HTTP Monitor

The HTTP monitor checks the availability and response time of web servers.

It can monitor individual web pages, including that uses CGI, which would normally require the user to enter data into fields. It can also monitor the download time for elements such as images on a web page.

Guidelines for configuring HTTP monitor

The HTTP and HTTPS monitors check the availability and response time of web servers. Use the HTTP monitor in the following situations:

• The target website is static.

  For dynamic websites, use the TRANSX monitor.

• The target website is served over the HTTP protocol.

  For websites that deliver content over the HTTPS protocol, select the HTTPS monitor.

• To perform monitoring across multiple platforms.
• Where speed is a determining factor (the HTTP monitor provides high performance).

HTTP request types

The HTTP monitor emulates a web browser that supports the HTTP/1.0 protocol. To test the web server, the monitor sends it a request for a web page using any of the following HTTP request types:

• HEAD

  The HEAD command attempts to access a web page and return the HTTP header. Issuing the HEAD command is a fast way to check that a web page is accessible.

• GET

  The GET command attempts to access the web page and return the whole page, including the HTTP header. It doesn’t attempt to return files associated with the page, such as images.

• GETALL

  The GETALL command attempts to access the web page and return the whole page including the HTTP header, background, images, applets, frames, cascading stylesheet (CSS) files, and scripts. Like the HEAD and GET commands, this command also checks that a web page is accessible, but because the GETALL command returns the whole page and all its associated files, it may give a more realistic indication of the time taken to access the page. The monitor also uses multiple threads during a GETALL command to more accurately match the behavior of web browsers.

• POST

  The POST command attempts to access a web page that contains an HTTP form and complete the fields of that form. Add body text for the POST request to the Body tab in the Internet Service Monitoring configuration, or use the @Body group in the Internet Service Monitoring configuration or ismbatch. Alternatively, you can use the FORM parameters. You can’t use both Body text and FORM parameters in the POST request.

Using a proxy server

You can test the availability of web pages through a proxy server. When you configure the monitor to use a proxy, it sends HTTP requests through the proxy. If required, you can bypass the proxy cache. You configure the parameters for the proxy server on the Proxy Details tab. The HTTP monitor supports authenticated access to proxy servers. This authentication is independent of any authentication required by the target web page.

Proxy server elements

In earlier versions, when you configured a profile element to use a proxy server, by default the HTTP monitor inserted the name of the proxy server and port into the $server and $port elements, instead of the name and port of the intended destination server. To preserve the value of the intended destination server name and port in earlier versions, set the generateProxyTokens property to 1, or start the monitor with the -generateproxytokens command line parameter.

In addition to preserving the values of the $server and $port elements when this property or command line parameter is set, the monitor generates the $proxyServer, $proxyPort, $proxyAuthType, $proxyUsername, and $proxyCache elements.

Authentication

If the web page that you want to monitor, or the proxy server you want to test, requires authentication specify credentials for accessing the page in the authenticationtype, username, and passwordparameter fields on the Advanced or Proxy Details tab.

To disable authentication, set authenticationtype to NONE.

To select basic authentication:

1. Set the authenticationtype to BASIC.
2. Set username and password to those required by the web page or proxy server.

To select NTLM:

1. Set authenticationtype to NTLMv1 or NTLMv2.
2. Set username and password to those required by the web page or proxy server.

Note:

The monitor limits the length of HTTP requests to 4096 characters. If the length of the additional form data results in a request length that exceeds this limit, the monitor doesn’t include the additional form data in the request.

Configuring HTTP Monitor Service Test

Use the HTTP monitor configuration parameters to define HTTP service tests.

Table 2. HTTP monitor configuration

Field	Description
server	The host name of the server to be monitored. Example is www.mycompany.com
page	The URL of the page to be monitored. Example is index.html
description	A text field for providing descriptive information on the element. Example ismonitoring via a proxy server
port	The port on the HTTP server to use. Default: 80
localip	Specifies the IP address of the network interface that the monitor uses for the test. If this field is empty, the monitor uses the interface specified by the IpAddress property.
version	The HTTP protocol version to be used: 1.0 1.1 Default: 1.0
command	The HTTP request type: HEAD GET GETALL POST Default: GET
formname	When used in a transaction, the HTTP monitor scans the specified form for default values. Any values found are automatically completed the next HTTP step in the transaction.
authenticationtype	Specifies the challenge -response authentication mechanism for authenticating network users: NONE - No authentication BASIC NTLMv1 - Windows NTLM version 1 challenge/response authentication NTLMv2 - Windows NTLM version 2 Default: NONE
username	The username (account name) for the monitor to use to log in to the server.
password	The password corresponding to the username for the monitor to use to log into the server.
timeout	The time, in seconds, to wait for the server to respond. Default: 30
poll	The time, in seconds, between each poll. Default: 300 .
failureretests	The number of times to retest before indicating a failure. Default: 0
retestinterval	The time, in seconds, to wait between each failure retest. Default: 10
verifycertificate	It’s by default disabled.
Proxy details
server	The host name of the proxy server.
port	The port on the proxy server to use. Default: 8080
authenticationtype	The server authentication type for the proxy server. For more information, see previous authenticationtype. Default: NONE
username	Used by the monitor together with the password to log into the proxy server.
password	Used by the monitor together with the username to log into the proxy server and the label is password.
useproxy	Configures the monitor to perform the request using a proxy server. proxy (use true in ismbatch) noproxy (use false in ismbatch) Default: noproxy
hostnamelookuppreference	Determines which IP version, IPv6 or IPv4, is applied to the supplied host name. The options are: default sets the monitor to use monitor-wide properties settings. This is the default. 4Then6 selects IPv4 and then IPv6. Uses IPv4 addresses if they are available. If no IPv4 addresses are found, IPv6 addresses are used. 6Then4 selects IPv6 and then IPv4. Uses IPv6 addresses if they are available. If no IPv6 addresses are found, IPv4 addresses are used. 4Only selects IPv4 only. Uses IPv4 addresses only. If there are no IPv4 addresses, the poll returns an error. 6Only selects IPv6 only. Uses IPv6 addresses only. If there are no IPv6 addresses, the poll returns an error. 6Or4 selects either IPv4 or IPv6. Uses the first address returned from the host name.
nocache	It’s by default set to cache.

Regular Expression

You can perform a regular expression search on the information being downloaded by entering up to 50 different regular expressions. The HTTP monitor attempts to match the contents retrieved to each of the regular expressions. If a match for a specified regular expression is found, the matched lines (or as much as can fit in the monitor’s internal buffer) are returned in the corresponding $regexpMatchn element. If the regular expression matches more than once in the information downloaded, only the first match is returned. The status of each regular expression test is indicated by the $regexpStatusn elements. You can use the regular expression matches and their status information as criteria for service level classifications. SeeTable 3 for information about regular expression syntax,

Head and Form parameter

The HTTP monitor can send extra data in the header fields and message body of HTTP requests.

You configure the parameters for this extra data on the Parameters tab. The parameters are Name, Value and Type and they operate in the following way:

• Name-value pairs of type HEAD specify additional header fields, such as User-Agent and Referer, included in all HTTP requests sent by the monitor. Header fields may be specified for any type of HTTP method (GET, GETALL, HEAD or POST).

  For ITCAM for Transactions V7.4.0.1 and later, the default user agent head parameter, Mozilla/5.0 (ISM-MONITOR) is added for every new HTTP or HTTPS element. The default user-agent header is so that the HTTP and HTTPS monitors can be used for websites that switch content based on the browser client.

• Name-value pairs of type FORM specify extra data included in the message body of HTTP POSTrequests sent by the monitor. If the target page contains a form matching the name specified in the formname field, the monitor treats any name-value pairs in the form as if they were configured in the profile element.

Note:

The monitor limits the length of HTTP requests to 4096 characters. If the length of the additional form data results in a request length that exceeds this limit, the monitor doesn’t include the additional form data in the request.