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The following section describes some interesting examples of the SLCheck utility. SLCheck can be used in local area networks and on the Internet, only the TCP/IP protocol is necessary. Please ensure that your firewall allows the connection.

Monitor a HTTP server while directly connected to the internet (without proxy server):

SLCheck -p 80 -a -u / -r "HTTP/1.1 200 OK"

Port 80 of server (without any subdirectory) is requested. "HTTP/1.1 200 OK" is the expected answer. If the server answers within 2 seconds (default) with the expected answer, batch file c:\SLCheck\CheckOK.cmd will be executed. If it doesn’t answer within 2 seconds, c:\SLCheck\CheckTimeout.cmd will be run. c:\SLCheck\CheckMismatch.cmd will be executed if the server answers with another string. Option -u has "/" as the default value, so it would not have been necessary to specify it in this example.

You can also use this command to monitor your intranet server.

Monitor an internet HTTP server from your LAN (via proxy server)

SLCheck -p 80 -a -u -r "HTTP/1.0 200 OK"

IP address is the address of your proxy server. That’s the address of the server you have to configure in your browser. The proxy server will be requested for the URL If it answers within the timeout of 2 seconds with „HTTP/1.0 200 OK“ then the file CheckOK.cmd will be launched, otherwise the file CheckMismatch.cmd or CheckTimeout.cmd.

Monitoring an internet HTTP server from your LAN (via proxy server), second example:

SLCheck -p 80 -a -u -r "HTTP/1.1 200 OK"

Server answers to the request „SLCheck -p 80 -a -u /“ with „HTTP/1.1 404 Not Found“. In this case you can use option -u to declare a special file to be loaded, in this example „“. You could also request a .gif file instead of a .htm file.

Monitoring your internet connection (via proxy server). 2 URLs will be monitored:

SLCheck -p 80 -a -u -r "HTTP/1.0 200 OK" -a2 -u2 -r2 "HTTP/1.0 200 OK"

The two URLs and are requested at proxy server Each request expects „HTTP/1.0 200 OK“ to return. If both requests fail (wrong return string or timeout), batch file CheckFatal.cmd will be executed additional to CheckMismatch.cmd or CheckTimeout.cmd.

Monitoring an internet SMTP server:

SLCheck -p 25 -a -r "220"

A SMTP connection (Port 25) to server will be established. If the "220" will be returned, batch file CheckOK.cmd is executed, otherwise CheckMismatch.cmd or CheckTimeout.cmd.

Monitoring an Exchange server on the local area network. A connection with the internet mail service will be established.

SLCheck -p 25 -a -r "220" -w 500

IP address is the address of the Exchange-Server. The timeout was set to 500 milliseconds (default: 2000ms)

Monitoring a FTP server:

SLCheck -p 21 -a -r "220 NcFTPd Server (licensed copy) ready." -w 5000

A connection on port 21 (FTP) is established with server The expected return string is "220 NcFTPd Server (licensed copy) ready.". If the server does not answer correctly within 5 seconds, one of the batch files CheckMismatch.cmd and CheckTimeout.cmd will be executed.

Monitoring a Telnet server:

SLCheck -p 23 -a -r "˙ý"

The address of the Telnet server ist You can find detailed information in section Answer Strings.

Monitoring a POP3 server:

SLCheck -p 110 -a -r "+OK T-Online POP3 Server fpopd ready." -nookbatch

A connection with server is established on port 110 (POP3). If the server returns "+OK T-Online POP3 Server fpopd ready.", nothing will be done because of the option -nookbatch. If the server does not answer within the default timeout (2 seconds), batch file CheckTimeout.cmd will be launched. If the server returns a different text, CheckMismatch.cmd will be executed.

Monitor a Citrix server (do not run in DOS box!):

SLCheck -p 1494 -a citrix01 -r "ICA" 

This command sends a request to the ICA (Independent Computing Architecture) port of a Citrix Metaframe server (Presentation server) named citrix01. ICA protocol is the most important protocol in Citrix environments. You can't execute this command in a DOS box because the special characters before ICA produce backspaces. You can copy & paste the command from this website and put it in a batch file or place it directly in the scheduled tasks command line - first of all, create a scheduled task with SLCheck.exe in the command line and then modify the task.

Monitoring an IMAP4 server:

SLCheck -p 143 -a

An IMAP4 connection with server is established. Option -r was not used, so SLCheck shows a popup window with the answer string.

To use SLCheck for monitoring please use

SLCheck -p 143 -a -r "* OK"



How does SLCheck

Service Level

Monitor your Internet

HTTP Monitoring

FTP Monitoring

SMTP Monitoring

POP3 Monitoring

Citrix Server Monitoring

Answer strings

Command line Syntax

Batch files parameters