Recommended Settings for a Generic Implementation of a NetScaler Appliance

The following sections contain the recommended settings for a generic implementation of some features of a NetScaler appliance:

• Modes
• Features
• Global System Settings
• HTTP Parameters
• SNMP Alarms
• Network Interfaces
• General Best Practices

Modes

To configure the modes on an appliance, complete the following procedure:

1. Expand the System node of the Navigation pane on the appliance.

2. Select the Settings node.

3. In the details pane, under Modes and Features, click Configure modes.

4. Select the Fast Ramp option.
   Note: With Fast-Ramp enabled the NetScaler starts with the congestion window of the freshest server connection. For more information refer to Citrix Blog.

5. Clear the Layer 2 Mode option.
   Note: Select this mode if servers are connected directly to the appliance or if the appliance is used as a transparent bridge.

6. Select the Use Source IP option.
   Note: Select this mode only if an application requires the source IP address.

7. Clear the Client Keep-Alive option.
   Note: Applications can stop working due to optimization. Select this option only when there are performance issues.

8. Clear the TCP Buffering option.
   Note: If the network does not support Window Scaling and there are performance issues, select this option.

9. Clear the MAC Based Forwarding option.
   Note: If you are using a one-arm configuration, then select this option.

10. Select the Use Subnet IP option.
    Note: Always select this option unless specific requirements of the network setup do not require it.

11. Select the Path MTU Discovery option. This mode helps avoid the fragmentation of packets.

12. Clear the Static Route Advertisement option.
    Note: If you are using the dynamic routing feature, select this option.

13. Clear the Direct Route Advertisement option.

14. Clear the Intranet Route Advertisement option.

15. Clear the Ipv6 Static Route Advertisement option.

16. Clear the Ipv6 Direct Route Advertisement option.

17. Clear the Bridge BPDUs option.

Features

For information on the features available and how to enable them on NetScaler, refer to CTX122942 - How to Activate Various Features and Modes of a NetScaler Appliance.
Note: Enabling features impacts the performance of the NetScaler appliance. Enable only the features that you want to use.

Global System Settings

To configure the global system settings on an appliance, complete the following procedure:

1. Expand the System node of the Navigation pane on the appliance.

2. Select the Settings node.

3. Click the Change global system settings link on the Settings page.

4. Select the Window Scaling option.
   Note: Clear the Window Scaling option only if it is not supported by the network.
   In NetScaler 10.5, 11.0 and 11.1 builds the "Window Scaling" option is under System > Settings > Change TCP Parameters.

5. Select the Selective Acknowledgment option.
   Note: Clear this option only if the Window Scaling option is clear.
   In NetScaler 10.5, 11.0 and 11.1 builds the "Selective Acknowledgment" option is under System > Settings > Change TCP Parameters.

6. Select the Use Nagle’s algorithm option. In NetScaler 10.5, 11.0 and 11.1 builds the "Nagle’s algorithm" option is under System > Settings > Change TCP Parameters.
   Points to Note:
   - Select this option for heavy flow of small packets. Not recommended for ICA traffic.
   - Nagle’s algorithm is disabled in default TCP profile. However, in a custom TCP profile it is enabled currently and this will be fixed in an upcoming release . Custom profiles have to be explicitly bound for the settings to be honored.

7. Select the Enable RNAT TCP Proxy option.

HTTP Parameters

To configure the HTTP parameters of an appliance, complete the following procedure:

1. Expand the System node of the Navigation pane on the appliance.

2. Select the Settings node.

3. Click the Change HTTP parameters link on the Settings page.

4. Select the Version 1 option.
   Note: Select the Version 0 option only if the environment has earlier releases of web browser that do not support Cookie Version 1.

5. Select the Drop invalid HTTP requests option.
   Ensure that you always select this option. It helps in detecting the invalid HTTP headers.
   NOTE: This can cause some resources not to load through a Vserver, so be sure to thoroughly test after enabling. If you have subsequent issues accessing resources, disable this setting and test.

SNMP Alarms

To configure the recommended settings for Simple Network Management Protocol (SNMP) Alarms on an appliance, complete the following procedure:

1. Expand the System node of the Navigation pane on the appliance.

2. Expand the SNMP node.

3. Select the Alarms node.

4. Select the CPU-USAGE alarm in the SNMP Alarms page.

5. Configure the following options in the Configure SNMP Alarm dialog box:

   • Type 95 in the Alarm Threshold field.

   • Type 35 in the Normal Threshold field.

   • Select Informational from the Severity list.

   • Select the Enable option.

6. Click OK.

7. Select the MEMORY alarm and click Open.

8. Configure the following options in the Configure SNMP Alarm dialog box:

   • Type 95 in the Alarm Threshold field.
     Note: If this threshold is reached, then force failover the appliance. If it happens again, then contact Citrix Technical Support.

   • Type 35 in the Normal Threshold field.

   • Select Critical from the Severity list.

   • Select Enabled from the Logging list.

   • Select the Enable option.

Network Interfaces

To configure the network interfaces on an appliance, complete the following procedure:

1. Expand the Network node of the Navigation pane on the appliance.

2. Select the Interfaces node.

3. Select the interface not in use and click Disable.
   Repeat this step for each interface that is not in use.

4. Disable High Availability Monitoring on all disabled interfaces and on the enabled interface that does not require High Availability Monitoring. To disable High Availability Monitoring on an interface, complete the following procedure:

   1. Select the interface.

   2. Select the OFF option for HA Monitoring.

   3. Click OK.

General Best Practices

• For best practices for generic implementation of a Netscaler ADC appliance, please refer to Tech Paper
• For VLAN and core networking, please refer to NetScaler Networking and VLAN Best Practices