Posted in Me

Fixing Ubuntu 17.04 DNS problems

I recently upgraded my Ubuntu box to 17.04.

Much to my surprise DNS starting behaving strangely, so I checked my DNS server … worked fine if I queried it directly, so I checked if DHCP was giving out the wrong DNS IP … nope, that was fine too. I checked /etc/nsswitch.conf , and that looked fine too so I checked what was ending up in /etc/resolv.conf and was surprised that it contains nameserver  instead of the “real” DNS server.

After a bit of research I found out that Ubuntu switched over to using systemd-resolved, which shoves itself between user land and the DNS servers and (at least in Ubuntu 17.04) has problems with servers that support DNSSEC. Very frustrating when you know everything is OK and worked in the past, just systemd messing with stuff and breaking it.

My workaround was to turn of DNSSEC validation. Not pretty but better than no DNS at all, until Ubuntu get’s their problems sorted out.


Posted in Me, Tech

A script to diff files/directories on two different servers

Ok,  short one today. This is a straightforward script that simplifies comparing directories on different servers. There is no magic in it, it just rsyncs the directories to a local temp directory and runs diff against them (then deletes the directory afterwards). Mainly intended for config files, I wouldn’t recommend trying to diff gigabytes of binaries with it.


Posted in Photography

Picture galleries from last fall

This weekend I finally got around to uploading some pictures from our trip last fall to the Grand Canyon, Las Vegas (no pics), Death Valley, and Sequoia & Kings Canyon National Parks.
The cave pictures at sequoia national park are from crystal cave.

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Posted in Photography

Picture galleries from trips this summer

Since we are going on a small vacation tomorrow I wanted to get a couple picture galleries up before I start filling my drive up with new pictures. These are all from small trips/excursions we took over the summer. Unfortunately no pictures from the canoe on the st. croix river.

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Posted in Me – catching data leaks

I was testing a PHP script for security flaws today and needed a way to check if it was possible to “accidently” leak sensitive data to an external server. So I threw together a small script to save the contents of the $_SERVER $_COOKIE $POST and $_GET arrays and dump them in a file. Since it worked so good I decided to leave the site online.

Why did I call it silica? Because silica gel absorbs and stores fluids like this website absorbs information thrown at it. How to use it? Just get your application to connect to instead of where it intended to connect to (by overwriting variables, DNS foo, be creative) and see what happens.

Base Domain:
The webserver will catch any URL (regardless what path or filename) and log the environment. The only exception is the logfile.

The log is automatically emptied every 10 minutes, so save the output if you need it.

Posted in Me

How to use Cluster SSH (cssh) and Mosh together

A colleague told me about mosh today, just saying “it’s an alternative to SSH that addresses many of the problems” doesn’t do it credit. Go look at the page and have a look, don’t worry it’s a nice page and I’ll still be here waiting when you come back. I do a lot of work on servers across the globe, and believe me, although subtle, the difference between a 10ms connection and a 100+ ms connection is definitely noticeable 😉 That lag all but disappears with mosh. Mosh doesn’t support X11/SSH-Agent forwarding yet, but it’s on their roadmap.

Back to topic, I also use cssh for working on multiple servers simultaneously. I’d recommend making a copy of your .cshrc file (cp -a ~/.csshrc ~/.csshrc_mosh) and working on the copy. Edit the  ~/.csshrc_mosh and change the lines ssh= and ssh_args= (diff of my files):

You will have to remove any parameters in ssh_args= and move them to your ~/.ssh/config due to the difference in command line parameters between mosh and ssh. Now all you have to do is call cssh with the new config file, e.g. with an alias to make things easier alias mcssh=”cssh -C ${HOME}/.csshrc_mosh” And your done.

Posted in Gaming

Floor plans for PAYDAY Map “Diamond Heist”

I’ve played PAYDAY the last few weeks, it is a 4 player CO-OP FPS (think of Left 4 Dead in a different setting). One of the maps has caused me a bit of difficulty (Diamond Heist). There is an achievement called “Are Those The Blue Ones?” where you have to collect all the sapphires before the alarm goes off, and I kept forgetting where they were. Also keeping track of the cameras was a bit of a pain, so today I threw them all together on a map for easier reference (right-click “Save link as …” to download):

Graphics sources:–diamond-by-lmproulx

Posted in Me

Playing around with DD-WRT

I’m currently playing around with my two WL-330GE Access points from asus (see an older posting). Since that posting I was a bit creative using the existing ethernet cabling and ports in the apartment to be able to retire the WiFi bridge without having any cable going through the apartment.

So I decided to use the two access points for something more useful. I’m playing around with dd-wrt to build configurations to use them as WiFi probes (for an IDS), or as Rouge Access Points (for demonstration purposes and to test wireless IDS solutions).  I might compile my own dd-wrt version for the rouge version, there are a few things I miss to build a truly evil device.

I like the size of the devices (very compact) and that you can power them with 5V (you can run them off any USB port, right now the one here is hooked up to the USB port of a printer intended for cameras) the only thing missing to make them perfect would be Power-over-Ethernet and maybe a GSM interface to upload data online.

Fun having a cheap and small device like this with Wifi and ethernet running linux. Provides lots of possibilities and fun.


Posted in Me, Photography

How to make a wonderful cookie dessert in a skillet

A few weeks ago I stumbled across this recipe for making a cookie in a skillet and shared it with a few people because I though it looked cool. My wonderful wife then put “skillet” on our shopping list because she knows I can’t resist cookies, and yesterday we tried out the recipe. It was easy and tasted wonderful 🙂

Below are some pics of the treat.

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Posted in Gaming, Programming

How to increase Fraps performance with a ramdisk

I recently started playing Battlefield 3 and remembered that I have a Fraps license so I installed it and started recording some stuff. Unsurprisingly the performance made a big dip when I recorded. A glance at my PC told me the harddrive was at fault, probably bringing the whole system down due to IO.

Since my PC has more than enough RAM I decided to set up a 5Gb Ramdisk to see if that helped. It did, when writing the video files to the ramdisk I hardly had any performance hit. Unfortunately 5GB isn’t going to last long while recording 1920×1080 @ 40FPS (a few minutes footage at most).

Here is my little cmd file to create a 5GB ramdisk as drive J: and format it for usage:

So my next thought was to see if I could write a script to move files off the ramdisk when they were done being written to by Fraps. This obviously was going to cause IO load … the reason we were having performance issues in the first place, so I was skeptical about if this was going to help any. Especially since I also had to move the files away quick enough so that the drive wouldn’t fill up completely with the next file Fraps was writing. I wrote a little powershell script for this (yeah, a *nix Sysadmin writing scripts in powershell …)

Here is my little powershell script to copy the finished files from my ramdisk to a normal HDD (please excuse  possible ugliness, I’m a powershell noob):

The last little problem I noticed is that the 5GB ramdrive wasn’t big enough (Fraps seems to create some dummy files and fills them up). Forcing Fraps to make smaller files by toggeling the recording fixed that though -> pressing F9 twice fast will drop a few frames though. I used my Logitech G13 for that, just had a key mapped to press F9 quickly every 60 seconds. The shortest gap I could get working reliably is 50ms.

This all probably sounds awfully complicated, but it works and solves my problem. Fraps is great software, but it would be immensly helpful if you could set the file size in the settings (instead of it defaulting to 4GB). Or, even better, if Fraps could rework their IO system to work more efficiently.

So to sum everything up:
– create ramdrive
– start script that copies files from the ramdrive to a normal HDD
– set fraps to store videos on the ramdrive
– start game, press F9 to start recording and then press the G13 key to toggle the F9 periodically

Posted in Me, Photography

Yellowstone and Grand Teton Parks

A few weeks ago we traveled a bit west and visited the Yellowstone and Grand Teton National Parks, I’ve finally gotten around to sorting through the pictures and uploading a few (well, actually a lot).

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I didn’t get around to editing and stitching the panorama photos together yet, or doing anything interesting with the GPS data of our hikes yet. If I get that done I’ll probably update this posting.

Posted in Me

rcon.c sorcecode (for linux)

Searching for a linux command line rcon tool can be a bit of a pain: dead links, outdated versions not working anymore, stuff written in php …. yeah. The only version I could find was stuck in a cache of an old webpage. So here is my mirror of the file that currently gives you a “404, File not found” error. Hopefully this will help anyone trying to find a working version via google and is frustrated with the results. Download, compile, happiness ensured.

Posted in Me, Tech

win7 system restore … aaarrrrgggh

Warning: this is mainly me just ranting about Microsoft stupidity and a warning for anyone using junctions.

About a month or two ago I built myself a new PC (old one was dying) and installed Win7 on it.  Since I was previously still on WinXP there were a few things to get used to, but all in all I enjoyed the update. There were of course some strange Windows pitfalls involved, moving your users directory to a different drive really isn’t straightforward, but works if you use junctions to link the directories.

Since Virtualbox drops the guests in a subfolder of the users directory I decided to move my users directory to one of the larger mechanical disks in my system, to keep the windows drive (a SSD disk) with plenty of space.

Now fast forward to yesterday, where some software I installed decided to clear out most of my Start->All Programs folder, leaving me with lots of installed softawre, and no Start Menu links. After trying some stuff out I finally caved in and used System Restore to get my Start Menu working again. System Restore actually worked fine, I got my Start Menu back … unfortunately it also corrupted my profile, and while googling to find out how to fix it I found a whole lot of people with the same problem.

Junction + User directory + System Restore = corrupt user, non repairable. Hello Microsoft, this is all original system software, no 3rd party stuff, breaking my user is totally uncool.

So after trying all kinds of crazy tips I found I gave up and followed the official instructions (a.k.a. You are fucked, haha bye bye user registry). And right now I am copying stuff from my old profile to my new one and setting up all the software that had stored stuff in the registry. This time my Profile stays on C: without any junctions, it’s easier to repair Virtualbox if it breaks over the images being in a non-standard path than worrying about windows corrupting my whole profile if I touch System Restore.

Posted in Me

Where to find real bread in Twin Cities

Anyone from Europe will tell you that what Americans generally consider “bread” is more like a loaf of bland nothingness with the consistency of a sponge that can be mushed together into something resembling playdough. To be fair, it is okay if you get some multigrain bread and toast it to give it some firmness and make sandwiches, but other than that ….

Artisan bread is a step up and brings a bit more taste and firmness. It can be found at various stores, we generally get some from Cub or Trader Joes. But the best bread we have found till now is at a local  “breadsmith” here in Minneapolis / St. Paul. They truely sell real bread. Yaaaay. So if there is a breadsmith near you, drop in and have a look, might be you find bread like you have never tasted before.

Posted in Gaming

Thanks for the free games @Valve

For the release of their latest game Portal 2, Valve went to great lengths marketing wise. They set up an “Alternate reality game” (ARG) with tips and puzzles hidden in 13 independent games (to promote indie games). Some of the games even added extra levels just for the ARG.  Solving puzzles, finding passwords, and triggering special events led to the possibility to gain “potatoes” as a sign of progress. If all 36 potatoes were found in the 13 games involved players got a golden potato.

After the ARG was solved by the community, Valve added a countdown a few days before the release of Portal 2, allowing the community to get Portal2 to release early by collecting potatoes and (in the end phase) playing the 13 indie games.

Last Friday Valve announced in the official blog “There’s also still time to collect all 36 potatoes. Anyone accomplishing this feat by the time Portal 2 launches will receive a very special, non-hat-based reward.” An extra incentive for people to play the games involved and collect the potatoes. I spent most of the last days collecting all 36 potatoes, got the last one just hours before the deadline.

Today everyone with a golden potato  got the reward, a valve complete pack and a copy of portal2. I’m honestly impressed. I never would have expected them to not only give out all their previous games ($100), but also a free copy of their latest game they just released yesterday ($50).

Impressive move Valve, even if I was irritated at buying the game on steam on pre-order and then seeing Amazon and Best Buy drop the price shortly before release by 10$, the ARG and the potatoes blew everything out of the water. So now I have a few copies of games I already owned to give out 🙂

Posted in Me

Moving to the USA

I haven’t posted here for a while. One of the reasons is that I started posting more day-to-day stuff on facebook, but the main reason was that the last few months my wife and I have been busy organizing stuff. She got a job offer over here, so December and January we were busy getting everything organized to move from Germany to USA. In December we flew over for a week to get an apartment rented, buy a car, set up a bank account, insurance, … all the fun stuff you go through when moving to a new place. Let it be said, that christmas time is not the advised time to organize such stuff :-p
Steffi flew in on the 15th, and I came over a week later. And now our new home is in (the cold) Twin Cities 🙂 Our internet conenction isn’t going to be installed till Feb 1st (along with phone and TV), so I don’t have much to do except for cleaning the appartment, assembling furniture (IKEA is just around the corner) and shopping … and of course keeping an eye out for interresting jobs here. I’ll keep you all posted on how things are going here, If the sun ever comes out I’ll go out to shoot some photos.