires additional IP address.

Remember you can publish a particular service only once per IP address (Tom’s Book Page no. 654).

To host multiple Web sites with different IP addresses on a Network Load Balancing cluster you need to enter additional virtual IP addresses in the Advanced TCP/IP Settings dialog box, not in the Network Load Balancing Properties dialog box.

• Click the Start menu, point to Settings, and then open Network and Dial-up Connections.
• Click the Local Area Connection for which Network Load balancing is enabled, and then, in the Local Area Connection Status dialog box, click Properties.
• In the Local Area Connection Properties dialog box, click Internet Protocol (TCP/IP), and then click Properties.
• Click Advanced.
• The list under IP Addresses should already contain the host’s dedicated IP address (if you have specified it) and the cluster’s primary IP address. This cluster IP address corresponds to the cluster’s primary IP address that you entered in the Network Load Balancing Properties dialog box under Cluster parameters.
• For each additional virtual IP address that your cluster needs, click Add, and then enter the cluster IP address, followed by the appropriate subnet mask.

Follow the server publishing steps to publish second web site using the second primary cluster IP on ISA