Help / Troubleshooting
Q: How do I fix an upgrade failure when the error message is "ipkg_download:
ERROR: Command failed with return value 1: `wget ... '"?
A: This failure is typically caused by a network connectivity issue. First, check the ePower's network settings and verify that the IP address, subnet mask, gateway, and DNS servers are properly listed. Second, check the ePower's proxy settings and verify that they are correct for your network. Finally, on a computer in the same subnet as the ePower, attempt to visit the URL mentioned in the error message. For further help, please contact Cyber Switching's Technical Support.
Q: How do I install the EMC on Windows 7 or Windows Server 2008?
A: Please follow the manual install directions in the EMC Install Guide
, starting on page 7 “Installing the Database”, in order to install the EMC on these particular operating systems.
Q: I see a “TX underrun, resetting buffers” message occasionally in the ePower's data logs. Is this an issue?
A: This is a common "house cleaning" message sent by the kernel when the network transmit buffers are flushed. It can be safely ignored and is a common Linux notification for embedded systems. This diagnostic output and other, similar messages are enabled to help Cyber Switching's Technical Support in the event of a support question.
Q: On my ePower unit, why does the alert settings icon column appear to "flicker"?
A: The rendering engine in some browsers, notably Internet Explorer, can sometimes inappropriately redraw screen content in the middle of a data update. Once the data update is finished, the engine then redraws the screen again, causing the "flicker" phenomenon. This behavior is harmless and can be ignored. If desired, try a different browser, such as Mozilla Firefox, for a more seamless experience.
Q: What happens if I change an outlet’s state when the outlet is in the process of Rebooting?
A: If you turn an outlet On or Off when that outlet is still in the Reboot process, the Reboot is canceled, and the outlet immediately changes to the desired state.
Q: What happens if I change the Off-to-On delay time when an outlet is in the process
of Rebooting?
A: Each Reboot process uses the settings that were applied at the time the Reboot was started. Any changes made after the Reboot starts are used for subsequent Reboot requests.
Q: What is the ePower Reboot sequence?
A: When you Reboot an outlet, the outlet immediately turns Off, then comes back on after the Off-to-On timer expires. The default Off-to-On delay time is five seconds. The delay time can be changed in the Outlet Properties dialog box, in the Web interface.
Q: Why is there no power at the ePower outlets?
A: Check to ensure that the input power cord is plugged in, that all branch circuits breakers on the unit (if any) are closed, and that the outlet is turned On.
Q: On the ePower unit, the message jffs2_sum_write_data: Not enough space for summary, padsize = XXXX. appeared in the system log.
A: The Journaling Flash File System v2 (JFFS2) file system used on the ePower is a highly reliable, fault-tolerant, self-correcting file system designed for performance on embedded systems.
This message indicates a common warning that JFFS2 is using a new segment of Not-And (NAND) gate flash and must first initialize that segment.
You can ignore this message, because it is used only for internal kernel-level debugging.
Q: Where can I find general system information about my Dualcom?
A: System settings can be obtained under the Setup page on the web interface or the System Settings selection on the telnet/serial interfaces. Additional information about your system, including the unit's MAC address, serial number, and firmware revision, may be obtained through a special page available on the web interface.
To access this special system information page, first login to the Dualcom's web interface in your browser as the system administrator account. Next, append the page happiekats.shtml to the URL (i.e. http://192.168.1.2/happiekats.shtml where 192.168.1.2 is your unit's IP address) and hit Enter. The resulting page will contain the MAC address, serial number, and firmware revision along with other diagnostic information that may be helpful if you need support.
Q: Why is there no power at the outlets?
A: Check to ensure that the input power cord is plugged in and that the outlet indicator lights are on.
Q: Why do my arrow keys not function in Windows 2000 when I run Hyper Terminal?
A: Prior to connecting the Dualcom directly to the serial port, download the latest updates and fixes for Win2000, WinXP and WinNT at http://www.microsoft.com
Q: Why does the Dualcom indicate no load when I have my mini hub plugged into one of the outlets?
A: To avoid improper current readings the Dualcom is designed so that any load lower then 0.1A is considered zero.
Q: I can not connect to the Dualcom using the serial port.
A: Check settings to ensure that you are connected to the proper COM port and that the settings on the COM port are 19200, 8, none and flow control set to none
Q: The Dualcom does not appear to be responding to any commands on all the interfaces
A: If for some reason the Dualcom stops responding a soft reset can be performed by quickly pressing and releasing the reset button located on the right side panel of the Dualcom indicated by the nut shaped hole.
Q: Is there a way to reset the Dualcom to default?
A: To reset the Dualcom press and hold the reset button for thirty seconds then release. The reset button is located on the right side of the Dualcom indicated by a metal finished, screw nut shaped hole. PLEASE NOTE: Returning the unit back to factory default will erase all your settings.
Q: When I try to access the Serial or Telnet menu on a Dualcom, the Backspace key seems to not work.
A: The Backspace key is sometimes mapped to different ASCII character codes
depending on the operating system. If you are experiencing this problem, please try using
Ctrl-H instead.
Q: Why does my new Dualcom not respond on the network after I configured it with the same IP address information as the unit it is replacing?
A: Chances are that this is a problem with the network's ARP cache. To optimize the sending of information as quickly as possible, a network device like a switch or router builds an internal list of MAC addresses and their corresponding IP addresses. When you configure your new Dualcom to use an IP address that is already in this list, the router or switch is still using the MAC address for the Dualcom that is being replaced. (For a full explanation of ARP and how it works, visit the Address Resolution Protocol entry on Wikipedia.)
You can test if this is the issue by connecting a laptop directly to the
same switch and VLAN as the Dualcom. If you configure a static IP address
inside the same subnet as the Dualcom's address and are able to get to the
Dualcom's network interface, this is most likely the problem.
There are two solutions to this problem: wait until the network device "forgets" the MAC/IP relationship (usually between 20 and 30 minutes) or force your network device to clear its ARP cache. For further help with either of these, please contact your network administrator or systems vendor as the details are highly specific to your network.
Q: An ePower outlet is not working, and no alert was issued.
A: First, ensure that the equipment connected to the outlet is fully plugged in, and that the equipment is turned On. Next, try turning On the outlet from the ePower Web interface, even if the outlet reports that it is already On. If this does not resolve the problem, contact Cyber Switching’s Technical Support
at support@cyberswitching.com.
Q: How do I connect to the ePower using the RS-232 serial port?
A: Connect an RS-232D serial cable to the ePower’s RS-232 serial port; Set up a terminal emulation program (such as HyperTerminal, Tera Term, or minicom), and configure the program with the following settings:
115200 bps, 8 data bits, no parity, 1 stop bit and no flow control.
Q: How do I reset the ePower to factory default settings?
A: To reset the ePower to factory defaults:
1. Connect an RS-232D serial cable to the ePower’s RS-232 serial port, and open a terminal emulation program, as described in the "Initially Configuring the RS-232 Serial Port to Use the CLI" section in Chapter 2, “Installing the ePower PDU” of the ePower User Manual.
2. Using a firm, thin object (such as the end of an unfolded paper clip), press and hold the reset button for 1 to 2 seconds.
3. When the bootloader appears, press any key to interrupt the bootloader. If successful,
the U-boot>prompt will appear.
If this prompt does not appear, repeat steps 2 and 3.
4. At the U-boot> prompt, enter cfg_rst, then press Enter.
The unit starts booting as normal. During boot-up, the system re-creates the appropriate databases and files.
CAUTION This process cannot be canceled after it starts. All the ePower unit settings will be lost and reverted back to the factory defaults,
including outlet properties and user accounts. Perform this operation
only if absolutely necessary.
NOTE Due to recreating the various databases, the system may take a few extra minutes to boot.
Q: On the ePower unit, the message Erase at XXXX failed immediately, followed by JFFS2: marking eraseblock at XXXX as bad. appeared in the system log.
A: This message indicates that JFFS2 has detected a bad NAND block and corrected the problem. NAND flash commonly wears down over time. The ePower implements “wear leveling,” which significantly reduces the chances of this occurring.
However, if it does occur, the ePower automatically marks the block as bad (as indicated by the aforementioned error message), and re-maps
that bad address to a good address. This not a major problem, and can safely be ignored if you only see a handful of error messages similar to this in the logs. However, if you begin to notice a large number of error messages (greater than 50),
contact Cyber Switching’s Technical Support at support@cyberswitching.com.
Scripting / Automated Control
Q: How can I script control of my Dualcom series PDU?
A: The Simple Network Management Protocol (SNMP) is best suited to remotely control and monitor a Dualcom through custom scripts. While the exact implementation of SNMP in your script will depend heavily on the programming language you choose to use, there are several common threads that any SNMP scripting solution has.
First, ensure that the Dualcom is connected to the network and can be
reached over Telnet or HTTP.
Second, enable SNMP on the Dualcom. On the HTTP interface, the settings can be found under the Setup tab in a section marked SNMP. The settings you choose will be specific for your network and needs. As a best practice, you should choose two SNMP community strings -- one for reading and one for writing. (The SNMP write community string can be used for reading as well, but for the best security you should have two separate strings and only give out the one for writing when absolutely necessary.) By default, the string public is used for reading and the string private is used for writing.
We highly recommend that you test SNMP access to the Dualcom at this point. There are several free utilities that can be used, including Cyber Switching's CSTools utility available on our Support page. For users who want to perform raw SNMP testing, we recommend the Net-SNMP suite of programs due to its free nature and excellent cross-platform support; you will need to download Cyber Switching's SNMP Management Information Base (MIB) from our Support page to properly interpret the SNMP values sent back.
Once SNMP traffic can be sent and received from the Dualcom, you are now ready to begin scripting. There are two common methodologies used when scripting a Dualcom:
- External dependency on CSTools
- Raw SNMP handling in the language itself
CSTools supports batch-mode operation using command line arguments that lends itself quite well to simple scripting. Since CSTools creates a Dualcom-specific facade between the user and SNMP, it is extremely easy to integrate into scripts. However, it does create an external dependency for the script and requires that the script be distributed with a copy of the CSTools executable.
To remove the external dependency on CSTools, the script must therefore provide the needed SNMP functionality itself. Many programming languages have libraries that abstract the raw SNMP calls needed, so please try to use those where possible. For a brief (but incomplete) list of libraries available, see below:
Handling raw SNMP calls inside your script will require an intermediate
familiarity with SNMP and the Cyber Switching MIB (see the download link
above). To truly remove all external dependencies, make sure you either use
the numeric SNMP Object ID (OID) format (1.3.6.1.4.1...) or copy the needed
contents from the MIB file into your script.
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