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March 8 2022 NordVPN, Random forest, stepper motor, web server scripting, recycling

Posted on March 11, 2022
( 7 minute read )

Brian said he had gone back to using a PBX as the interface for cordless ’phones and his mobile. The mobile connects via Bluetooth but the audio quality is poor.

He had discovered that the Raspberry Pi 2 is the minimum on which you can use NordVPN with which he is using the Raspberry Pi as a gateway.

NordVPN Raspberry Pi Gateway Setup
==================================

Created Sunday 05 July 2020
+Install NordVPN App on Debian Linux

To allow packet forwarding
In /etc/sysctl.conf uncomment the line:

net.ipv4.ip_forward=1

Then run this script

sudo iptables -t nat -A POSTROUTING -o nordlynx -j MASQUERADE
sudo iptables -A FORWARD -i eth0 -o nordlynx -j ACCEPT
sudo iptables -A FORWARD -i nordlynx -o eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A INPUT -i lo -j ACCEPT
sudo iptables -A INPUT -i eth0 -p icmp -j ACCEPT
sudo iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT
sudo iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
sudo iptables -P FORWARD DROP
sudo iptables -P INPUT DROP
sudo iptables -L
sudo apt-get install iptables-persistent
sudo systemctl enable netfilter-persistent

│ Current iptables rules can be saved to the configuration file /etc/iptables/rules.v4. These rules will then be loaded automatically during system startup.

│ Rules are only saved automatically during package installation. See the manual page of iptables-save(8) for instructions on keeping the rules file up-to-date.

│ Current iptables rules can be saved to the configuration file /etc/iptables/rules.v6. These rules will then be loaded automatically during system startup.

│ Rules are only saved automatically during package installation. See the manual page of ip6tables-save(8) for instructions on keeping the rules file up-to-date.

│ Save current IPv6 rules?

He had also discovered that his Android box would not work with iPLAYER whereas using an Android browser worked fine.

David said that you should always give IPv6 as well as IPv4 and suggested he add these lines to /etc/sysctl.conf to include IPv6:

net.ipv6.conf.all.forwarding=1
net.ipv6.conf.eth0.accept_ra=2

Darren is now on his final OU project in which he is investigating digitally signing files/folders; where the signature is approximately the same, you can say that the contents are similar. You train the autoencoder, which works like a compression rather than an encryption program, on files to produce a signature in the form of a small array. But how do you compare these signatures? You need to train both the encoder and the decoder at same time. In the end, a very compressed signature is useful for comparisons.

Darren wondered if people could think of any bloopers which might throw light on what to beware of.

He is also using Random forest decision trees to study how neurons decide how to connect themselves.

He also mentioned that he had a problem with errors on a WD rotational hard drive? David wondered if it was a USB cable problem or vibration from a nearby speaker or just a bad hard drive.

David suggested he used smart, noting that there are very few rotating hard drive manufacturers and their reputations tend to go up and down. With SSDs the problem is counterfeits.

In response to a question about the IT community’s involvement in Ukraine,

Bernard said that there were a lot of Python developers from Ukraine and the community was helping a family to get out. Anonymous is said to be helping while the BBC has enabled Tor on its website; Brian mentioned that the BBC is using short wave.

Bernard demonstrated the stepper motor being controlled by the Raspberry Pi Pico; he can make the stepper motor go at any rate by programming it, in his case, with a Python file. He had bought all the bits separately and now needs to attach it to the camera base.

He added that they are selling the chip in the Pico on its own for people who think they can handle it and David said there are Youtube videos to tell you how to do it.

Brian asked how he programmed it and Bernard said he connected via the USB to download the files; the Pico has lots of different inputs making it suitable for use as a micro-controller. He uses MicroPython which is a subset of Python but with extra libraries to control hardware. Brian asked whether he needed to install anything and Bernard said you have to load the MicroPython interpreter first as with other languages.

If you want a Python web server, there is Django, among others.

Brian shared the following code:

python -m SimpleHTTPServer

### Using Python HttpServer as a simple HTTP Server For python vesion 3 (Check version python -V) Command: python -m http.server 9000 https://www.askpython.com/python-modules/python-httpserver

#### Executing linux commands from a web page https://www.linuxquestions.org/questions/programming-9/executing-linux-commands-from-web-page-and-outputing-it-back-to-the-web-page-724581/

Bernard commented that -m runs a script which in this case creates a sample server; Brian said he only wanted something to put on his local server and Bernard suggested CherryPy which can call an exec program if needed but, as Brian is more familiar with PHP, he should use that instead.

David asked when Bernard would be able to share some pictures taken using the stepper motor and Bernard said, ‘When it is finished and there is a really dark night.’ There are still a lot of practical things to get right.

David reported that BCB has opened its building just like the old days.

Anonymous has leaked documents telling ru sites to repatriate everything suggesting that the Russian government is preparing to cut itself off from the Internet; also the Russian cable snipping ship has launched.

Finally, he shared a Youtube video on Scavenging rechargeable lithium cells from the roadside.