News archive April 2021 - Koos van den Hout

Yesterday I cycled the same ride as I did last October and a few times since then.

It was a good way to spend a few hours riding on our kings day. I stopped along the way to drink some water and relax. It's still 36 kilometers and the average speed according to the speedometer on my recumbent bicycle was 21.77 kilometer per hour.

More about the HackTheBox & CryptoHack Cyber Apocalypse 2021 I participated in

I found a writeup of the HackTheBox & CryptoHack Cyber Apocalypse 2021 I participated in at How HackTheBoxCTF Exposed The Marriage of Saleae And Hardware - Equus 🐴 (Annie) but I did some things a little different so I decided to share how I did it.

A CTF or Capture the flag is an information security competition where puzzles are offered that have to be solved with techniques from information security. This can range from a simple knowing where to look for clues in data to having to use the latest exploit techniques against systems to get access. The solution is usually a digital 'flag' that proves you solved the puzzle.

A co-worker who has been at the 'receiving end' a few times of the CTF challenges the SURFcert team creates with some help of me invited a number of people at work to the HackTheBox & CryptoHack Cyber Apocalypse 2021.

And I decided to join! We dove into the challenges a number of evenings. I solved a few hardware challenges on my own, and I did parts in solving other challenges. I learned about .sal files and logic analyzers. And I learned cracking a (not too big) public RSA key is doable these days.

Where others wrote bits of python to solve things I used grep and awk. But in the end we got there.

Our team ended in the top 6% which is not bad for doing this on weekday evenings besides our jobs and other bits of life. I posted about this on linkedin in Dutch: Collega Simon Kort BICT nodigde mij uit voor het meedoen in deze CTF.

With a bit of trying and retrying I tuned my home endfed to the FT8 frequency in the 17 meter amateur band. I'm chasing 'slots' on that band: countries I haven't worked on that band before. Today I got the Balearic Islands, Wales, Kenya, Indonesia and Lebanon in the log, all new on this band for me.

Before that there was a nice 10 meter opening during the day, where I worked several European stations.

Nice to see good propagation!

Update 2021-04-25: On Sunday I tried FT8 on 17 meters again, this got me Thailand as a completely new country! And Belarus, Latvia, Lithuania new on the 17 meter band.

Interesting kernel message in Linux today:

[ 3906.977410] ext2 filesystem being mounted at /media/koos/disk supports timestamps until 2038 (0x7fffffff)

So that filesystem (and lots of others) will give issues in 2038. Things need work before that date!

Op artikelen op olduse.net kwam ik een echt VT220 font tegen. Ik dacht gelijk aan het gebruiken van iets vergelijkbaars voor bbs.idefix.net omdat dat natuurlijk eigenlijk in de VGA font stijl moet van de topdagen van de BBS geschiedenis.

Het kostte even zoeken naar het passende font, maar dat is er (vast een extractie uit een IBM VGA rom): Perfect DOS VGA 437 font en daarna wat aanpassingen aan de stylesheet, en nu is bbs.idefix.net in de juiste stijl.

Update: Iets meer werk toch: ik wil momenteel dat om 'historische' redenen de verwijzing http://bbs.idefix.net/ nog werkt maar wel de browser hint om te upgraden, zodat deze pagina met een oude browser te bezoeken is maar een recentere browser vanzelf https wil. De upgradehint ('upgrade-insecure-requests') zorgde er voor dat de http versie een font wilde laden vanaf de https versie en dat moest even aan de ontvangende kant toegestaan worden.

I learned about changes in GPG needing some updates to private keys so I loaded the private key for 0x5BA9368BE6F334E4 in a backup keyring and tried to find out what needs to be done. The explanation at Fixing old SHA1-infested OpenPGP keys seems to have the important parts.

Make sure the preferences are set correctly (no SHA1) and do a 'clear' on the key. I took the chance to change the expiry date to something a bit more in the future, set the e-mail address that I now use as primary and updated the weblink to my homepage to https://idefix.net/.

I also updated the details on PGP - Koos van den Hout so these can be verified.

For almost 20 years I was involved with the running of NTP time servers at work. But the hardware aged and my job is no longer in systems administration and not in the department actually housing the timeservers.

So, time to stop doing it. The pool ntp server has been retracted, DNS names removed and soon I will make one final trip to shut down hardware one last time and remove it from racks. The end for ntp.cs.uu.nl and others.

I still run an NTP server at home which is available in the IPv6 NTP pool. That server also compared itself to one of the servers at work so it has been reconfigured. I added a few upstream servers and made sure all of them are reachable via IPv6.

The log of NTP service at cs.uu.nl was kept, here is the final version:

Date	Event
8 Apr 2021	DNS names for ntp service at cs.uu.nl removed
2 Apr 2021	Announcement posted to system administration mailing list that ntp service at cs.uu.nl will stop
24 Sep 2014	A second stratum-1 ntp appliance is brought on-line, galileo.cs.uu.nl
28 Nov 2011	Fixed the networking for stardate, the full time lab is up and running.
23 Nov 2011	The antenna cable connectors are soldered on which results in a working setup after a few tries. Stardate is better at reporting the state of the power to the GPS antenna, but has no working network. Huygens has working network and serves time to metronoom.
22 Nov 2011	The server ntp.cs.uu.nl is active at its new IP. Our own GPS reference doesn't work yet: we still need to solder the right connectors on the antenna cable. The server is added to the ntp pool and traffic starts to flow a few hours later.
15 Nov 2011	The ntp servers are moved to their new location
14 Nov 2011	The ntp servers are switched off
13 Nov 2011	We retract ntp.cs.uu.nl at its current address from the pool because the serverroom will move physically, the ntp equipment will move to a different location and the IP will change to deal with the traffic better
18 Sep 2011	Stats for doei.cs.uu.nl, five years after withdrawing it from the ntp pool
19 Sep 2010	Stats for doei.cs.uu.nl, four years after withdrawing it from the ntp pool
4 Mar 2010	The turkish adsl provider ttnet falls off the Internet for a few hours, traffic falls from 2000 packets/second to 100 packets/second in that time
22 Jan 2010	We volunteer ntp.cs.uu.nl for the turkish part of the ntp pool. Traffic explodes, peaks over 5000 packets/second
18 Sep 2009	Stats for doei.cs.uu.nl, three years after withdrawing it from the ntp pool
28 Jul 2009	ntp.cs.uu.nl back at full speed in the ntp pool, firewall configuration fixed
15 Jul 2009	rear doors of racks closed again
2 Jul 2009 10:00	serverroom airco has problems with high temperatures (28-30 C), we open rear doors of racks which makes the temperature go down a bit in the racks but the airco still has hard work
Mar 2009	ntp.cs.uu.nl tuned down in the ntp pool to avoid firewall issue
18 Sep 2008	Stats for doei.cs.uu.nl, two years after withdrawing it from the ntp pool
17 Jan 2008	huygens.cs.uu.nl has a GPS reception failure, fixed with a software update
18 Sep 2007	Stats for doei.cs.uu.nl, a year after withdrawing it from the ntp pool
11 Mar 2007	airco failure serverroom
5 Mar 2007	all ntp servers moved to one rack close together for temperature stability
20 Jan 2007	airco failure serverroom
9 Jan 2007	huygens.cs.uu.nl added as stratum-1
23 Dec 2006	airco failure serverroom
29 Nov 2006	powerfailure in our building
1 Nov 2006	metronoom.dmz.cs.uu.nl takes over as ntp.cs.uu.nl and joins pool.ntp.org
~ 24 Oct 2006	antenna cable to stardate.cs.uu.nl reconnected
~ 6 Oct 2006	ntpd on stardate disabled: free running clock starts to differ too much from correct time
~ 25 Aug 2006	antenna cable from stardate.cs.uu.nl disconnected because of building and recabling activities
1 Aug 2006	doei.cs.uu.nl leaves pool.ntp.org
19 Aug 2003	doei.cs.uu.nl joins pool.ntp.org
10 Jan 1999	stardate.cs.uu.nl set up as stratum-1 with GPS time reference

Recently the parts for the NTP ham clock I saw in the Electron magazine arrived: an ESP32 module and a TFT display. It took a bit before I had time to actually do something with them but recently I put the modules on breadboard and started making the needed connections. There are not a lot of those, only 8 wires need to be connected between the ESP32 microcontroller and the TFT display.

After some fiddling it worked and I managed to program it all with the settings I like, such as the right timezone rules for the Netherlands, 24 hour display on both clocks and it fetches the NTP time from the NTP server in the shed so it doesn't rely on outside connectivity.

Now to find a case for it and wire it neatly.

Last weekend was the EA RTTY Contest 2021 edition. I decided to participate because I appreciate the contests organized by the Unión de Radioaficionados Españoles.

Participation time was somewhat limited due to other things happening in the easter weekend. In the end I made 79 contacts and entered my log in the 'SINGLE ALL LOW POWER DX' category. As 'low power' is defined as 'below 100 watts' and my RF amplifier isn't working at the moment this is the fitting category.

Update 2021-05-05: Results are in: 71 valid contacts, 117 qso points and 51 multipliers: rank #225 of the single operator multiband low power DX category.

Another case of having luck and being at the radio at the right time and frequency: I saw a few stations from South Korea show up in FT8. Tried making contact with more than one of them and the second or third station became stronger after a few minutes and with some trying the contact was made with HL5BLI.

It was a really short opening, five minutes later I saw no traces of stations from South Korea.

Update 2021-04-05: And the contact is confirmed on Logbook of the World too.