Abstract

The discard service is enabled by default and used to test connection with the RTU without having another service enabled. To test whether discard is enabled use a terminal software like putty and make a telnet connection on port 9. If disabled the connection will be refused, if successful the connection will be successful. To disable discard service load the attached /etc/inetd.conf, then reboot. To re-enable, reload firmware.

Products

ST-IPm-8460

VT-mIPm-248-D

VT-mIPm-138-D

Use Case: Disable Discard Service

Required Software

Sixnet I/O Tool Kit 5.0.101 or later

Industrial Controller firmware 4.9.152 or later

Test Discard Service

Connection with terminal when enabled.

1. Open Putty or some other terminal software. Try to make a telnet connection with port 9.
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2. Open the connection. If the connection is successful then text can be entered. Nothing will happen because all characters will be discarded.
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No Connection when Discard Service is Disabled

1. Open Putty or some other terminal software. Try to make a telnet connection with port 9.
   • Same as step 1 above. 
2. Open the connection. If the connection is unsuccessful then a message that the connection is refused will pop-up or the window will close immediately.
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Load /etc/inetd.conf with the discard service disabled

By default the discard service enabled. The attached inetd.conf has commented out the discard service, so it never starts up. The persistent even after reboots. To reset, go to Operations>Advanced Operations>Upgrade Firmware to reload firmware.   

1. In the Tool Kit go to Configure>Configure Station/Module>Files to Load Tab
2. Add the inetd.conf file from this technical note. It has the lines to comment out discard services. Select “Copy files to the station.” “Load as (destination)” must be /etc/inetd.conf
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3. Click on each file in the files to load tab. Change the permissions to -rw-r--r-- or octal 644.
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4. To load the file to the station go to Operations>Load>Load Advanced. Select only the user files. Clock the load button. After the load is complete cycle power to the Industrial Controller.