Resetting APC AP7920 PDU

I have three APC PDUs – all the AP7920 model, they monitor power consumption and allow remote switching of a bunch of devices in the main rack. Last week I sourced a fourth device to live in the garage comms rack. This came from eBay, and as has been the case with every used device I’d have, it still had old IP config and an unknown username and password set.

So for future-Howard’s benefit: how to reset the password and settings so it can be set up from scratch…

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Conditional DNS on UniFi’s UDM-Pro

A quick How To for getting conditional DNS forwarding working on the UDM-PRO hardware. Before this upgrade I ran a CloudKey Gen 2 controller and a USG-PRO-4 for routing – this allowed me to deploy custom configuration via the config.gateway.json to insert extra options to the running config.

The options I needed were to force the DNS server on the gateway to check against my Active Directory DNS for those entries that arrive with the correct suffix – ad.durdle.com. This allows the lookup of clients from the UniFi’s DHCP lease table as well as AD DNS entries.

The UDM-PRO is a completely different beast from the old controller and gateway, running an entirely different OS. It doesn’t support config via json. So what’s a geek to do?

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Windows 10, why you no sleep?

A (minor) annoyance of my recent new build Windows 10 machine has been its inability to properly sleep. I’d hit Sleep, it’d go through the motions of spinning down fans and sleeping… and then immediately spring back into life.

I’ve actually put up with this for months, but yesterday spent some time working out what was happening, so for Future Howard’s benefit, here’s how to see what is keeping your machine awake.

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“Alexa, where are the cats?”

As is well documented, I have a significant number of feline overlords who thanks to multiple Sure Petcare cat flaps can come and go as they please. The new Connected range of cat flaps comes with a web site, iOS app (a thin skin over the same web site) and is built using what appears to be a pretty solid RESTful API. A few months ago I spent a bit of time monitoring the web app to reverse engineer bits of the API, and then built an Alexa skill so that I could ask my house where all the cats are.

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UniFi, VLANs, Sonos and igmp-proxy

As an exercise in good network health, I spent some time last month moving all the “Internet of Things” devices in my network onto their own segregated VLAN. I’ve configured things so that by default no traffic can leave the IoT network without my adding explicit rules to permit it. This protects the trusted side of my network from potentially dodgy traffic from the IoT devices with cheap WiFi chips and Chinese hosted servers. (I’m looking at you ThermoGroup.)

Logically, my network ends up looking something like this, with separate networks for the trusted kit, the IoT devices and the guest wireless network.

One wrinkle with this approach is that – by design – each VLAN is its own broadcast domain. That means the devices on my primary trusted VLAN can no longer use multicast to discover devices on the IoT VLAN. The most obvious victim of this was Sonos – none of the controllers could see the Sonos devices once I separated the LANs.  Enter igmpproxy running on my router – the UniFi USG-PRO-4.

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