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

Firefox: disable DNS over HTTPS (which they call TTR)

Posted by jpluimers on 2021/08/03

There are many reasons to disable DNS over HTTPS (DoH), of which enough are discussed in the links below.

Disabling DoH always talks about setting TTR (the abbreviation Mozilla uses for it) to 5 (like [WayBack] Thread by @isotopp: “Firefox is about to break DNS by enabling DNS-over-HTTP by default […]”), but hardly ever explains the meaning of 5, or any other potential values.

After some searching, I found [WayBack] Firefox disable trr | Knowledge Base:

  • 0: Off by default
  • 1: Firefox chooses faster
  • 2: TRR default w/DNS fallback
  • 3: TRR only mode
  • 5: Disabled

I imagine the setting we’re all looking for is: user_pref(“network.trr.mode”, 5); (emphasis mine)

It pointed me to [WayBack] Trusted Recursive Resolver – MozillaWiki:

Read the rest of this entry »

Posted in Cloud, Cloudflare, Communications Development, Development, DNS, Firefox, Infrastructure, Internet protocol suite, Power User, TCP, Web Browsers | Leave a Comment »

Filezilla: figuring out the cause of “Connection timed out after 20 seconds of inactivity”

Posted by jpluimers on 2021/07/21

On one of my Raspberry Pi boxes, somehow I could not access files over SFTP (SSH File Transfer Protocol) via FileZilla.

I would consistently get this error:

"Connection timed out after 20 seconds of inactivity"

Figuring the exact cause took a while.

TL;DR: SFTP uses an interactive non-login shell, then interprets the output from that shell. For that kind of shell, ensure few or none scripts run that output text.

These links finally got me to the cause

Read the rest of this entry »

Posted in *nix, *nix-tools, bash, bash, Communications Development, Conference Topics, Conferences, Development, Event, Internet protocol suite, Power User, Scripting, SFTP, Software Development, SSH, TCP | Leave a Comment »

Many http headers via 🔎Julia Evans🔍 on Twitter: “some security headers… “

Posted by jpluimers on 2021/07/20

An image on CORS will follow; likely more on related topics too. [WayBack] 🔎Julia Evans🔍 on Twitter: “some security headers… “ about:

Interesting comments in the thread.

More to follow: [Archive.is] 🔎Julia Evans🔍 on Twitter: “going to talk about CORS headers on a different page because that’s a Whole Thing but i’d love to know what else I left out / got wrong here :)” including these:

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Posted in Communications Development, Development, Encryption, HTTP, https, HTTPS/TLS security, Internet protocol suite, Power User, Security, TCP | Leave a Comment »

JSONPlaceholder – Fake online REST API for developers

Posted by jpluimers on 2021/03/25

A great way for testing REST JSON calls is using the [WayBack] JSONPlaceholder – Fake online REST API for developers:

Fake Online REST API for Testing and Prototyping
Serving ~200M requests per month
Powered by JSON Server [WayBack] + LowDB [WayBack]

It is like [WayBack] Placeholder.com: Placeholder Images Done For You [JPG, GIF & PNG] but for JSON and supports both CORS and JSON-P for cross domain requests.

You can either use that site (which has a predefined set of REST calls) or the basic [WayBack] My JSON Server – Fake online REST server for teams that allows you to respond it to a db.json file from github:

Fake Online REST server for teams

Create a JSON file on GitHub

github.com/user/repo/master/db.json
{
  "posts": [
    {
      "id": 1,
      "title": "hello"
    }
  ],
  "profile": {
    "name": "typicode"
  }
}

Get instantly a fake server

my-json-server.typicode.com/user/repo/posts/1
{
  "id": 1,
  "title": "hello"
}

Related

Documentation

There is basic documentation at the repository [WayBack] GitHub – typicode/jsonplaceholder: A simple online fake REST API server:

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

🔎Julia Evans🔍 on Twitter: “ssh tips… “

Posted by jpluimers on 2021/01/08

Great work by [WayBack]  🔎Julia Evans🔍 on Twitter: “ssh tips… “

[WayBackssh tips JPG

Via:

Some more tips:

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Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, Power User, SSH, ssh/sshd | Leave a Comment »

Remote access to the Embarcadero License Center via SSH tunnel – twm’s blog

Posted by jpluimers on 2020/08/10

Thomas basically did all the research on the forwarding needed for ELC (formerly Belise/Elise), then showed the PuTTY equivalent to ssh user@remote -L5567:192.168.1.200:5567:

[WayBackRemote access to the Embarcadero License Center via SSH tunnel – twm’s blog

Via: [WayBack] Once you have set up an Embarcadero License Center (ELC) for your company (with network named user or concurrent licenses) you will need network access … – Thomas Mueller (dummzeuch) – Google+

Related: [WayBack] Introducing the Embarcadero License Center – ELC

–jeroen

 

Posted in *nix, Communications Development, Delphi, Development, Internet protocol suite, Licensing, Power User, Software Development, SSH, ssh/sshd | Leave a Comment »

ssh_config section order is important: the first setting obtained from a Host/Match section applies

Posted by jpluimers on 2020/06/12

Often, configuration files work like this:

  • global settings are at the top
  • detailed settings are further on, overwriting global settings

Not for ssh_config though, so I was right writing I should read more on it in Good read for starting to intermediate ssh users is “SSH Essentials: Working with SSH Servers, Clients, and Keys | DigitalOcean” and pointers to more advanced reading material.

So here is how ssh_config does it as per man page at [WayBack] ssh_config(5) – OpenBSD manual pages and [WayBack] ssh_config — OpenSSH SSH client configuration files at Linux.org:

     For each parameter, the first obtained value will be used.  The configuration files contain sections separated
     by “Host” specifications, and that section is only applied for hosts that match one of the patterns given in the
     specification.  The matched host name is the one given on the command line.

     Since the first obtained value for each parameter is used, more host-specific declarations should be given near
     the beginning of the file, and general defaults at the end.

This means a section Host * needs to come at the end.

I got that wrong and it took me the better half of a morning to figure out the cause of a connection problem ending in this:

debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred publickey
debug3: authmethod_lookup publickey
debug3: remaining preferred:
debug1: No more authentication methods to try.

Somehow, the identity file was never used to try public key authentication at all because of the ssh_config order in ~/.ssh/config.

I’m not the only one confused, as during the search for the cause with “remaining preferred” “No more authentication methods to try.”:

Maybe now I should step up from manually editing the ssh_config file and use [WayBack] GitHub – moul/advanced-ssh-config: make your ssh client smarter to generate it for me.

–jeroen

Posted in *nix, *nix-tools, Communications Development, Development, Internet protocol suite, Power User, SSH, ssh/sshd, TCP | Leave a Comment »

Authssh from Windows

Posted by jpluimers on 2020/05/22

Running autossh from Windows is still on my list, so here are a few links:

–jeroen

Posted in Communications Development, Development, Internet protocol suite, Power User, SSH, TCP, Windows | Leave a Comment »

On my list of things to try: GitHub – arthepsy/ssh-audit; SSH server auditing

Posted by jpluimers on 2020/05/18

This looks like an ssh equivalent to testssl.sh: [WayBack] GitHub – arthepsy/ssh-audit: SSH server auditing (banner, key exchange, encryption, mac, compression, compatibility, security, etc).

It is on my list of things to try, so I’ve put a watch on the repository changes.

–jeroen

Read the rest of this entry »

Posted in Communications Development, Development, Encryption, Internet protocol suite, Power User, Security, SSH, TCP | Leave a Comment »

Insomnia REST Client

Posted by jpluimers on 2020/05/12

[WayBack] Insomnia REST Client  A powerful REST API Client with cookie management, environment variables, code generation, and authentication for Mac, Window, and Linux.

Source code at [WayBack] GitHub – getinsomnia/insomnia: The most intuitive cross-platform REST API Client 😴.

Via: [WayBack] Paw is nice – The Isoblog.

–jeroen

 

 

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