APC PDU configuration trick

I was trying to configure an APC7811 PDU, which has a network port for remote access. It’s a metered PDU so you can log in remotely and look at power consumption.

I’d never had to configure one before so I just popped in the CD that came with it and tried to configure an IP address by using the discovery tool. Regardless of which IP address I tried, I kept getting “The IP is already in use on the network.”

This configuration method is in the documentation, but it’s buried at the end… I think I’ll use this every time now as it’s fast and doesn’t require the vendor’s CD.

The MAC address is on the back of the PDU and on the Quality Assurance slip included in the package.

  1. Use ARP to define an IP address for the PDU,
    and use the PDU’s MAC address in the ARP
    command. For example, to define an IP
    address of 156.205.14.141 for the PDU that has
    a MAC address of 00 c0 b7 63 9f 67, use one
    of the following commands: Windows command format:
    arp -s 156.205.14.141 00-c0-b7-63-9f-67 LINUX command format:
    arp -s 156.205.14.141 00:c0:b7:63:9f:67
  2. Use Ping with a size of 113 bytes to assign the
    IP address defined by the ARP command. For
    example: Windows command format:
    ping 156.205.14.141 -l 113 LINUX command format:
    ping 156.205.14.141 -s 113
  3. Use Telnet to access the PDU at its newly
    assigned IP address. For example: telnet 156.205.14.141
  4. Use apc for both user name and password.

At this point the IP address is configured for the interface, you can browse to the IP via HTTP. Don’t forget to delete your static ARP entry.

25 comments

L

I had a ‘cool’ moment when it worked for me like this :- – the APC PDU was a decommisioned-repurposed one – it had a static IP configured, so it wasn’t even sending a DHCP request
– but i had a Mikrotik router about – i connected (probably, it should be to an interface with an IPv4 address and subnet attached) the PDU to it
– then I used the Tool -> IP Scan feature, on the interface, WITHOUT entering the destination network to scan, JUST the interface
– this MIGHT take a while – but it eventually had detected THE static IP with matching MAC address
– I configured a /24 subnet, such that it would contain THE static IP of the PDU and attached it to the same interface as secondary IP address
– and used ssh (telnet was disabled) to log in to the PDU, from the Mikrotik (Tools -> Telnet, choose SSH and enter the apparently not-changed-by-previous-user username ‘apc’, and it logged in)
– using the ssh from Mikrotik i have been able to change settings of the PDU (but trying to use e.g. PuTTY, it wasn’t happy to work with, could be possible maybe to use PuTTY but this was likely due to the PDU ssh implementation being old)
– the PDU is now working for me as I inteded 🙂

Mutlu Basdas

wow commenting to this post on 2021!! :)) I have purchased an used APC AP8941 and can not figure out how to set an IP. Do I need to be connected with the serial cable? I tried with only ethernet cable both connected to the same router, laptop also hardwired obviously. I’m not really an IT person so I don’t think I really know what I’m doing to begin with.
But I tried the arp command and it didn’t work. Also the PDU is showing a IPv4 address already when I scroll through PDUs menu. How can I connect to the PDU, let me know please. Thanks!