The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Internet protocol suite’ Category

Some links on finding the redirection target of a URL from within a web-browser

Posted by jpluimers on 2026/08/26

Likely what I want is not possible because of CORS or CSP (both security features, often mixed up in writings), but just in case below are some links I found.

The problem at hand was that I wanted to use the functionality of a site like [Wayback/Archive] Redirect Checker | Check your Statuscode 301 vs 302, but on the client side because sometimes redirects depend on locality (for example, but not limited to, AliExpress sites).

Thinks like these fail with CSP errors like Refused to connect to 'https://t.co/Ui4Wmesq1j' because it violates the following Content Security Policy directive: "connect-src chrome://resources chrome://theme 'self'".:

var xhr = new XMLHttpRequest();
xhr.onload = function() {
  if (this.status < 400 && this.status >= 300) {
    console.log('request redirects to ' + this.getResponseHeader("Location"));
  } else {
    console.log('request does not redirect');
  }
}
xhr.open('HEAD', 'https://t.co/Ui4Wmesq1j', true);
xhr.send();

Links – many of them mentioning CORS, but few CSP:

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Posted in Communications Development, Development, HTTP, Internet protocol suite, Software Development, TCP, Web Development | Tagged: , , | Leave a Comment »

Julia posted a challenge: Implement DNS in a weekend

Posted by jpluimers on 2026/07/23

Missed the original announcement of [Wayback/Archive] Implement DNS in a weekend

Even after a few years, it is still a fun project to take on.

Via [Wayback/Archive] Julia Evans on Twitter: “it’s fun to see all the different languages people are implementing DNS in a Weekend in (implement-dns.wizardzines.com) — so far I’ve seen C#, Rust, Kotlin, Clojure, Golang, Elixir, Typescript, and Python”

More:

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Posted in Communications Development, Development, DNS, Internet, Software Development, TCP, UDP | Leave a Comment »

Full logging of the HTTPS connection in your browser – jawj/subtls: A proof-of-concept TypeScript TLS 1.3 client

Posted by jpluimers on 2026/07/08

This is cool: [Wayback/Archive] jawj/subtls: A proof-of-concept TypeScript TLS 1.3 client showing both the bytes and the decoded meaning of the data structures they form.

A demo is at [Wayback/Archive] https://subtls.pages.dev/

See this page fetch itself, byte by byte, over TLS

Based on / related:

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Posted in Communications Development, Development, HTTP, Internet protocol suite, SMTP, TCP, TLS, Web Development | Leave a Comment »

RubyConf Mini 2022: Keynote: Learning DNS by Julia Evans – YouTube

Posted by jpluimers on 2026/06/18

[Wayback/Archive] RubyConf Mini 2022: Keynote: Learning DNS by Julia Evans – YouTube

Via [Wayback/Archive] 🔎Julia Evans🔍 on Twitter: “Just noticed that the recording of my keynote “Learning DNS in 10 Years” from @RubyConfMini is up!”

–jeroen

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Posted in Communications Development, Development, DNS, Internet, Internet protocol suite, Power User, Software Development, TCP, UDP | Leave a Comment »

Ontdek alle Nederlandse bedrijven uit het Handelsregister – OpenKvK.nl

Posted by jpluimers on 2026/05/12

Weet altijd waar je zaken mee doet: [Wayback/Archive] Ontdek alle Nederlandse bedrijven uit het Handelsregister – OpenKvK.nl

Er is een API van in totaal 4 datasets volgens [Wayback/Archive] API documentatie – overheid.io:

Gerelateerd: [Wayback/Archive] Hacken voor Democratie | Hack de Overheid!

--jeroen

Posted in Communications Development, Development, HTTP, Internet protocol suite, REST, Software Development, TCP | Leave a Comment »

Need to find a “smart” broken/404 link checker

Posted by jpluimers on 2026/04/15

Most of the links from my blog get accompanied with Wayback or Archive.today links, but some don’t.

For those, I need to find a broken/404 link checker which I already hinted at in scr.im « Share your email in a safe way. Get less spam.

Some links that hopefully help me:

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Posted in Development, HTTP, Internet protocol suite, Power User, Software Development, TCP, Web Development | Leave a Comment »

A few pfSense quirks I got used to over the years

Posted by jpluimers on 2026/01/06

Everytime when installing a pfSense router from scratch, I seem to re-learn a few of the below quirks. So it was finally time to document them (:

Quite a few of my pfSense configurations are just doing routing between various networks, should not provide DHCP leases and do not always need or have a WAN connected (i.e. they are LAN-only).

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Posted in Communications Development, Conference Topics, Conferences, Cyberchef, Development, DHCP, Encoding, Event, Hardware, HTTP, Internet protocol suite, MikroTik, Network-and-equipment, pfSense, Power User, routers, Software Development, SSH, TCP, TLS, UDP | Tagged: | Leave a Comment »

ssl – Why was 398 days chosen for TLS expiration? – Stack Overflow

Posted by jpluimers on 2026/01/01

Cool, since I switched to Let’s Encrypt a long while ago, I missed that various tools now require TLS expiration be no longer than 398 days away (and preferably even 397 days).

So I also missed the reason for that specific number of days. [Wayback/Archive] ssl – Why was 398 days chosen for TLS expiration? – Stack Overflow (thanks [Wayback/Archive] stevendesu and [Wayback/Archive] user10063)

answers it:

366+31+1 = 398 days

It equals one leap year + one month + “a little room to handle the messiness of dates.”

then posts a lot of quotes from references to the history on how that reason came to be. I have archived and listed the links below.

Most of the discussion was during a very hectic time in life: after a single sided bad accident my mentally retarded brother was in and assisting him during his recovery period, I developed cancer and had extensive treatments against it. All the more reason for missing all this:

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Posted in Communications Development, Development, Encryption, https, HTTPS/TLS security, Internet protocol suite, Let's Encrypt (letsencrypt/certbot), Power User, Security, TCP, TLS | Tagged: , | Leave a Comment »

Bufferbloat, The Internet, And How To Fix It | Hackaday

Posted by jpluimers on 2025/12/26

Anxious to see how many routers have improved their algorithms to prevent Bufferfloat.

[Wayback/Archive] Bufferbloat, The Internet, And How To Fix It | Hackaday

The following YouTube videos in it are embedded below the blog signature:

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Posted in Communications Development, Development, Internet protocol suite, LifeHacker, Network-and-equipment, Power User, routers, TCP, UDP | Tagged: , , , , , | Leave a Comment »

When you get an error 103 establishing an SFTP

Posted by jpluimers on 2025/12/10

A while ago I got an error 103 using both Beyond Compare. That did not whos the connection log or error reason, but WinSCP did: it mentioned unexpected output during the logon.

I got reminded that I had already solved this error before via [Wayback/Archive] SSH login works but SFTP login doesn’t – Server Fault (thanks [Wayback/Archive] qreon and [Wayback/Archive] Paulus):

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Posted in *nix, *nix-tools, bash, bash, Beyond Compare, Communications Development, Development, Internet protocol suite, Power User, Scripting, SFTP, Software Development, SSH, TCP, Windows, WinSCP | Leave a Comment »