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

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Archive for the ‘Network-and-equipment’ Category

console convert pcap to wav: not easily possible; use the WireShark GUI to do

Posted by jpluimers on 2021/12/01

Wanting a simple way on the console to convert a .pcap file to a .wav file, I searched for [Wayback] console convert pcap to wav – Google Search.

The reason is that [Wayback] fritzcap (written in Python) sometimes crashes while doing the conversion of a phone recording, so then only the .pcap file is available. I still want to figure this out, but given my health situation, I might not be able to in time.

If anyone with Python experience can help, I have failing capture files lying around, and the fritzcap command-line does support decoding [Wayback/]:

# feature/re-add_documentation(+0/-0)* ± python --help
usage: [-h] [-v] [-c] [-d [file [file ...]]] [-m] [-p password]
                   [-u username] [-s] [--config_file path_to_file]
                   [--logging_config path_to_file] [--box_name host_or_IP]
                   [--call_service_port port] [--login_not_required]
                   [--protocol protocol] [--cap_folder path_pattern]
                   [--cap_file file_pattern] [--cap_interface cap_interface]
                   [--after_capture_time time_in_seconds]
                   [--decode_workers_count int]

main arguments:
  -d [file [file ...]], --decode_files [file [file ...]]
                        the list of captured files to decode. All the new
                        captures files will be decode automatically if the
                        --capture switch is set. Read the files from the
                        standard input if the list of files is empty and there
                        is no capture work.

Back to other tooling for decoding VoIPcap/pcap files

Too bad there are no easy solutions. You can use the WireShark GUI to do this, which is OK for infrequent conversions.

Here were some of the results leading me to that conclusion:


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

75 Funny Wifi Names (besides Disconnected and Access Denied)

Posted by jpluimers on 2021/11/26

[WayBack] 75 Funny Wifi Names (as I already run “Disconnected” and “Access Denied”).

Related blog posts:


Posted in Fun, Network-and-equipment, Power User, WiFi | Leave a Comment »

Some links on Wireguard as DHCP clients were not supported back then yet

Posted by jpluimers on 2021/11/12

Wireguard seems more light-weignt and secure than OpenVPN and IPsec. So I’m anxious to know how it is supposed to work for road warriors that often depend on receiving DHCP addresses into the network of the VPN server.

Some links that hopefully get me started to install a Wireguard VPN server and provide services to road warrior clients.

First the Twitter thread that got me investigating:

Then some links I found:


Read the rest of this entry »

Posted in Network-and-equipment, Power User, VPN, Wireguard | Leave a Comment »

In case I ever need to jail-break a Mikrotik device

Posted by jpluimers on 2021/11/02

Some links in case I ever need to jail-break a Mikrotik device:


Posted in Development, Internet, MikroTik, Power User, routers, Software Development | Leave a Comment »

Shodan (via SCADA systems accessible through the internet)

Posted by jpluimers on 2021/10/27

Just 2 years ago I bumped into through [Wayback] Onderzoekers: zestig slecht beveiligde Nederlandse scada-systemen op internet – Computer – Nieuws – Tweakers and saved the entry [Wayback] Shodan (website) – Wikipedia:

Shodan is a search engine that lets the user find specific types of computers (webcamsroutersservers, etc.) connected to the internet using a variety of filters. Some have also described it as a search engine of service banners, which are metadata that the server sends back to the client.[1] This can be information about the server software, what options the service supports, a welcome message or anything else that the client can find out before interacting with the server.

Shodan collects data mostly on web servers (HTTP/HTTPS – ports 80, 8080, 443, 8443), as well as FTP (port 21), SSH (port 22), Telnet (port 23), SNMP (port 161), IMAP (ports 143, or (encrypted) 993), SMTP (port 25), SIP (port 5060),[2] and Real Time Streaming Protocol (RTSP, port 554). The latter can be used to access webcams and their video stream.[3]

It was launched in 2009 by computer programmer John Matherly, who, in 2003,[4] conceived the idea of searching devices linked to the Internet.

It looked promising, but I was really pressed for time (having impromptu arrange all care for my mom, and became even more so when I got diagnosed with rectum cancer later that year), so did not pay much attention apart from registering.

Last year in the midst of my chemos I noted [] Nate Warfield on Twitter: “ The latest Citrix vulnerability looks bad but there might be time to fix them before PoC comes out. The @shodanhq query above might help. ( has more details)… “ (I think via @jilles_com) , so put it on my list of things to look into a bit further.

Since then, I found out a lot of people dislike Shodan and want to blacklist it because they see it as a threat. It feels like people think the internet is like the [Wayback] Ravenous Bugblatter Beast of Traal | Hitchhikers | Fandom

The Ravenous Bugblatter Beast of Traal is a vicious wild animal from the planet of [Wayback] Traal, known for its never-ending hunger and its mind-boggling stupidity. One of the main features of the Beast is that if you can’t see it, it assumes it can’t see you.

(This by the way is one of the reasons for Towel Day – Wikipedia)

Anyway: a few lists of Shodan IPv4 addresses and hostnames, and means to maintain them for the ones interested:

Reality is that the internet is much smarter, so if you block Shodan from seeing you, others from the internet still will and if you have vulnerable services, one day they will be abused. For instance, this personal anecdote:

I forgot I had a port redirection on my router for RDP access a non longer existing Windows system any more. I forgot that this Windows machine had no fixed DHCP-lease while in use (it kept it’s lease as it was always on).

When that machine was long gone, another temporary Windows machine obtained the same internal machine (the router had been rebooted and after reboot hands out previously handed out IP address), and boom: the new Windows machine was bombarded with RDP logon requests.

In the end, the new Windows machine was not compromised, so I was lucky as it could have been.

Back when registering, sent SMTP mail via, so you might want to not blacklist it if you blacklist at all (incidentally, when writing the IP address  servicing that hostname was hosted in The Netherlands: [Wayback] – – Netherlands – IP Volume inc – IP address geolocation).

It is good to think of you use Shodan, as not all usage might be legal where you live or where you travel to.

Some discussion in Dutch on the risks of using Shodan are in the above link. It boils down to:

  • Searching should be OK
  • Accessing the devices found can be totally illegal

That’s basically with anything you find on the internet, for instance by Googling, so nothing new here.

I mainly use Shodan to see if I have any known vulnerabilities exposed. There are not that many ports open, but given the anecdote above, I might screw up again and not be so lucky.

This article has a balanced explanation of Shodan, how you use it, and how to stay safe: [Wayback] How to remove your device from the Shodan IoT search engine.



Posted in Development, IoT Internet of Things, Network-and-equipment, Power User, Security, Software Development, Web Development | Leave a Comment »

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