The Wiert Corner – irregular stream of stuff

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

  • My badges

  • Twitter Updates

  • My Flickr Stream

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,862 other subscribers

Archive for the ‘TCP’ Category

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).

Read the rest of this entry »

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:

Read the rest of this entry »

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:

Read the rest of this entry »

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):

Read the rest of this entry »

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 »

Some ADS-B API link notes (hoping to be able to get from/to airport data from it)

Posted by jpluimers on 2025/10/28

For my link archive initiated because I was trying to find out why ADS-B Exchange does not list originating and destination airports for flights, then on how to get at that data.

It is grouped in a few parts, starting with:

Read the rest of this entry »

Posted in Communications Development, Development, HTTP, Internet protocol suite, JavaScript/ECMAScript, JSON, REST, Scripting, Software Development, TCP, Web Development | Leave a Comment »

GitHub – rbwebdev/lemmings-page-404: My 404 page with a little game of Lemmings

Posted by jpluimers on 2025/08/26

Last week I wrote about Example how not to return a HTPP-500 result: Amazon DE – Tut uns Leid!.

Today I found https://archive.is/undefined which consistently returns a HTTP 404 in the HTTP result.

It reminded me of an old (well, what is old anyway <g>) post Best 404 page ever. back in the days (returning both 404 in the HTTP result and page content) I did not yet archive outgoing links (it took me a few more years to realise many URLs are ephemeral and have queued up a post on that for early next year),  and found out the site has changed since then. Time for archived and updated links, and a repository too as by now the source has been published on GitHub:

Read the rest of this entry »

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

Example how not to return a HTPP-500 result: Amazon DE – Tut uns Leid!

Posted by jpluimers on 2025/08/14

Amazon shows how not to return an HTTP 500 (Internal Server Error) result page: a page with content 500, but result HTTP 200 (OK).

[Wayback] https://www.amazon.de/errors/500

--jeroen

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

In case I need a small 5-port managed switch that can do port-mirroring: GS305E | Easy Smart Managed Essentials Switch | NETGEAR Support

Posted by jpluimers on 2025/08/13

[Wayback/Archive] GS305E | Easy Smart Managed Essentials Switch | NETGEAR Support which can do many-to-one port mirroring.

This is a newer and cheaper hardware revision than the:

  • GS105Ev2 (which is managed and can do port-mirroring, and is confusingly sold as GS105E-200) which in Germany already is end-of-life
  • GS105Ev1 (which is unmanaged and cannot do port-mirroring and is confusingly sold as GS105E-100) which is end-of-life but still sold

Via [Wayback/Archive] Everyone Should Have One of These – EASY Packet Capture! – YouTube who explains very well why you need a switch that can do port-mirroring, then recommends the GS105E but forgets to mention:

  • there are different revisions of the GS105E with the above drawbacks
  • there is GS305E

Related:

Read the rest of this entry »

Posted in Blue team, Communications Development, Development, Ethernet, Hardware, Internet protocol suite, Network-and-equipment, Power User, Red team, Security, Software Development, TCP, UDP | Leave a Comment »

html – What can cause Chrome to give an net::ERR_FAILED on cached content against a server on localhost? – Stack Overflow

Posted by jpluimers on 2025/08/07

On my research list [Wayback/Archive] html – What can cause Chrome to give an net::ERR_FAILED on cached content against a server on localhost? – Stack Overflow

The reason what that back then this would fail (but worked in Firefox and Safari, and because I was in a hurry I didn’t research further): [Wayback/Archive] https://www.office.com/

This site can’t be reached

The webpage at https://www.office.com/ might be temporarily down or it may have moved permanently to a new web address.

ERR_FAILED

Thanks [Wayback/Archive] Mason Wheeler and [Wayback/Archive] Joel Davey.

Details:

Read the rest of this entry »

Posted in Chrome, Communications Development, Development, Encryption, HTTP, https, HTTPS/TLS security, Power User, Security, TCP, TLS, Web Browsers, Web Development | Leave a Comment »

linux – Get final URL after curl is redirected – Stack Overflow (plus some Twitter scraping tricks)

Posted by jpluimers on 2025/08/06

Sometimes I need [Wayback/Archive] Redirect Checker | Check your Statuscode 301 vs 302 on the command-line, so cURL to the rescue: [Wayback/Archive] linux – Get final URL after curl is redirected – Stack Overflow. The relevant portions of answers and comments further below.

TL;DR:

Since I prefer verbose command-line arguments (you can find them at the [Wayback/Archive] curl – How To Use on-line man page) especially in scripts this HTTP GET request is what works with Twitter:

% curl --location --silent --output /dev/null --write-out "%{url_effective}\n" https://twitter.com/anyuser/status/20
https://x.com/anyuser/status/20

This failed (twitter dislikes HTTP HEAD requests):

% curl --head --location --silent --output /dev/null --write-out "%{url_effective}\n" https://twitter.com/anyuser/status/20
https://twitter.com/anyuser/status/20

Notes

Given so many of my scripts now run on zsh, I added the new-line because of command line – Why does a cURL request return a percent sign (%) with every request in ZSH? – Stack Overflow. You can strip that bit.

Note that these do not perform client side redirects, so they do not return the ultimate originating URL https://x.com/jack/status/20 (which was the first ever Tweet on what was back then called twttr) as Twitter on the client-side overwrites window.location.href with the final URL. Similar behaviour for getting the Twitter user handle of a Twitter user ID, more on Twitter tricks below.

Tweet by TweetID trick via [Wayback/Archive] Accessing a tweet using only its ID (and without the Twitter API) – Bram.us.

Further reading (thanks [Wayback/Archive] vise, [Wayback/Archive] Daniel Stenberg, [Wayback/Archive] Ivan, [Wayback/Archive] AndrewF, [Wayback/Archive] Roger Campanera, and [Wayback/Archive] Dave Baird):

Read the rest of this entry »

Posted in *nix, *nix-tools, bash, Batch-Files, Bookmarklet, Communications Development, Conference Topics, Conferences, CSS, cURL, Development, Event, HTTP, Internet protocol suite, JavaScript/ECMAScript, Power User, Scripting, SocialMedia, Software Development, TCP, Twitter, Web Browsers, Web Development | Tagged: | Leave a Comment »