Product Documentation

Configure URL passive persistence

With URL Passive persistence, when the Citrix ADC appliance receives a request from a client, it extracts the server IP address-port information (expressed as a single hexadecimal number) from the client request.

URL passive persistence requires configuring an advanced expression that specifies the query element that contains the server IP address-port information. For more information about classic and advanced policy expressions, see Policies and Expressions.

The following expression configures the appliance to examine requests for URL queries that contain the string “urlp=”, extract the server IP address-port information, convert it from a hexadecimal string to an IP and port number, and forward the request to the service configured with this IP address and port number.

HTTP.REQ.URL.AFTER_STR(“urlp=”)

If URL passive persistence is enabled and the above expression is configured, a request with the following URL and server IP address-port string is directed to 10.102.29.10:80.

http://www.example.com/index.asp?&urlp=0A661D0A0050

The persistence time-out value does not affect this persistence type; persistence is maintained as long as the server IP address-port information can be extracted from client requests. This persistence type does not consume any appliance resources, so it can accommodate an unlimited number of persistent clients.

To configure URL passive persistence, you first configure persistence as described in Configuring Persistence Types That Do Not Require a Rule. You set the persistence type to URLPASSIVE. You then perform the procedures provided below.

To configure URL passive persistence by using the CLI

At the command prompt, type:

set lb vserver <vserverName>  [-persistenceType <persistenceType>]  [-rule <expression>]

Example:

set lb vserver LB-VServer-1 -persistenceType URLPASSIVE –rule HTTP.REQ.URL.AFTER_STR(“urlp=”)

To configure persistence on a virtual server by using the GUI

  1. Navigate to Traffic Management > Load Balancing > Virtual Servers, and open the virtual server.
  2. In the Persistence section, choose the persistence type that meets your requirement. The most suitable persistence type for the virtual server is available as option buttons. Other persistence types that are applicable to the specific virtual server type can be selected from the Others list.

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Note

Prior to NetScaler release 12.0 build 56.20, all persistence types are available in a single Persistence drop-down list without any option buttons.

Configure URL passive persistence