TCPPort Monitor

The TCPPort monitor provides coverage for services that are not tested by the other monitors. It detects and responds to commands or strings on a TCP port. This monitor is particularly useful for monitoring bespoke services.

Guidelines for configuring the TCPPort monitor

The TCPPort monitor tests TCP-based services by connecting to the service, monitoring messages, received from the service and sending responses to it.

To configure a test, you define a sequence of expected messages and responses that comprise a normal interaction on that service.

For example, a standard interaction for a telnet service involves the following sequence:

• The telnet service sends a login message, prompting for a username.
• The client sends a response that contains a username.
• The telnet service sends a message that prompts a password.
• The client sends a response that contains a password.
• If the login attempt is successful, the telnet service sends some form of greeting message.

The monitor's WaitForn and Sendn properties, which are specified define the expected messages and the responses to those messages. These properties in the monitor properties file, define how the monitor interacts with the TCP service:

• WaitForn properties are regular expressions. The monitor uses them to match messages that are received on the monitored port.
• Sendn properties are literal strings that the monitor writes to the port.

Note: If required, you can insert control characters into these properties by using a text editor that supports control character insertion.

The format for defining WaitForn and Sendn properties is:

WaitFor1: 1st received message
Send1: 1st response
WaitFor2: 2nd received message
Send2: 2nd response
...
WaitFor5: 5th received message
Send5: 5th response

When the monitor reaches the first unset WaitFor property, it stops sending and receiving. If the MonitorDisconnect property is set to 0, the monitored service must close the connection that is opened by the monitor otherwise the monitor reports the message Timed out waiting to read in its $message element. With many services, connection can be closed by sending a quit command. If MonitorDisconnect is set to 1, the monitor disconnects after the last Send or WaitFor command completes, or the timeout is reached, whichever occurs first.

Configuring the TCPPort monitor service test

Use the TCPPort monitor configuration parameters to define service tests.

Table 2. TCPPort configuration

Field	Description
server	The IP address of the system on which the target service is running. Example is server.mycompany.com
port	The port on which to connect to the target service.
description	A text field for providing descriptive information on the element.
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 failure is indicated. Default: 0
retestinterval	The time, in seconds, to wait between each failure retest. Default: 10

Note: Monitor the availability of the telnet service that runs on the host server.mycompany.com on port 23. Use the credentials user or guest to log in to the server and close the connection immediately after login. Run the test at 5-minute intervals, and set a 10-second timeout on connection attempts.

1.Add the following entries to the TCPPort properties file:

WaitFor1: ".*[Ll]ogin:"
Send1: "user"
WaitFor2: ".*[Pp]assword:"
Send2: "guest"
WaitFor3: ".*%"
Send3: "exit"

2.Start or Restart the TCPPort monitor.

Regular expression matches

Perform a regular expression search on the information that is downloaded by entering up to 50 different regular expressions. The TCPPort monitor attempts to match the contents that are 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.

For more information, see Table 3.

Monitor elements

The following table describes the additional elements for the TCPPort monitor.

Elements indicated by an asterisk (*) are available as attributes. The names of the attributes are shown within brackets. Absence of an asterisk indicates there’s no equivalent attribute. Attributes that are shown in bracket but without an element indicates that they are only available as attributes, there’s no equivalent element.

In addition to the test results common to all elements, the TCPPort monitor generates a set of test results that contain data specific to TCPPort service tests.

Table 3. TCPPort monitor elements 

Element	Description
$bytesPerSec	The average number of bytes transferred each second.
$bytesTransferred	The number of bytes uploaded or downloaded.
$connectTime*(ConnectTime)	The time taken to establish a connection with the target server.
$downloadTime*(DownloadTime)	The time taken to download data.
$lastlineThere’s	The contents of the last line received from the target server.
$lookupTime*(LookupTime)	The time taken to obtain the IP address of the host server.
$networkError	Contains any network errors during the connection.
$port* (Port)	The port on the target server the monitor tried to connect to.
$waitingFor	If the connection terminates before the monitor completes its sequence of waits and sends, this element contains the contents of the last WaitFor property.