Interpreting File Explorer GPS Coordinates

Do you notice something wrong with coordinates of this picture taken in Pasco, Washington?

Let’s disregard for moment a pointless precision. Four decimals on Lat/Lon seconds already bring you into a millimeter precision range. With 15 decimals Windows show we are talking about less than picometer - couple orders of magnitude smaller than a virus and more than adequate to locate a single DNA strand (still in nanometer range).

Anything over 2 decimals on seconds (or 6 decimals on degrees) is already way better than any standard GPS can resolve. If we are talking about specialized equipment, we can probably justify 5 decimal digits. Going to 15 digits is just a sign of programmer too lazy to round.

Let’s not even discuss that semicolon is used instead of proper signs for decimal degrees. Yes, latitude should be written as 46° 15′ 12.51″ instead but that is not the biggest fault.

Did you notice it yet? Yep, latitude has no north/south specifier nor is east/west shown for longitude. Alternative approach of having negative numbers instead of south and west is also not here. How do I know? Because this picture has been taken in North America and not in China.

Positive latitude is correct since picture was taken in the north hemisphere. However, longitude is very wrong as degrees number should have a negative prefix for west hemisphere where picture was taken.

In any case, I made a little calculator to convert Microsoft’s coordinates into standard ones:

Disabling SSH Password Prompt

After cancelling my hosting, I noticed my e-mail reports stopped working. Since I also upgraded my server with a troublesome version, I originally didn’t connect those two. However, issue with reports persisted even after I fixed the e-mail issue.

Manually running report immediately identified the problem. You see, I login to every server using public key. As my login on DreamHost server was gone, SSH simply decided to fallback to keyboard authentication. And so report waited for keyboard input that was never to come.

Solution intended for this troublesome issue actually already exists in the form of BatchMode option. Appending -o BatchMode=yes to SSH command will cause it to rather fail than ask user for anything. Exactly what doctor prescribed for my report script.

With this update, my “standard” SSH crypto settings for the report got updated to:

ssh
  -2
  -o KexAlgorithms=diffie-hellman-group-exchange-sha256
  -c aes192-ctr
  -o MACs=hmac-sha2-256
  -o BatchMode=yes
  example.com

TP-Link's Idea of Security

My wired network finally got too big for a single router so I decided to get myself a switch.

I realistically needed the dumbest switch there is - just 4 gigabit ports and I would be happy. Thus my eyes were immediately drawn to TP-Link SG105 at $20 on Amazon. However, for only $10 more I noted one could get SG105E. The exactly same switch but with a basic manageability features.

Both switches look exactly the same in their steel shell. They are well built and my impression is they can take a beating. You can get inside the chassis by simply undoing two screws and you will see a really simple board. Based on the components, I don’t think you can get much over 1 Gbps on its bus and thus forget about actually reaching maximum speed when all ports are in use - acceptable compromise for home I guess. I would say 9V power supply is the only thing that actually looks cheap. Fortunately, switch works without any noticeable issues on much more common 12V too (albeit you probably forfeit warranty if you do that).

So, what do you get for extra money? Well, you get DSCP, a QoS priority system nobody seems to use in general and definitely not intended for home network. There is also rate limiting with a storm control. Probably not often needed at home but can be quite useful for troubleshooting naughty device.

Further more you get support for up to 32 VLANs - quite nice if your home network needs a bit of separation. Lastly you will also find more “enterprisey” features like port mirroring and link aggregation. Never figured why you need something like this on 5-port switch but I guess it doesn’t hurt to have them.

The most useful feature, and the reason I decided to give extra tenner was the GUI. From GUI you can easily see if your cable is connected, whether packets are flowing, and are there any transmission errors. Usually home switches and routers have ugly interface so I was ready for that. What I wasn’t ready for is abysmal security.

Let’s start with a good thing - you can change user name. Security-wise, that is probably the best thing you can do in your network to escape 95% automated attacks. Yes, this won’t help much if someone is “out to get you” but most script kiddies will be thwarted. And that’s as far as security goes for this device.

To start with, your password is restricted to English alphabet, digits, and underscore (_) sign. Restricting the length and character set is not significant just because it lowers number of combinations your password can take. I am sure you are using password manager and even these weak rules should give you years of good sleep if password is hashed.

But, if they used hashed passwords in the first place, they wouldn’t need character set restrictions. These restrictions are almost always a signal your password is saved in a clear-text. Combined with the login screen allowing for infinite number of guesses at unthrottled speed, and you have the whole security tumbling down.

But don’t worry anybody will brute force this device. Nope - there is no need as you can simply snoop all communication as there is no support for HTTPS. Everything you do on its web interface is for everybody to see. They didn’t even bother to do a simple digest authentication. Nope, all is sent in clear text.

For $20 it is hard not to recommend base model of this switch. It is sturdy, cheap, and reasonably performant. Unfortunately, for only $10 more you can get a device performing the same base function but with a woefully insecure user interface.

I would stick with unmanaged model.

NAS4Free Serial Console on Supermicro A1SRi

Having Supermicro A1SRi motherboard is awesome - especially when it comes to remote management over IPMI. However, as I have NAS4Free on it, one thing annoyed me all the time - why I don’t see anything in IPMI Text Console tab? It’s not that I really need it as iKVM works for me, but I find inactive things annoying. So I went to correct this grave omission.

Albeit it took me a while to configure it, the final setup is easy. Utter lack of documentation is what caused the drag.

First step is to enable console redirection in Supermicro’s BIOS. While COM1 is best left to the BIOS itself, COM2/SOL is ours for taking. The only thing needed is to enable second serial console.

For the next (and final) step we must visit NAS4Free’s GUI under System, Advanced, loader.conf in order to setup four variables controlling the boot process:

Using boot_multicons essentially tells FreeBSD to allow boot output to multiple consoles. Without this, only one console would be supported for boot messages.

That is crucial for the next console variable where we set console output to both video console (vidconsole) and to serial console (comconsole). And the order is important. While most messages will be mirrored on both outputs, some “userland” (e.g., application, rc.d, and script) messages will be displayed only on the first. I personally like to have that on the video console as it allows for color and looks nicer but your mileage (and needs) might vary.

Last two settings control which address the port is located at (COM2 is traditionally at 0x2F8) and the serial port speed has to match Supermicro’s default of 115200 bauds.

PS: Yes, these steps work on FreeNAS too.

[2018-07-22: NAS4Free has been renamed to XigmaNAS as of July 2018]

About Time

As we approach yet another biyearly daylight savings time change, there came a news about politicians actually doing something smart for a change. European Parliament voted to keep the same UTC offset the whole year round. If this decision is followed through, gone are the days of hunt for every clock to update it an hour back or forward before the next change comes.

And yes, of course it is not as simple as turning the daylight change off. First it needs to get to the European Commission that traditionally likes to avoid implementing anything. Then all member states need to agree when to do it. Then decision needs to be postponed multiple times. Then everybody will try to implement the decision at the very last moment. You know, the usual.

However, for the first time in forever there is some hope. I can already see myself talking to my grandchildren about the dark times when people all around the world changed their time by hour (or less - damn you Lord Howe Island), for reasons long forgotten, and at the time every country decided upon themselves.

Grandchildren will probably just say that grandpa is crazy and that this could have never been. And then they will go out to play in the UTC world…