The plan was to run a Postfix secondary MX inside a docker container.
Below are many links that might help me to get that going.
For now, I think this is the shortlist of solutions to try:
- Docker Mailserver
- Mailcow
- Mailu
Archive for the ‘Power User’ Category
Some notes on running Postfix inside a docker container
Posted by jpluimers on 2025/11/14
Posted in *nix, *nix-tools, Cloud, Communications Development, Containers, Development, Docker, Infrastructure, Internet protocol suite, Kubernetes (k8n), postfix, Power User, SMTP | Tagged: 254, 29, 52, 787, DMARC, domains, set | Leave a Comment »
roehling/postsrsd: Postfix Sender Rewriting Scheme daemon
Posted by jpluimers on 2025/11/12
This finally made me perform the (long overdue) migration from Sendmail to Postfix:
The Sender Rewriting Scheme (SRS) is a technique to forward mails from domains which deploy the Sender Policy Framework (SPF) to prohibit other Mail Transfer Agents (MTAs) from sending mails on their behalf. With SRS, an MTA can circumvent SPF restrictions by replacing the envelope sender with a temporary email address from one of their own domains. This temporary address is bound to the original sender and only valid for a certain amount of time, which prevents abuse by spammers.
[Wayback/Archive] roehling/postsrsd: Postfix Sender Rewriting Scheme daemon
Via a long queste to figure out why Gmail every now and then bounces forwarded messages because of Sender Policy Framework (SPF). Below are a few of the links that brought me here in mostly reverse order, but first some links that should help me further on the topic of Postfix virtual aliases.
The sendmail setup had some features not covered below (like a catch-all forward for email to addresses virtual domains not covered by a virtual alias) which I hopefully can cover later.
One thing learned both over the past decades and related postfix material: use separate servers or containers for each of your functions. So do not mix web-hosting, outgoing mail, incoming mail, fail2ban and others on the same server.
Links:
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Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, postfix, Power User, sendmail, SMTP | Tagged: Reload | Leave a Comment »
ASCII Art Archive, my own ASCII signature, plus many FIGlet and TOIlet ASCII font art links
Posted by jpluimers on 2025/11/11
Earlier this year I bumped into [Wayback/Archive] ASCII Art Archive
This brought back instant memories about ASCII art, so in the future expect af few unfinished blog-posts that were in my “if I ever get to it archive” about it.
Let me start with my very limited ASCII art I used in late 1980s and early 1990s newsgroup and LISTSERV mailing list signature I reconstructed from a comp.virus post¹ having some very old contact data²:
o _ _ _ _ _ voice: +31-2522-20908 (18:00-24:00 UTC)
/ (_' | (_) (_' | | snail: P.S.O.
__/ attn. Jeroen W. Pluimers
P.O. Box 266
jeroenp@rulfc1.LeidenUniv.nl 2170 AG Sassenheim
jeroen_pluimers@f521.n281.z2.fidonet.org The Netherlands
Shortly after that, my main source of income moved from the command-line to GUI based tools, so I temporarily kind of lost interest in command-line tools and customs. In that period FIGlet (see below) got created, which I totally missed (though I vaguely remember the 1.0 version being named newban).
The link at the start of this blog post not only pointed me to FIGlet, but also has a lot of examples (like some [Wayback/Archive] ASCII Art Logos – asciiart.eu) of which many by ASCII artist Joan Stark, and also links to JavaScript based tools:
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Posted in ASCII art / AsciiArt, Development, Encoding, Fun, History, JavaScript/ECMAScript, Retrocomputing, Scripting, Software Development | Leave a Comment »
LinuxCND: The Raspberry Pi that ships other Raspberry Pis – Pi Australia
Posted by jpluimers on 2025/11/11
Cool practical application of LinuxCNC: [Wayback/Archive] The Raspberry Pi that ships other Raspberry Pis – Pi Australia
LinuxCNC controls CNC machines. It can drive milling machines, lathes, 3D printers, laser cutters, plasma cutters, robot arms, hexapods, and more.
Via [Wayback/Archive] Frans van Berckel on Twitter: “@geerlingguy So, there is a Raspberry Pi, that ships other Raspberry Pis?”
–jeroen
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Posted in *nix, *nix-tools, Development, Hardware Development, Linux, Power User, Raspberry Pi | Leave a Comment »
How to monitor USB power consumption? – Ask Different
Posted by jpluimers on 2025/11/10
TL;DR: it is impossible on a Mac to accurately measure power usage by attached USB devices. Only a general indication is possible, but it is unreliable.
[Wayback/Archive] How to monitor USB power consumption? – Ask Different
- System Profiler needs manual refresh and is a very rough indication
- iStatMenus is a graph, but not very accurate
- Activity Monitor is even rougher than the above
Related: [Wayback/Archive] View energy consumption in Activity Monitor on Mac – Apple Support (UK)
Via: [Wayback/Archive] macos view usb power usage – Google Search
–jeroen
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Posted in Apple, Mac, MacBook, MacBook Retina, MacBook-Pro, Power User | Leave a Comment »
When Spotlight fails to find some files: mdutil revisited
Posted by jpluimers on 2025/11/07
On my M1 MacBook, somehow Spotlight started to fail returning some indexed files (especially recently added ones would not show up or it would take a very long while for some of them to show up).
So I revisited mdutil and related commands while writing a comment on the YouTube movie [Wayback/Archive] How To Rebuild the Spotlight Index on Your Mac – YouTube which since then vanished, but luckily I saved it and here I amended it with formatting:
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Posted in Apple, Mac, Mac OS X / OS X / MacOS, Power User | Leave a Comment »
Forrest Brazeal on Twitter: ‘Not all “utilization” is created equal…’
Posted by jpluimers on 2025/11/07
From a long time ago, but still fun: [Wayback/Archive] Forrest Brazeal on Twitter: ‘Not all “utilization” is created equal…’
–jeroen
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GitHub – louislam/uptime-kuma: A fancy self-hosted monitoring tool
Posted by jpluimers on 2025/11/05
As promised yesterday¹ because “what’s an open source project without its status page” (and some commercial vendors cough Embarcadero cough could highly benefit from this):
[Wayback/Archive] GitHub – louislam/uptime-kuma: A fancy self-hosted monitoring tool.
Some links (so you can try it for yourself):
- [Wayback/Archive] CryptPad Status (from yesterday’s blog post¹)
- [Wayback/Archive] Uptime Kuma docker site to try yourself
- [Wayback/Archive] Uptime Kuma Demo (starting by choosing a language – many – and database – MariaDB/MySQL or SQLite)
- [Wayback/Archive] Uptime Kuma Status
- [Wayback/Archive] Home · louislam/uptime-kuma Wiki · GitHub
- [Wayback/Archive] uptime-kuma/src/components/notifications at master · louislam/uptime-kuma · GitHub – I like this vast amount of integrations. Some commercial vendors could learn from this.
--jeroen
¹ GitHub – cryptpad/cryptpad: Collaborative office suite, end-to-end encrypted and open-source.
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Posted in *nix, *nix-tools, Development, JavaScript/ECMAScript, Monitoring, Power User, Scripting, Software Development, TypeScript, Vue.js | Leave a Comment »
GitHub – cryptpad/cryptpad: Collaborative office suite, end-to-end encrypted and open-source.
Posted by jpluimers on 2025/11/04
Google Docs alternative for self-hosting or hosted usage: [Wayback/Archive] GitHub – cryptpad/cryptpad: Collaborative office suite, end-to-end encrypted and open-source.
The project started last month 12 years ago in 2014 as the “realtime collaborative visual editor with zero knowlege server” with the commit [Wayback/Archive] and so it begins · cryptpad/cryptpad@1508c7b · GitHub.
Via¹: [Wayback/Archive] Dr. Christopher Kunz: “I’m currently testing Cryptpad for collaborative working.…” – chaos.social
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Posted in *nix, *nix-tools, Cloud, CSS, Development, Google, GoogleDocs, HTML, HTML5, Infrastructure, JavaScript/ECMAScript, Monitoring, Power User, Scripting, Software Development, TypeScript, Web Development | Leave a Comment »
CSV To HTML Converter
Posted by jpluimers on 2025/11/04
While blogging, online tools often beat offline or command-line tools, so here there are:
- [Wayback/Archive] CSV To HTML Converter (and to Wiki table)
- [Wayback/Archive] CSV To Markdown Converter (and to Jira table)
They use JavaScript and do client-side conversion.
There are way more conversion targets (Delimited, Flat File, GeoJSON, HTML Table, JSON, KML, Markdown, Multi-line Data, PDF, SQL, Word, XML, YAML) and operations (Pivot, Transpose, Query with SQL), but the above are what I use most.
–jeroen
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Posted in Blogging, CSV, Development, Power User, SocialMedia, Software Development | Leave a Comment »
The Wiert Corner - irregular stream of stuff 