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Koos van den Hout

Welcome. This is my homepage where I write about my opinion, projects, things I note, things I try and other random stuff. Newsitems have tags for a bit of structure.

Latest news/thoughts/geeking/rants/notablog

2015-02-26 (Remember when DNS manuals told you that a CNAME of a CNAME was a bad idea? It still seems to be when...) 1 day ago
Google+Koos van den Hout : Remember when DNS manuals told you that a CNAME of a CNAME was a bad idea? It still seems to be when your DNS name is also used by other devices. Our smart TV decided it had no working Internet connection and the fix is to give it a DNS answer without 3 CNAMEs in it.
2015-02-25 Samsung TV decides the Internet is broken 2 days ago
Currently our Samsung 'smart' TV is convinced the Internet is broken and refuses to start any of the applications. According to some network protocol sniffing the TV decides this purely based on a DNS query for www.samsung.com which takes an interesting CNAME tour. According to what I can find this hasn't changed when the smart TV stopped working so this must be something in the software in the TV itself.
; <<>> DiG 9.4.2-P2.1 <<>> www.samsung.com a
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39167
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 0

;www.samsung.com.               IN      A

www.samsung.com.        253     IN      CNAME   www.samsung.com.edgekey.net.
www.samsung.com.edgekey.net. 3171 IN    CNAME   www.samsung.com.akadns.net.
www.samsung.com.akadns.net. 253 IN      CNAME   china-www.samsung.com.edgekey.net.
china-www.samsung.com.edgekey.net. 2765 IN CNAME china-www.samsung.com.edgekey.net.globalredir.akadns.net.
china-www.samsung.com.edgekey.net.globalredir.akadns.net. 853 IN CNAME e1722.g.akamaiedge.net.
e1722.g.akamaiedge.net. 14      IN      A

;; Query time: 0 msec
;; SERVER: 2001:980:14ca:42::18#53(2001:980:14ca:42::18)
;; WHEN: Wed Feb 25 20:20:34 2015
;; MSG SIZE  rcvd: 244
Online there are some similar messages: Smart TV mayhem for Sony and Samsung users after central servers go down, Internet-Ausfall bei Samsung Smart-TV

According to some reports the fix is simple: Users fix Samsung Smart TV down time themselves – Two workarounds known which both hardcode an Akamai IP for www.samsung.com and skip the CNAME chain. Remember when DNS manuals told you CNAME chains were a bad idea? They still are, I guess. I implemented the fix locally with pdns-recursor and the export-etc-hosts option which allows me to serve an A record for www.samsung.com (the IP I get from the CNAME chain). And indeed, the smart TV applications work again.
Read the rest of Samsung TV decides the Internet is broken

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2015-02-24 More work on getting asterisk to work as an ISDN network terminator on the test server 3 days ago
I dug up all the tools needed to test the isdn setup in the test server: an old sitecom ISDN card with HFC-S chipset, an ISDN cross cable, a fritzbox with external S0 bus and an analog phone set.

It took me a while to get all 3 channels in the ISDN card active in Asterisk, I 'missed' the fact that the oslec echo canceller wasn't loaded due to a module versioning problem. At first it showed:
root@metcalfe:~# lsdahdi
### Span  1: DAHDI_DUMMY/1 "DAHDI_DUMMY/1 (source: HRtimer) 1" (MASTER)
### Span  2: ZTHFC1 "HFC-S PCI A ISDN card 0 [NT] " AMI/CCS
  1 BRI        Clear       (In use)
  2 BRI
  3 BRI
The switch from oslec to mg2 fixed things:
root@metcalfe:~# lsdahdi
### Span  1: ZTHFC1 "HFC-S PCI A ISDN card 0 [NT] " AMI/CCS
  1 BRI        Clear       (In use) (EC: MG2 - INACTIVE)
  2 BRI        Clear       (In use) (EC: MG2 - INACTIVE)
  3 BRI        Hardware-assisted HDLC  (In use)
### Span  2: DAHDI_DUMMY/1 "DAHDI_DUMMY/1 (source: HRtimer) 1" (MASTER)
But whatever I tried: no dialtone. Time to also hook up a SIP phone to initiate calls the other way.
Read the rest of More work on getting asterisk to work as an ISDN network terminator on the test server

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2015-02-23 Preparing for upgrades and testing speed improvements for my homepage 4 days ago
As part of a needed upgrade on my homeserver I will also have to deal with Apache 2.4 and the changes needed there. Because some other things will change completely like asterisk I used an old server with comparable packages to do the same upgrades and test the results.

As keen visitors to my page may have noticed I am interested in the performance. This test-setup also gives me room to experiment with some possible new methods. I have to establish a baseline on that server first since it has different hardware.
Read the rest of Preparing for upgrades and testing speed improvements for my homepage

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2015-02-22 Another weekend, another digimode contest... 5 days ago
Some radio amateurs complain that there seems to be a contest every weekend. And they may have a point: yesterday I found the digimode users 'all' busy with the Russian WW PSK contest so I checked the website, adjusted the macros and joined the fun. Other activities at home also had to be done but I managed to make a total of 38 contacts on the 10 and 20 meter bands during this contest. Given the fact that I made a number of contacts on both bands I entered my log in the single-operator multi-band category.

I saw nobody from the US in this contest, mostly Russian, Eastern European and a few Dutch callsigns. Given the high serial numbers I saw fly by I will not be a winner of anything, but it was nice to participate.
Read the rest of Another weekend, another digimode contest...

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2015-02-18 Old-skool usernames in ssh attacks 1 week ago
Somebody dug up some 'hacking VMS' howto files I guess:
Feb 17 21:53:25 greenblatt sshd[8483]: Invalid user OPERATOR from
Feb 17 22:00:43 greenblatt sshd[9138]: Invalid user RSBCMON from
Feb 17 22:09:54 greenblatt sshd[9962]: Invalid user FIELD from
Feb 17 22:18:39 greenblatt sshd[10837]: Invalid user MANAGER from
Feb 17 22:35:21 greenblatt sshd[12290]: Invalid user SYSDBA from
Some of the old 'default accounts' from way back! HACKING VAX'S VMS. at textfiles.com

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2015-02-16 Bits from the radio, receiving Radio Data System 1 week ago
I had to have a look at Receiving RDS with the RTL-SDR - Absorptions and indeed it works. Tuning to NPO 3FM:
8203  0A TP:0 PTY:10 TA:1 MS:M AF:89.9MHz AF:90.9MHz PS:'NPO 3FM '
8203  0A TP:0 PTY:10 TA:1 MS:M AF:96.2MHz AF:96.5MHz PS:'NPO 3FM '
8203  2A TP:0 PTY:10 RT:'BNN: Dit is Domien↵                                             ' RT_OK
8203 14A TP:0 PTY:10 ON:8204[TP:0 PS:'NPO     ']
8203 14A TP:0 PTY:10 ON:8204[TP:0 PS:'NPO     ']
Found via Receiving RDS with RTL-SDR - Software radio on Google+

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2015-02-16 Non-unique RFID Unique numbers 1 week ago
I recently learned that more than one Android mobile phone with NFC support has the same Unique ID: 01020304 (hex). If you want to use RFID tokens for authentication for certain tasks and let users bring their own tokens you need to block this specific not so unique ID.

Together with the fact that there are cards on the market where you can change the UID this means depending on an RFID UID only for authentication needs a serious risk assessment. But gaining access to more information on an ISO/IEC 14443 RFID device means that you either have to set the rules for the card (and probably pay for it) or make a rule for every type of card you find and still have issues.

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2015-02-15 I played in the CQ WPX RTTY contest 1 week ago
Sunday I noticed a distinct lack of replies to my calls in PSK31 mode on the standard places in the 10 and 20 meter amateur bands. So I spun the dial and noticed a lot of RTTY traffic. This turned out to be the CQ WPX RTTY contest. So I answered a number of CQ TEST calls and exchanged the stunning number of 13 QSOs.

The fun part is that this is a way to make contacts in new places. Normally I don't get through to the US or Canada easily but now I made several contacts there. And I had contacts in Cyprus and Aruba. Now to see which ones I can get confirmed.

One new and puzzling thing to me was receiving EYR as a serial. This confused me but the other side was quite convinced it was a valid serial. But the logrobot for the contest did not accept it so I googled and found out in RTTY numbers can be written as letters. The simple way is to look at a US keyboard for transposing: 1=Q, 2=W, 3=E, 4=R, 5=T, 6=Y, 7=U, 8=I, 9=O, 0=P. So EYR translates to 364.

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2015-02-14 Another RS0ISS slow-scan TV opportunity 1 week ago
Another chance to receive slow-scan TV images from the Russian crew on board of the ISS (callsign RS0ISS): they will transmit SSTV images in the weekend of 21-23 february. According to the announcement More ISS Slow Scan TV Activity - Amsat-UK the images will be from the set of 12 pictures celebrating space pioneer Yuri Gagarin.

Update 2015-02-20: It seems this event may be postponed: extra vehicular activities (spacewalks) have been scheduled for this weekend and amateur radio transmissions are completely shutdown when persons are outside.

2015-02-13 (Het is 2015 en e-mail bij UPC is niet via versleutelde protocollen te bereiken. In de uitleg op http...) 2 weeks ago
Google+Koos van den Hout : Het is 2015 en e-mail bij UPC is niet via versleutelde protocollen te bereiken.
In de uitleg op http://www.upc.nl/klantenservice/internet/e-mail-instellen-mozilla-thunderbird/ staat dat de gebruiker de waarschuwing over onveilige instellingen moet accepteren zonder verdere uitleg.
#encryptie #onlineveiligheid
Ik ben blij dat ik daar geen account heb.
2015-02-11 Exit Ziggo, of beter: exit overbodige televisiekanalen 2 weeks ago
We realiseerden ons al een tijdje dat we tegenwoordig op de TV voornamenlijk uitzending gemist, Netflix, mediaspeler en NPO 1/2/3 kijken. Toen Ziggo dan ook recent kwam met een kleine prijsverhoging met de mogelijkheid om direct op te zeggen was de keuze wel duidelijk. Deze week moest ook nog eens het hele aanbod op de DVB-C ontvanger opnieuw ingeladen worden vanwege de veranderingen in het Ziggo netwerk dus we hebben dat moment gepakt om een simpel UHF sprietje in de TV te steken en die een DVB-T service scan te laten doen. Prima ontvangst van NPO 1/2/3. Dat is een voordeel van zo dicht bij diverse DVB-T zenders wonen.

Opzeggen bij Ziggo kan alleen telefonisch maar de wachttijd viel enorm mee en de prijsverhoging noemen gaf vlotte afhandeling van de opzegging.

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2015-02-05 (Enjoyed the episode!) 3 weeks ago
Google+Koos van den Hout : Enjoyed the episode!
2015-02-01 (My reception of the RS0ISS SSTV image number 11 from the set. Not everything went as planned and I need...) 3 weeks ago
Google+Koos van den Hout : My reception of the RS0ISS SSTV image number 11 from the set.
Not everything went as planned and I need to calibrate the sstv software.
But.. I have an image received from the ISS!
2015-01-31 Received an image from ISS 3 weeks ago
Image received from ISS SSTV callsign RS0ISS
Image received from ISS slow scan tv at location JO22NC 2015-01-31 starting 20:47
This chance of receiving images from ISS I took it and tried to recieve one. Not everything worked as planned: recording the audio while receiving the image with qsstv failed, someone tried to transmit on the downlink frequency to contact the ISS and the image is slanted which probably means I need to calibrate qsstv and/or the soundcard.

But, it worked! An image from the international space station!
Read the rest of Received an image from ISS

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2015-01-31 World news in my amateur radio contacts 3 weeks ago
And sometimes world news gets into my amateur radio contacts, even when both sides don't really want that:
Pse QSL via LoTW,eQSLc .. please no bureau now. War here
This was in a contact with a radio amateur operator in the Donetsk region in Ukraine.

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2015-01-31 Interesting interference in the 10 meter amateur band 3 weeks ago
waterfall plot of interference I had the radio and computer running checking for PSK31 signals at 28.120 MHz, the standard frequency for PSK31 in the 10 meter band. Suddenly I saw lots of carriers 5 Hz apart and very precise. I checked the websdr in twente and saw the same signal.

So I tried to make a screengrab of it and it went away. To show up at 27.120 MHz exactly the same and annoying some 27 MHz CB users.

I'm not sure what it was, my first guess was over the horizon radar which is 'famous' for interfering on HF amateur bands. Moving 1 MHz down when the HF propagation maximum frequency is dropping is also a sign of something like over the horizon radar.

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The person

Father, cat owned/owner, Unix/Linux fan, Internet user, reader, recumbent byciclist, snowboarder, ipv6 fan. For those who don't speak Dutch: how to pronounce Koos van den Hout.

The job

Specialist information security at Utrecht University with a modern Profile page.

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Meningen zijn die van mezelf, wat ik schrijf is beschermd door auteursrecht. Sommige publicaties bevatten een expliciete vermelding dat ze ongevraagd gedeeld mogen worden.
My opinions are my own, what I write is protected by copyrights. Some publications contain an explicit license statement which allows sharing without asking permission.
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