Home
Non-daily weblog
Exchange | Board
Files for download
Workshop tutorials
W3 | Directory & Wiki
Artwork : AI createdSetup & config options
Suitable power supply
RasPi & sFTP file transfer
Home network print server
Home network scan server
Mesh : home Lan USB drive
Explore hard & software
UFW firewall explained
Secured by fail2ban server
Software packaging & PPA
Apache 2.4+ LAMP server
https web server : port 443
Varnish caching proxy
Module : cgi & perl
Module : geoip
Modules : php & mysql
http*s error handling
Server : conditional logging
TL-domain & dynamic DNS
Webalizer log analyser
Defeat referrer spam
robots.txt & xml sitemaps
Server : .htaccess handling
The game & not the islands
Setup & config options
North Atlantic : Macaronésia
Nine Azorean islands
Madeiran archipelago
POI on Madeira island
Streaming media
Contact details
Privacy policy & terms
Host traffic elicitation🚫 No ads & tracking
📅 The non-daily weblog published
📄 ➊
Caution 
Proprietary and untested third-party software sources (Linuxes) can threaten the system.
Verifying a good or bad bot
Verify that a bot/crawler accessing your server is an official and common like Bingbot, Googlebot, Duckduckgo, Slurp etc. by using the DNS lookups. This helps you identify other bots or malicious agents that may be accessing your site while claiming to be common bot. You can use command line tools to verify bots by following these steps.
- Locate the accessing IP address from your server logs (e.g. /var/log/apache2/access.log).
- Use the host command to run a reverse DNS lookup on the IP address.
- Verify the retrieved domain name is a subdomain of crawl.anybot.com.
- Use the host command to run a forward DNS lookup on the retrieved domain name.
- Verify the returned IP address is identical to the original IP address from your server logs.
- Locate the accessing IP address from your server logs.
- Use the host command to run a reverse DNS lookup on the IP address.
- Verify the retrieved domain name is a subdomain of crawl.anybot.com.
- Use the host command to run a forward DNS lookup on the retrieved domain name.
- Verify the returned IP address is identical to the original IP address from your server logs.
One demonstration:
root@dosboot:/home/pi# host 12.34.56.789
root@dosboot:/home/pi# 789.56.34.12.in-addr.arpa domain name pointer 12-34-56-789.crawl.amazonbot.amazon
root@dosboot:/home/pi# host 12-34-56-789.crawl.amazonbot.amazon
root@dosboot:/home/pi# 12-34-56-789.crawl.amazonbot.amazon has address 12.34.56.789
27-Mar 2024
Raspberry Pi 5 sooner than expected
The offer makes one wonder, because the Pi 5 was not supposed to be released until next year. A little further research then confirmed that the Pi 5 should already be available from 23 October 2023 and with new specification in the 4 and 8 GByte DDR4 RAM variants.
Three new chips are integrated on the board of the Pi 5. The first is the SoC, which again comes from Broadcom, is called BCM2712 and is a 64-bit, 4-core Cortex-A76 with up to 2.4 GHz.Its predecessor, the BCM2711, did not exceed 1.5GHz, which represents an enormous increase from one generation to the next. The GPU is an integrated VideoCore VII and promises dual 4Kp60 HDMI display output with HDR support.
The Renesas DA9091 is a third new chip on the small board that takes care of the power supply, offers a real-time clock (RTC) and realises a long-cherished wish of many users. The new Pi 5 will have a soft button for switching on and off. 
Raspberry Pi Foundation
01-Oct 2023
Raspberry Pi is considerably cheaper again
After various variants of the popular ARM-based single-board computer Raspberry Pi were enormously expensive and at the same time poorly available in the past few years, the supply situation has now improved significantly again. While a Raspberry Pi 4 Model B with 4 GB RAM was still hardly available at the beginning of May - and if at all, only for around 170 euros, the same model is now listed again in the price comparison for just under 70 euros and immediately available. This means that the single-board computer has almost returned to the price level at which it was traded in the summer of 2021.
The price drop comes as no surprise after Eben Upton, CEO of the Raspberry Pi Foundation, declared back in June that production would be massively ramped up this year. According to this, the organisation had previously shipped about 400,000 units per month. However, a large part of these are said not to have arrived at retailers or end users at all, but directly at commercial buyers.
07-Aug 2023
TOR exit nodes blocking
TOR exit nodes can be used by anonymous attackers from around the globe to launch attacks against networks.
As a preventive measure, TOR exit notes are currently blocked here as well. If you also want to do this, you can do it with a few lines in the htaccess file. If you also want to do this, you can do it with a few lines in the .htaccess file.
<RequireAll> Require all granted Require not host anonym cloud exit local node onion privacy scan tor vpn vps </RequireAll>
09-May 2023
Canonical extends its Ubuntu Pro
Since last year, Canonical has been offering Ubuntu Pro as part of its Ubuntu Advantage subscription model, extending support to ten years for enterprise customers. The offer, which is still in the beta phase, has now been extended to include a free variant for end users.
In future, private users and small commercial enterprises with up to five computers will also be able to access Ubuntu Pro - free of charge. Ubuntu Pro is available for supported Ubuntu LTS version, starting with Ubuntu 16.04 ESM up to Ubuntu 22.04 LTS. The interim versions, which are only supported for nine months, are excluded.
With the free subscription to Ubuntu Pro, security coverage for critical, high and medium vulnerabilities and susceptibilities (CVEs) is extended to thousands of applications and toolchains. These include Ansible, Apache Tomcat, Apache Zookeeper, Docker, Drupal, Nagios, Node.js, phpMyAdmin, Puppet, PowerDNS, Python 2, Redis, Rust, WordPress, ROS and others. Ubuntu Pro also includes compliance management tools such as Ubuntu Security Guide (USG), a tool that facilitates hardening and auditing with compliance profiles such as certified CIS benchmark tools and DISA-STIG profiles on Ubuntu systems. Ubuntu Pro users can also use FIPS 140-2 certified encryption.
Free support for up to five machines can be set up on the Ubuntu Pro website. For Ubuntu Community members, the offer is extended to 50 computers. A 30-day free trial of Ubuntu Pro is available for enterprise customers. Paid packages are priced at USD 25 per year for workstations and USD 500 per year for servers. Additional services such as 24×7 support can be added if required.
14-Feb 2023
DeltaChat | Delta Chat Messenger Client
Delta Chat is a messaging app that works over e-mail
Delta Chat is a free instant messaging client for smartphones and PCs. It is available for the operating systems Android, iOS, Linux, Windows (also portable) and macOS. The protocol is based on IMAP and SMTP. By using the IMAP and SMTP e-mail protocols, Delta Chat is compatible with any conventional e-mail client. The system thus manages completely without its own servers. The user is no longer limited in the use of his messenger to users who use the same service, but could also use it to reach users who use other chat clients, since the underlying messaging protocol is the open e-mail standard.
In addition to instant messaging, it is possible to exchange photos, contacts, disappearing (temporary) messages, voice messages, live locations, as well as all other file formats that are also supported by conventional e-mail. This is also possible in open or encrypted group chats. However, audio and video chats are not possible with the email protocol due to the system, but external video chat instances (e.g. Jitsi Meet) can be integrated. Through the use of specially developed web apps and their open concept, the range of functions can be expanded almost indefinitely. For security reasons, these run in a sandbox. Delta Chat is multi-client capable. Both sent and received messages are synchronised between the individual clients. For this purpose, the private key can be securely transferred to additional clients using Autocrypt.
The current installation packages can be obtained free of charge through the Google Play Store (Android), F-Droid (Android), App Store (iOS), Microsoft Store (Windows) and via the developer website (Android, Linux, Windows and macOS). Development initially started with the Android app, but the versions for Apple, Windows and Linux followed without much delay.
Delta Chat implements the IMAP protocol known from e-mails on the transmission side. It is common for the chat client to create a folder in the folder of the mail server used, in which the messages are stored. This way, the mailbox can also be used for normal e-mail traffic without flooding the inbox with unread chat messages. To prevent messages from "disappearing" through presorting with the help of server-side filters or in the spam folder, Delta Chat checks all IMAP folders for chat messages at regular intervals. Many servers are equipped with flood protection that limits the number of messages within a defined time and are therefore unsuitable for chats. These characteristics of the e-mail system require a suitable configuration on the server side and Golem notes that e-mail is virtually the prime example of asynchronous communication, whereas chat programmes must be designed for real-time communication. It is therefore unlikely that COI (Chat over IMAP) could replace common messengers.
Complete and automatic end-to-end encryption with OpenPGP is used. The key pair is generated automatically during the initial setup or an existing key can be imported. Public keys are transferred using autocrypt. All messages between autocrypt-enabled clients are encrypted and signed end-to-end in the default setting. Whether transport encryption is used in addition to end-to-end encryption depends on the respective e-mail provider. The source code for all clients can be found on GitHub.
30-Dec 2022
Raspberry Pi to be more available soon
The poor availability and the fantasy prices are due to the global supply chain crisis, which kept us on tenterhooks throughout the year when we wanted to buy technical devices. Those who want to invest in home automation, for example, are also having a bad experience with availability.
An unpleasant side effect of the supply chain crisis, according to Upton, is an increase in the cost of pretty much every component that goes into a Raspberry Pi, from circuit boards to connectors to silicon. The increases were initially absorbed internally, apart from the Compute Module 4, which saw a flat $5 price increase for all variants, and the 2GB variant of the Raspberry Pi 4, which saw its original $45 price reinstated. Now the price of the Zero models is also increasing. The Zero will cost $10 instead of $5, and the price of the Zero W will rise from $10 to $15.
There probably won't be a RasPi 5 next year, Upton said. A new model is not expected before 2024, he said, because 2023 is supposed to be a year of recovery, as the events of the last few years not only led to missing components, but also to interruptions in the development of new platforms. When asked about a RasPi based on RISC5, Upton said that one has to be realistic here. A voluntary departure from the ARM platform is not to be expected in the foreseeable future for cost reasons.
However, there could soon be changes in ARM's business model that result in higher licence fees. In addition, the combination of ARM processors with GPUs or AI accelerators from other manufacturers is to be limited. This is information that came to light on the sidelines of the legal dispute between ARM and licensee Qualcomm. Should this happen, the Raspberry Pi Foundation would of course also be affected.
30-Dec 2022
OpenShot 3.0 released
The popular video editor has received numerous improvements in the new version. These range from higher stability to a better timeline, a lower memory requirement and the user manual.
The developer of the free video editor OpenShot, Jonathan Thomas, informs in a blog post about the new features of version 3.0, which has been worked on intensively over the past 12 months, so that the video editor now offers over 1000 improvements and bug fixes.
Highlights of this release include: Improved stability and memory usage, better real-time video playback, work on the timeline and usability, the ability to export multiple clips and videos at once, and a revised user guide and updated translations. Added to this is extended support for video formats, Blender 3.3 and 4K displays and monitors with high resolution.
One of the biggest and most noticeable changes in OpenShot 3.0 is the improved video preview, which results in smoother rendering and fewer freezes and pauses during preview. To understand why playback is so much smoother, the developers had to take a closer look at the decoding engine. Then the decoder was redesigned to be much more resilient to missing packets and timestamps, and to better detect when video or audio data is missing, so that playback can now continue without interruption.
12-Dec 2022
The LibreOffice bookshelf | All manuals
The LibreOffice library contains all the manuals for the free office suite. These are regularly updated to the new versions of the software. Now the Calc-Guide is the first book for the 4.7 series to be published in English.
Besides bug fixes and an improved description of conditional formatting, sparklines are also described. The books can be bought, downloaded as PDFs or read online. Speaking of sparklines; if you have never heard of them, here is a short demonstration.
https://books.libreoffice.org/en/ - The LibreOffice bookshelf
https://books.libreoffice.org/pt-br/ - Estante do LibreOffice
https://books.libreoffice.org/es/ - Librería de LibreOffice
Sparklines are mini diagrams that can be placed in a cell. To create them, select a range of values and choose from the menu: Insert => Insert Sparkline. There you see the selected value range and can specify in which cell the sparkline should be shown (output range). You can see the value range (temperature values for one year for example) and two sparklines as a bar and line chart. In the properties window of the sparkline there are further options for displaying the mini-diagrams.
14-Oct 2022
SEO detailed knowledge | 404 or 410 ?
The detailed question of whether an HTTP code 404 or 410 is better for quickly removing pages from the index is often asked. Which is better? And is that relevant at all? First of all, every request to a web server returns an HTTP code (status code). Ideally, this is then a 200 code, which signals that the information could be returned as requested. However, if the information cannot be found under the desired URL and no redirection has been set up, a 4xx code is returned.
When asking whether it has to be 404 or 410, you should look carefully at what the codes mean in each case. 404 = Not Found: The content was not found. 410 = Gone: The content was not found because it is gone.
Let's start with the similarities. The crawler (Googlebot) will retrieve a URL and get a 404 or 410 returned. The page then disappears very quickly from the search results lists. It is therefore relatively unlikely that you will click on a URL that no longer exists in Google results. The difference, however, lies in the meaning and the crawler behaviour. With 410, it is clear: the resource is gone and will not come back. 404 means: It is gone, but this does not indicate whether this may have happened unintentionally and whether the resource will be available again tomorrow.
Google has communicated in the past that a page that has a 404 code for the first time since the last crawl receives a short "protection". This means that the crawler does not "believe" this code at first and checks it again soon. With a 410, however, it is assumed that it is already correct. In case of doubt, a 410 can help to get a page out of the index more quickly. With a 404, the crawler will check a few more times (in the following days/weeks/months) to see if the resource still exists. With a 410, this also happens, but perhaps a little less frequently.
The question of whether a 404 or 410 is used therefore has no influence on the final result (page no longer appears in the search results), but only on how much crawl budget is wasted on the pages that no longer exist.
So if it's a typical case of deleting two HTML pages or three PDF documents, the additional effort (404 vs. 410) for the crawler will be so small that it will in fact have no influence at all on the crawl budget. If you delete thousands of pages at once, you might achieve better results with a 410 HTTP code - but always in relation to the crawl budget. And that is a negligible issue for most websites.
01-Oct 2022
📄 ➊