Netgear Powerline won't pair: how to troubleshoot?

Question

A while back, I bought a pair of Netgear Powerline devices (PLP2000's) as an alternative to a sketchy wifi connection. They work perfectly.

I wanted to provide wire-based network connectivity to another part of the house and bought another pair. Unfortunately, I can't get either of the new adapters to pair with the existing adapters.

I believe that the pairs of adapters are given identical network encryption keys at the factory and the device I'm trying to add doesn't match. I called support, and they told me that I need to connect two adapters to my router - and effectively have two powerline networks. I think that's incorrect, based on this video, which suggests I can add have a total of 16 adapters acting as a single network: https://youtu.be/GKy90rPLo6k?t=66 This post also suggest that it's possible to simply add a third adapter: Powerline Networking - can I just add another adapter

I notice that other powerline adapter vendors, e.g. TP-Link, have a utility app that allows the user to edit properties such as the security key. This particular model from Netgear doesn't have an equivalent utility.

There is a password printed on the label:

This wwould suggest that some sort of client or application could connect to this remotely, given the right connection parameters.

I'm curious to know how this technology works. It seems like this is a different layer of network, below TCP/IP since the powerline adapters don't have an IP address (at least, based on a quick glance at my DHCP tables).

So, does anyone know how I can connect to these devices from a client or language (Java/Python). I'm hoping I can login remotely, match the network encryption keys across all the devices, and everything will magically start working.

Answer 1

Yes, Homeplug AV devices accept configuration commands via Ethernet frames using a special protocol (0x88E1), and optionally relay them to other Homeplug devices through the powerline link.

The base protocol used is part of the Homeplug specification, so you can perform pairing (i.e. changing the "Network Membership Key") using any manufacturer's "PLC utility" software.

• Qualcomm publishes open-plc-utils, a set of command-line tools. (They're the biggest Homeplug AV manufacturer – most consumer HPAV devices just use a Qualcomm chip.)
• I found Netgear's powerline utility, even though it's not listed in your model's support page.
• Even TRENDnet's or TP-Link's powerline utility / PLC utility will work in a pinch. They might not recognize the exact model, or they might not show the graphical network topology right, but the basic control commands remain the same.

Note that a local device will accept configuration commands via Ethernet without any device key. The device key (i.e. the password in your photo) is only used for sending commands via powerline, e.g. PC→Ethernet→adapter1→powerline→adapter2.

Finally, some Homeplug devices do have an IP address for configuring other things, such as WiFi SSID for those acting as an AP/repeater/extender. In that case, their config webpage usually includes a section for Homeplug pairing as well.

(For example, in my WiFi-capable TP-Link HPAV adapter, there is a section in which I can add other adapters' "device keys". Then I can change the network key in this adapter, and that will force-pair all other adapters in the powerline network.)

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Useful open-plc-utils commands (based on a shellscript I made to remember them):

• List devices: int6kstat -r, plctool -r, int6kstat -m, etc.
• Show topology: int6kstat -t
• Convert a password to a network key: hpavkey -eN $passphrase
• Set network key on local Ethernet-connected adapter: plctool -M -K $netkey $targetmac (where $targetmac may simply be local)
• Relay the 'set network key' command to another adapter via powerline: plctool -J $targetmac -D $devicekey -K $netkey $relaymac
• Retrieve a local adapter's "parameter block": plctool -I

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I think all HPAV devices have a physical 'Pair' button. From what I understood, pressing this button either accepts a NMK currently being broadcasted, or starts broadcasting the device's own NMK for two minutes. However, I'm not sure what the correct usage for 3+ devices is:

• Pressing the 'Pair' button first on a paired device, then on a new device, should be enough to accept that device into the existing network.

• Alternatively, pressing the 'Pair' button on one device, then running around to press it on all other devices within 2 minutes, should work to re-pair them fully.

• However, pre-paired devices might have this function disabled. (When management software sets the NMK, it may set a flag to prevent pairing for this NMK.) If that's the case, holding the 'Pair' button for 10+ seconds should reset everything to the default passphrase (which is HomePlugAV).