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 ‘TCP’ Category

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 »

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:

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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:

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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:

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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:

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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):

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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 »

Tribal Knowledge? Getting the public keys from github and gitlab users from their username

Posted by jpluimers on 2025/04/03

Learned a while ago: if you have the username from a GitHub or GitLab user, you can download interesting that sometimes can make life easier (but not necessarily more secure):

  • github.com/username.keys gives you their public SSH keys
  • gitlab.com/username.keys gives you their public SSH keys
  • github.com/username.png gives you their profile image

And that there are tools like gh, glab and age that can make direct use of them.

I love Twitter, so thanks for these for teaching me these little tricks:

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Posted in *nix, *nix-tools, ArchiveTeamWarrior, Conference Topics, Conferences, Development, Event, GitHub, GitLab, Internet, InternetArchive, OpenSSH, Power User, Software Development, Source Code Management, SSH, ssh/sshd, WayBack machine | Tagged: , | Leave a Comment »

Some HTTP redirect checking sites compared

Posted by jpluimers on 2025/04/02

 

Every now and then I want to check how a URL redirect, for instance when checking out why a domain failed loading in browsers a while ago because of certificate problems:

The thing was that back then, the site officially did not have a security certificate, but somehow the provider had installed a self-signed one. Most web-browsers then auto-redirect from http to https. Luckily the archival sites can archive without redirecting:

When querying [Wayback/Archive] redirect check – Google Search, you get quite some results. These are the ones I use most in descending order of preference and why they are at that position:

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Posted in *nix, *nix-tools, archive.is / archive.today, Communications Development, Development, Encryption, HTTP, https, HTTPS/TLS security, Internet, Internet protocol suite, ISP, Power User, Security, Software Development, TCP, WayBack machine, Web Development, wget, xs4all | Leave a Comment »

Nartac Software – IIS Crypto

Posted by jpluimers on 2025/03/26

Not just for IIS, but for hardening any Windows system including ones running http.sys (like ADFS): [Wayback/Archive] Nartac Software – IIS Crypto

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Posted in .NET, Communications Development, Development, Encryption, HTTP, HTTPS/TLS security, Software Development, TCP, Web Development | Leave a Comment »