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

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Archive for the ‘*nix’ Category

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tcp – How can I trigger a script when a certain port becomes available for requests? – Unix & Linux Stack Exchange

Posted by jpluimers on 2018/10/09

Netcat to the rescue waiting for a Windows 10 upgrade to finish (which can take hours):

while ! nc -z 172.22.0.67 3389; do echo "sleeping"; sleep 10; done; echo 'The server is up!'

Via: [WayBack] tcp – How can I trigger a script when a certain port becomes available for requests? – Unix & Linux Stack Exchange, quoting from the answer:

  • nc is Netcat, “the Swiss-army knife for TCP/IP”,
  • -z means: do not send any data, just check if the port is open,
  • while ! nc -z …; do sleep 0.1; done: keep checking and sleeping for one tenth of a second until the port opens up, i.e. Netcat returns with a zero (success) status.

–jeroen

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

Check If A Linux System Is Physical Or Virtual Machine

Posted by jpluimers on 2018/10/08

One day I am going to try to extend this for a few other virtualisation environments and Linux distributions: [WayBack] Check If A Linux System Is Physical Or Virtual Machine

Via: [WayBack] Check If A Linux System Is Physical Or Virtual Machine #Linux – Joe C. Hecht – Google+

–jeroen

Posted in *nix, *nix-tools, Fusion, Hyper-V, KVM Kernel-based Virtual Machine, Power User, Proxmox, View, VirtualBox, Virtualization, VMware, VMware ESXi, VMware Workstation | Leave a Comment »

aha (Ansi HTML Adapter) with clickable URIs

Posted by jpluimers on 2018/10/02

aha is great to generate HTML from ANSI text (i.e. the coloured output on a Linux console).

But it doesn’t generate clickable URIs (it can’t yet by itself as it only looks one character in the future).

The thread at https://github.com/theZiz/aha/issues/20 suggested a case-insensitive regex through sed but the exact suggestion failed for a few reasons I will explain below.

First the bash alias (requires both aha and perl):


#!/usr/bin/env bash
# based on https://github.com/theZiz/aha/issues/20#event-797466520
aha-with-expanded-http-https-urls()
{
aha | perl -C -Mutf8 -pe 's,([^"])((https?|s?ftp|ftps?|file)://.*?)([\s]|\&quot;\s),$1<a href="$2">$2</a>$4,gi'
}

view raw

testssh.sh-through-aha-with-expanded-http(s)-urls.bash

hosted with ❤ by GitHub

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Posted in *nix, *nix-tools, bash, bash, Development, Perl, Power User, RegEx, Scripting, Software Development | Leave a Comment »

Notes on recording audio calls from a Fritz!Box and playing back those captures calls

Posted by jpluimers on 2018/09/28

A while ago, I documented some links for In case I ever need to record calls on my Fritz!Box devices.

By now, I’ve done a bit more investigation: I’ve enabled the call monitor, did some port scans, installed domoticz and got deeper into fritzcap.

Oh and I got packet capturing to work too: Fritz!Box – capture network packets in Wireshark format or ISDN in dtrace format.

A small recap so I don’t forget what I did and what the effects were.

Enabling CallMonitor

[WayBack] Fritzbox – Domoticz showed how to enable the CallMonitor option in your Fritz!Box

  • Dial #96*5* to enable (response “CallMonitor On”)
  • Dial #96*4* to disable (response “CallMonitor Off”)
  • It seems not possible to ask for the current state (enabled/disabled)
  • After it is enabled, the TCP port 1012 on your Fritz!Box is available for tools like [WayBack] Domoticz and fritzcap.

Read the rest of this entry »

Posted in *nix, Fritz!, Fritz!Box, Internet, Linux, openSuSE, Power User, SuSE Linux | Leave a Comment »

On my todo list: experiment with having multiple sendmail queue directories under /var/spool/mqueue

Posted by jpluimers on 2018/09/27

Right now my sendmail configuration handling my domains have one queue directory /var/spool/mqueue which means that each round of the queue processing handles all the outgoing mail in succession.

This is getting less OK because of the increased mail volume over time both on mail that gets in and needs to be forwarded and mail that needs to be bounced for various reasons like SPAM.

So below are some links helping me to sort out various things including having multiple queues (as then each round can handle each queue in parallel).

The default sendmail configuration is one mail queue and I hope to find out for what reason that is.

Background info:

Read the rest of this entry »

Posted in *nix, *nix-tools, Development, Power User, Scripting, sendmail, Software Development | Leave a Comment »

pure-bash-bible/README.md – book for doing things in bash without external tools

Posted by jpluimers on 2018/09/21

[WayBack] pure-bash-bible/README.md at master · dylanaraps/pure-bash-bible · GitHub:

The goal of this book is to document known and unknown methods of doing various tasks using only built-in bash features. Using the snippets from this bible can help remove unneeded dependencies from scripts and in most cases make them faster. I came across these tips and discovered a few while developing neofetch, pxltrm and other smaller projects.

The snippets below are linted using shellcheck and tests have been written where applicable. Want to contribute? Read the CONTRIBUTING.md. It outlines how the unit tests work and what is required when adding snippets to the bible.

See something incorrectly described, buggy or outright wrong? Open an issue or send a pull request. If the bible is missing something, open an issue and a solution will be found.

Via:

—jeroen

Posted in *nix, *nix-tools, bash, bash, Development, Power User, Scripting, Software Development | Leave a Comment »

Not cool: openSuse Tumbleweed switched DHCP clientID algorithm on Raspberry Pi 3, so now all devices get a non-static DHCP address

Posted by jpluimers on 2018/09/15

Not sure in which changeset this happened, but here is one example:

  1. old DHCP client ID 1:b8:27:eb:1a:b1:ec
  2. new DHCP client ID ff:eb:78:a9:4:0:1:0:1:22:6:67:49:b8:27:eb:78:a9:4

The first one was marked static in the DHCP server, which means the Raspberry Pi now did get a different IP address.

This messes up a few places that cannot do proper address resolution.

Anyone who knows where this has changed / is configured?

These did not help finding the cause:

Edit

As commented by Leen below, this is about

Wicked changed its defaults to use this DHCPv6 compatible RFC4361 client-id in favour of the older RFC2132 client-id. However, this has caused some issues with older DHCPv4 servers and existing setups where the client-id stored by the server is used to assign a (static) address. It is recommended to fix this server-side, but still, wicked provides several ways of addressing this issue

So here are some links:

–jeroen

Posted in *nix, Hardware Development, Linux, openSuSE, Power User, Raspberry Pi, SuSE Linux, Tumbleweed | 6 Comments »

https://altd.embarcadero.com/ TLS certificate does not match domain name

Posted by jpluimers on 2018/09/07

One of the domains not yet monitored at embarcaderomonitoring.wiert.me, was the altd download server for ISOs and installers on http and https level. Ultimately you want https, as most of these are about installers, so you do not want any man-in-the-middle to fiddle with them.

TLS on altd fails

Upitmerobot is not yet smart enough to check validity of TLS certificates on https connections.

Chrome, Firefox, Safari, Internet Explorer, wget, curl and ssllabs however are.

altd hides as much from itself as possible

Uptimerobot did not like monitoring the plain http://altd.embarcadero.com/ and https://altd.embarcadero.com/ URLs, because the altd is not browsable, so it tries to hide most of its structure from access. This means they both return an odd response:

Those responses are actually 404 errors (note the - minus sign after curl --trace-ascii: it sends the trace to stdout):

$ wget http://altd.embarcadero.com/
--2018-09-05 10:44:23-- http://altd.embarcadero.com/
Resolving altd.embarcadero.com (altd.embarcadero.com)... 88.221.144.40, 88.221.144.10
Connecting to altd.embarcadero.com (altd.embarcadero.com)|88.221.144.40|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2018-09-05 10:44:23 ERROR 404: Not Found.

$ curl --verbose http://altd.embarcadero.com/
*   Trying 88.221.144.40...
* TCP_NODELAY set
* Connected to altd.embarcadero.com (88.221.144.40) port 80 (#0)
> GET / HTTP/1.1
> Host: altd.embarcadero.com
> User-Agent: curl/7.54.0
> Accept: */*
> 
< HTTP/1.1 404 Not Found
< Server: Apache
< Content-Type: text/html; charset=iso-8859-1
< Content-Length: 16
< Date: Wed, 05 Sep 2018 08:45:57 GMT
< Connection: keep-alive
< 
* Connection #0 to host altd.embarcadero.com left intact
File not found."

$ curl --trace-ascii - http://altd.embarcadero.com/
== Info:   Trying 88.221.144.40...
== Info: TCP_NODELAY set
== Info: Connected to altd.embarcadero.com (88.221.144.40) port 80 (#0)
=> Send header, 84 bytes (0x54)
0000: GET / HTTP/1.1
0010: Host: altd.embarcadero.com
002c: User-Agent: curl/7.54.0
0045: Accept: */*
0052: 
<= Recv header, 24 bytes (0x18)
0000: HTTP/1.1 404 Not Found
<= Recv header, 16 bytes (0x10)
0000: Server: Apache
<= Recv header, 45 bytes (0x2d)
0000: Content-Type: text/html; charset=iso-8859-1
<= Recv header, 20 bytes (0x14)
0000: Content-Length: 16
<= Recv header, 37 bytes (0x25)
0000: Date: Wed, 05 Sep 2018 08:47:19 GMT
<= Recv header, 24 bytes (0x18)
0000: Connection: keep-alive
<= Recv header, 2 bytes (0x2)
0000: 
<= Recv data, 16 bytes (0x10)
0000: File not found."
File not found."== Info: Connection #0 to host altd.embarcadero.com left intact

This is also the reason that WayBack does not want to archive that link, but it can be archived at [Archive.is] https://altd.embarcadero.com/.

Luckily, a Google search for site:altd.embarcadero.com revealed there is a non-installer file short enough (~72 kibibytes) for Uptime robot to check, so it now verifies it can access these:

–jeroen

Read the rest of this entry »

Posted in *nix, *nix-tools, cURL, Encryption, HTTPS/TLS security, Monitoring, Power User, Security, Uptimerobot, wget | Leave a Comment »

Some Linux mail solutions

Posted by jpluimers on 2018/09/07

Too bad most of them are very picky to the Linux distributions they run on.

–jeroen

Posted in *nix, Linux, openSuSE, Power User, SuSE Linux | Leave a Comment »

I am on a Mac that is bound to an AD Domain. The AD Domain has a 90 days pass…

Posted by jpluimers on 2018/08/27

[WayBack] I am on a Mac that is bound to an AD Domain. The AD Domain has a 90 days password expiration policy. When will my password expire? $ cat bin/is-passwor… – Kristian Köhntopp – Google+

For my link archive:


#! /bin/bash —
validFor=$(( 90 * 86400 ))
domainPrefix='/Active Directory/DOMAIN/doma.in/"
lastPW=$(dscl "/$domainPrefix" -read /Users/$USER | awk '/SMBPasswordLastSet/ { print $NF }')
unixPW=$(($lastPW / 10000000 – 11644473600 + $validFor))
expireDate=$(date -r $unixPW)
echo "Password expires $expireDate"

view raw

is-password-good.sh

hosted with ❤ by GitHub

Script copied to [WayBack] Kristian Köhntopp: I am on a Mac that is bound to an AD Domain. The AD Domain has a 90 days password expiration policy. When will my password expire?  · GitHub

–jeroen

Posted in *nix, Apple, bash, Development, Mac, MacBook, MacBook Retina, MacBook-Air, MacBook-Pro, MacMini, Power User, Scripting, Software Development | Leave a Comment »

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