So what’s happening on the Pi front

Some ssh strangeness enters the scene

We had a NBN (National Broadband Network) outage here caused by a broken cable in the copper between the neighbourhood node and our place. NBN Co got onto it pretty quickly and it was repaired within the day.

When the tech. arrived the first thing he told me was that our modem/router was no longer supported and that we needed to use the newer one that I had. The reason that we were using the old the old modem/router is that the newer model couldn’t do port forwarding or dynamic DNS. It transpired that the new model had had a firmware update and both dynamic DNS and port forwarding were now supported. This was proven to be the case and the configuration was entered into the new modem/router.

Enter the SSH problem. My two Pi4’s were connected via a hub and ethernet cable, my Pi-Zero was connected via 2.4GHz wifi and my Pi-400 is connected via 5GHz wi-fi. With the new modem I can’t SSH across connection modes. For example, I can’t SSH into any other system on 5GHz from a system on 2.4GHz or ethernet. I can, however, connect to any other system on 5GHz wi-fi. I spent days playing with this until I found a technical document which described the problem as I was seeing it. It only applies to SSH so I just use telnet now. Strangely, I can SSH into any system via where xxxx is the port that’s forwarded to the desired systems port 22.

An advantage of the new modem/router is that if the NBN decides not to play nice is uses the 4G network as a backup. In the backup mode there is a huge disadvantage though. Dynamic DNS doesn’t work and neither does port forwarding.  Oh well, I can live with that as the NBN goes down very rarely.

Some PoE+ hats

Up behind the TV I had a rats nest of cables and power strips. The design of the Raspberry Pi power supply with its “wings” means that I need a few power strips rather than just one. As well as three Pi’s we have the TV and phone and laptop chargers so if I could get rid of the Pi power supplies I’d only need one power strip. I was already using an eight port PoE (Power over Ethernet) hub so all I needed was a few PoE hats which were duly ordered as were a few plastic / acrylic PoE compatible cases.

In my usual style I went for it, putting the Pi’s and the PoE hats in the new cases. Looks OK too. here’s a link to the PoE HAT and here’s the link for the PoE HAT compatible case.Straight off the bat it all worked perfectly apart from the fan going at full speed and being annoyingly loud. Clearly something needed to be done about that. Anyway I installed the PoE HATs’ and cases on the other two Pi’s  – a Pi3B+ and the other Pi4B 1GB so I now have to Pi4’s (1GB and 4GB) and a Pi3B+ with PoE working perfectly.

Next came the taming of the fans. I very nearly found the end of the internet finding what I needed. It transpired that a few lines in /boot/config.txt would do the trick.


I assume that there are four fan speeds zero, quarter, half and full speed. I gleaned this by watching the output from “cat /sys/devices/platform/rpi-poe-fan@0/hwmon/hwmon1/pwm1”. This is the PWM value which seems to be either 0, 64, 128 or 255. I don’t know if there is any more granularity than that though.

In /boot/overlays/README there is a concise explanation of what dtparam=poe_fan_tempn lines do.

OK so that’s three Pi’s powered by PoE hats. The fans are under control and quiet and seem to run at the PWM of 64 or 128 levels with a temp of 55 to 65 degrees C which is OK as the CPU doesn’t get throttled back until it reaches 85 degrees C. Having the three Pi’s powered by PoE enabled me to put two of them in the cabinet under the TV out of sight. Bonus.


A Pi3B+ enters the fray

While the PoE stuff coupled with the SSH stuff was going on I thought that I’d reorganise what was where.

The Pi-400 remains as my desktop system although that’s in the process of being upgraded from Buster (Debian 10) to Bullseye (Debian 11) and so far the 64bit Beta is working quite well apart from a couple of known issues concerning Bluetooth and wi-fi.

My 1GB Pi4 is now purely a NAS server with about 10GB of attached storage on spinning rust. It is running Bullseye 64bit headless with no desktop installed. Apart from PiOS Lite I have only installed telnetd, telnet, ftpd, ftp, Samba and NFS server.

My Pi4 4GB is now a media centre and database server. The database is for this web server and is MariaDB. It’s used to play music, TV shows, etc with VLC. The media files are all on the NAS server Pi. It’s still running on Buster with 64bit Kernel and 32bit userland though. I’m waiting for Bullseye 64bit to come out of Beta before I upgrade it.

The Pi3B+ is now the web server as well as a TVHeadend server. It’s also headless with only ftp, ftpd,telnet, telnetd and TVHeadend installed over PiOS Bullseye Lite. I can access TVHeadend remotely so that we can watch TV when we’re travelling in places where we have a 4G connection available on our phones and tablets but where there is no terrestrial TV reception. Our portable TV plays nicely with my iPad Mini 5 and it works very well indeed. Sometimes, when we have full coverage we can even watch HD TV although standard definition is plenty good enough.

The Pi-Zero is now my GPS disciplined time server with a Real Time Clock and that’s its only function. It runs on 32bit Bullseye headless.

So what’s next ?

I think the next step is to try to move my wife to a Pi. She’s seen how well the Pi-400 works as a desktop so now all I have to do is to wean her off Windows. I had in mind upgrading my Pi-400 to a Pi 4 8GB as I do a fair bit of memory hungry photo and video processing. The Pi-400 will suit my wife perfectly as she does proof reading and word processing and gets most of her work via e-mail. The only issue I can see is not having Outlook but I’ve found that Evolution is a workable substitute for Outlook. She also does a load of web based work using Firefox so PiOS with Firefox installed will work perfectly for her. The Libre Office Suite works perfectly with Microsoft format documents so there’ll be no compatibility issue there either.

As far as the rest goes I’m still not entirely happy with where I’ve got everything so I’ll need to think about that. I also need to streamline my storage. I have a lot of spinning rust hard drives so re-organising them is also a priority – some partitions are short on free space while others have heaps. Loads are very uneven so evening things out would be good.

For the server(s) and desktops I really, really want to get rid of wi-fi and for wired systems move to ethernet over power line. I don’t like wi-fi, never have. Wi-fi is useful for portable devices like tablets, iPads, phones, etc. but in my view has no place with non portable devices.

So they’re my plans, anyway. Will it all happen ? Dunno…. We’ll see.



Leave a Reply

Your email address will not be published. Required fields are marked *