The Daily WTF: Curious Perversions in Information Technology

alegr · 2014-04-22 Reply Admin

dkf:
vt_mruhlin:
We don't have problems with users of electricity running an extension cord between two outlets, do we? Because they can't
You know why they can't? Because electricians make sure they can't. And yet such abominations still happen; never underestimate the power of ignorance coupled to determination...

Ever seen generators with a plug?

2014-04-22 Reply Admin

/me mumbles something about spanning tree

2014-04-22 Reply Admin

anon:
faoileag:
vt_mruhlin:
As I read the thread, it occurs to me that the real WTF is the connector design on network cables. The plug is shaped the same way on both ends, reinforcing this kind of behavior among users.
We don't have problems with users of electricity running an extension cord between two outlets, do we? Because they can't
Perhaps because then you would also need two kinds of sockets on the switches?

Just design a cord with a different plug in each end and a socket that can accomodate both. Problem solved.

You're getting dangerously close to re-inventing those horrible Token Ring connectors.

dkf · 2014-04-22 Reply Admin

alegr:
Ever seen generators with a plug?

Ever seen what a determined user can do?

2014-04-22 Reply Admin

I have a female to female 240V extension cord. How better to connect the generator to the house wiring when the power goes out???

2014-04-22 Reply Admin

Skunk:
I have a female to female 240V extension cord. How better to connect the generator to the house wiring when the power goes out???

Sorry, make that male to male!!!

snoofle · 2014-04-22 Reply Admin

Skunk:
Skunk:
I have a female to female 240V extension cord. How better to connect the generator to the house wiring when the power goes out???

Sorry, make that male to male!!!

how do you keep the power from going the wrong way down the power line where utility workers might be touching what they think are dead wires? I'm assuming your extension cord doesn't have a built in transfer switch...

2014-04-22 Reply Admin

I would seriously recommend you not to do that. You may end up killing or injuring the worker at the power company by sending power back over the power circuit that's supposed to be dead.

If you really have to, make absolutely certain that the main breakers are turned off before you plug that generator in. Even that might not be enough if the breakers don't interrupt all poles (depending on the electrical code in your country).

And of course, you have to take care of not unplugging the wrong end of the cable ending up with AC voltage on exposed pins.

Disclaimer: I am not an electrician but I know enough to not mess with this kind of stuff.

2014-04-22 Reply Admin

I guess the real WTF is using cheap unmanaged switches on a large network. If you decide to go ahead and do so anyway then a loop and corresponding broadcast storm is almost inevitable. Heck even on a small home network it's easy to plug in the wrong cable somewhere.

But to do it right takes money and experiance, it sounds like both of those were in short supply.

Matt Westwood · 2014-04-22 Reply Admin

pv2b:
I would seriously recommend you not to do that. You may end up killing or injuring the worker at the power company by sending power back over the power circuit that's supposed to be dead.
If you really have to, make absolutely certain that the main breakers are turned off before you plug that generator in. Even that might not be enough if the breakers don't interrupt all poles (depending on the electrical code in your country).

And of course, you have to take care of not unplugging the wrong end of the cable ending up with AC voltage on exposed pins.

Disclaimer: I am not an electrician but I know enough to not mess with this kind of stuff.

The real WTF is thinking that the suggestion about the generator and the house power supply was a serious suggestion, yeah?

2014-04-22 Reply Admin

Kristof Provost:
I think that I shall never see A graph more lovely than a tree. A tree whose crucial property Is loop-free connectivity. A tree that must be sure to span So packets can reach every LAN. First, the root must be selected. By ID, it is elected. Least-cost paths from root are traced. In the tree, these paths are placed. A mesh is made by folks like me, Then bridges find a spanning tree. -- Radia Perlman

Feature this! Pretty Please?

chubertdev · 2014-04-22 Reply Admin

Matt Westwood:
The real WTF is thinking that the suggestion about the generator and the house power supply was a serious suggestion, yeah?

Maybe he has a diode the size of a Volkswagen.

2014-04-22 Reply Admin

In my years as a school computer technician I couldn't tell you how many loops I've tracked down. Students know they can bring down the network and do it to screw around.

2014-04-22 Reply Admin

Carpet cleaning once led to just that. We were less lucky, the entire network including external websites went down hard.

2014-04-23 Reply Admin

Matt Westwood:

pv2b:
I would seriously recommend you not to do that. You may end up killing or injuring the worker at the power company by sending power back over the power circuit that's supposed to be dead.
If you really have to, make absolutely certain that the main breakers are turned off before you plug that generator in. Even that might not be enough if the breakers don't interrupt all poles (depending on the electrical code in your country).

And of course, you have to take care of not unplugging the wrong end of the cable ending up with AC voltage on exposed pins.

Disclaimer: I am not an electrician but I know enough to not mess with this kind of stuff.

The real WTF is thinking that the suggestion about the generator and the house power supply was a serious suggestion, yeah?

Unfortunately, people have actually used such things. Not only is it very real danger to linemen, that kind of AC extension cable, with two male ends, is called a "suicide cord" for a reason. Don't underestimate stupid.

2014-04-23 Reply Admin

This was actually a common prank pulled by disgruntled/trolling students who had finished IT school. Aparently the IT staff never figured out how to stop this sort of thing.

2014-04-23 Reply Admin

Definitely seen this before in a prod environment. Someone in the IT dept had an unmanaged switch on his desk and plugged both ends in.

We quickly found out that day that both the 128-port HP procurve core switches for our 150+ person office did not have spanning tree enabled.

Man was that one fun to track down.

2014-04-23 Reply Admin

snoofle:
Skunk:
Skunk:
I have a female to female 240V extension cord. How better to connect the generator to the house wiring when the power goes out???

Sorry, make that male to male!!!
how do you keep the power from going the wrong way down the power line where utility workers might be touching what they think are dead wires? I'm assuming your extension cord doesn't have a built in transfer switch...

What electricians do you know just assume any odd cable is dead.

Assume live.

You don't pick up a gun, point it at your head and pull the trigger to test if it is loaded?

Don't pick up a power line without checking it for load, and never assume it can't suddenly have load.

2014-04-23 Reply Admin

An electrician who turns off the (upstream) breaker and then checks the line before working on it does. He doesn't suddenly expect power from downstream to start surging through his veins...

snoofle · 2014-04-23 Reply Admin

Matt Westwood:
pv2b:
I would seriously recommend you not to do that. You may end up killing or injuring the worker at the power company by sending power back over the power circuit that's supposed to be dead.
If you really have to, make absolutely certain that the main breakers are turned off before you plug that generator in. Even that might not be enough if the breakers don't interrupt all poles (depending on the electrical code in your country).

And of course, you have to take care of not unplugging the wrong end of the cable ending up with AC voltage on exposed pins.

Disclaimer: I am not an electrician but I know enough to not mess with this kind of stuff.

The real WTF is thinking that the suggestion about the generator and the house power supply was a serious suggestion, yeah?

Sadly, idiots do it all the time - after hurricane Sandy, someone did it (near where I live) and zapped an electrician who was trying to restore power. They rushed him to the hospital, and we took an extra two days to get someone else to fix it.

2014-04-23 Reply Admin

What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?

chubertdev · 2014-04-23 Reply Admin

Jon:
What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?

I wouldn't think so. Similar to how you treat a gun as if it's always loaded.

2014-04-23 Reply Admin

Valued Service:
snoofle:
Skunk:
Skunk:
I have a female to female 240V extension cord. How better to connect the generator to the house wiring when the power goes out???

Sorry, make that male to male!!!
how do you keep the power from going the wrong way down the power line where utility workers might be touching what they think are dead wires? I'm assuming your extension cord doesn't have a built in transfer switch...

What electricians do you know just assume any odd cable is dead.

Those who want to join the cables?

2014-04-23 Reply Admin

Happens all the time in our training rooms. One thing we strive to teach them is "Don't Do That!!!"

(And when they do, we quickly isolate that segment and send someone to unplug the loop.)

2014-04-23 Reply Admin

vt_mruhlin:
As I read the thread, it occurs to me that the real WTF is the connector design on network cables. The plug is shaped the same way on both ends, reinforcing this kind of behavior among users.
We don't have problems with users of electricity running an extension cord between two outlets, do we? Because they can't

We used to have straight and crossover wiring configuration for LAN cables. One for connecting machine to network, the other for machine to machine.

Just that modern networking equipments can automatically detect them and make them both works, so the difference become non-existent.

2014-04-24 Reply Admin

The switches are working the way they are designed to, flood packets out all ports except the originating port. If there's a redundant link in a loop, you get broadcast loops and it'll take down the switch/network.

That's why Spanning Tree was invented, but these are unmanaged switches.

I don't really see this as a WTF, since it is pretty common in networks with unmanaged switches; which is why companies that get bigger than a few people typically buy managed switches.

In this case, it seems like a pretty simple thing to look for next time if they can't afford to buy better equipment.

More importantly, it seems like the least of their worries, with the WAR and all.

2014-04-24 Reply Admin

Cheong:
We used to have straight and crossover wiring configuration for LAN cables. One for connecting machine to network, the other for machine to machine.
Just that modern networking equipments can automatically detect them and make them both works, so the difference become non-existent.

I've read that, but I wonder how it can work. If I connected two notebook PCs by a straight cable I'd expect this: Both detect that they're connected to another PC instead of a switch so both switch themselves. Then both detect that they're connected to another PC instead of a switch so both switch themselves. The loop will exit if one switches so much faster than the other that they both detect an accidentally working configuration before the next idiot iteration. Is that really the right way to do it?

2014-04-24 Reply Admin

Jim the Tool:
So what's the WTF? It can't be the teacher (I've studied networking (admittedly I didn't do very well; I didn't pass), but I didn't know that plugging one port into another would bring down a network (and/or switch). So is the WTF the switch?
captcha jugis. Did the teacher have big jug's?

TRWTF is using an apostrophe to pluralize.

tin · 2014-04-25 Reply Admin

Holy crap... Almost exactly the story I have from school work.

In my case it was a student being funny, not a teacher. And I didn't have an assistant to help track it down.

2014-04-25 Reply Admin

Norman Diamond:
Cheong:
We used to have straight and crossover wiring configuration for LAN cables. One for connecting machine to network, the other for machine to machine.
Just that modern networking equipments can automatically detect them and make them both works, so the difference become non-existent.
I've read that, but I wonder how it can work. If I connected two notebook PCs by a straight cable I'd expect this: Both detect that they're connected to another PC instead of a switch so both switch themselves. Then both detect that they're connected to another PC instead of a switch so both switch themselves. The loop will exit if one switches so much faster than the other that they both detect an accidentally working configuration before the next idiot iteration. Is that really the right way to do it?

Think about it for a while longer. I'm sure you can come up with a better idea than that.

2014-04-26 Reply Admin

anonymous:
Norman Diamond:
Cheong:
We used to have straight and crossover wiring configuration for LAN cables. One for connecting machine to network, the other for machine to machine.
Just that modern networking equipments can automatically detect them and make them both works, so the difference become non-existent.
I've read that, but I wonder how it can work. If I connected two notebook PCs by a straight cable I'd expect this: Both detect that they're connected to another PC instead of a switch so both switch themselves. Then both detect that they're connected to another PC instead of a switch so both switch themselves. The loop will exit if one switches so much faster than the other that they both detect an accidentally working configuration before the next idiot iteration. Is that really the right way to do it?
Think about it for a while longer. I'm sure you can come up with a better idea than that.

Well yeah, I connected them with a crossover cable.

Right, come to think of it, both ports were female so hooking them up meant they weren't straight. I wonder what expertsexchange would say about that.

2014-04-26 Reply Admin

anonymous:
Norman Diamond:
Cheong:
We used to have straight and crossover wiring configuration for LAN cables. One for connecting machine to network, the other for machine to machine.
Just that modern networking equipments can automatically detect them and make them both works, so the difference become non-existent.
I've read that, but I wonder how it can work. If I connected two notebook PCs by a straight cable I'd expect this: Both detect that they're connected to another PC instead of a switch so both switch themselves. Then both detect that they're connected to another PC instead of a switch so both switch themselves. The loop will exit if one switches so much faster than the other that they both detect an accidentally working configuration before the next idiot iteration. Is that really the right way to do it?
Think about it for a while longer. I'm sure you can come up with a better idea than that.

Random delays?

2014-04-26 Reply Admin

chubertdev:
Jon:
What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?

I wouldn't think so. Similar to how you treat a gun as if it's always loaded.

That makes it really hard to clean your guns.

2014-04-26 Reply Admin

Sir Galahad the pure:
anonymous:
Norman Diamond:
Cheong:
We used to have straight and crossover wiring configuration for LAN cables. One for connecting machine to network, the other for machine to machine.
Just that modern networking equipments can automatically detect them and make them both works, so the difference become non-existent.
I've read that, but I wonder how it can work. If I connected two notebook PCs by a straight cable I'd expect this: Both detect that they're connected to another PC instead of a switch so both switch themselves. Then both detect that they're connected to another PC instead of a switch so both switch themselves. The loop will exit if one switches so much faster than the other that they both detect an accidentally working configuration before the next idiot iteration. Is that really the right way to do it?
Think about it for a while longer. I'm sure you can come up with a better idea than that.

Random delays?

Isn't one machine always going to try first?

2014-04-27 Reply Admin

vt_mruhlin:
As I read the thread, it occurs to me that the real WTF is the connector design on network cables. The plug is shaped the same way on both ends, reinforcing this kind of behavior among users.
We don't have problems with users of electricity running an extension cord between two outlets, do we? Because they can't

Ethernet connector design is not a WTF. Ethernet is a bi-directional interface, that doesn't distinguish or prioritize either end of the link. Electricity supply works in one direction, and a live disconnected male plug could kill somebody.

We could make network design much more complicated, or we could just use RSTP...

2014-04-28 Reply Admin

spanning tree protocol kids...spanning tree protocol.

chubertdev · 2014-04-28 Reply Admin

Decius:
chubertdev:
Jon:
What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?

I wouldn't think so. Similar to how you treat a gun as if it's always loaded.

That makes it really hard to clean your guns.

Not really, it just makes you really careful with it.

2014-04-28 Reply Admin

MinorHavoc:
Unfortunately, people have actually used such things. Not only is it very real danger to linemen, that kind of AC extension cable, with two male ends, is called a "suicide cord" for a reason. Don't underestimate stupid.

Also don't underestimate desperate. Imagine it's freezing outside, and your heating while oil or gas fired relies on electricity to work. How long are you going to wait for the electricity company to do their work before resorting to desperate measures to get the power back on to the point that the heating system can fire up?

Granted I personally wouldn't use a widowmaker, i'd find some other way to get the power in (such as disconnecting the wiring from the fuse box and terminal blocking it to an extension lead) but I can see why less electrically minded people would go the widowmaker approach.

2014-04-28 Reply Admin

hydroksyde:
a live disconnected male plug could kill somebody.

Yeah, tell me about it.

2014-04-28 Reply Admin

chubertdev:
Decius:
chubertdev:
Jon:
What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?
I wouldn't think so. Similar to how you treat a gun as if it's always loaded.
That makes it really hard to clean your guns.
Not really, it just makes you really careful with it.

http://www.youtube.com/watch?v=7nzZBku88iw More careful than Monica anyway.

2014-04-29 Reply Admin

chubertdev:
Decius:
chubertdev:
Jon:
What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?

I wouldn't think so. Similar to how you treat a gun as if it's always loaded.

That makes it really hard to clean your guns.

Not really, it just makes you really careful with it.

The rule of thumb that I've heard is to never put your finger on the trigger unless you intend to shoot something. Also, never point the barrel at anything you don't want to shoot.

This would make it very difficult to disassemble the gun. If I've removed the barrel, which part should I assume is the one that's loaded?

Actually the proper safety precaution that I've heard is "always treat a gun as if it's loaded, until you've personally verified that it's not".

2014-04-29 Reply Admin

We tend to use male-male AC cables a lot. Our device does not come with a plug, it is supposed to be powered by a permanent hardwiring of the supply cable to a junction box the factory has fitted on the device. This junction box has a socket to allow us to connect a light or power tool if we need to work on the device.

On occasion we need to modify the mechanical configuration of the device before it is installed in its often hard-to-access and weather exposed permanent location, and these modifications can only be done properly with the power on, as it needs power to various motors to give a realistic impression how it will behave in daily operation.

Instead of messing around with the junction box (where cable glands are permanently deformed when cables are inserted, thus we'd rather save them for the permanent cables) and loose wires (which I guess would be even worse than messing around with a male-male), we put a male-male between a wall socket and the power "output" from the junction box, making it an input.

We have a ban on leaving the device unattended when it is powered this way, even if it's only for a quick trip to the restroom, and the wall plug is always the last to be connected and the first to be disconnected.

Captcha: sagaciter. Someone who cites sagas?

chubertdev · 2014-04-29 Reply Admin

Bill C.:
chubertdev:
Decius:
chubertdev:
Jon:
What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?
I wouldn't think so. Similar to how you treat a gun as if it's always loaded.
That makes it really hard to clean your guns.
Not really, it just makes you really careful with it.
http://www.youtube.com/watch?v=7nzZBku88iw More careful than Monica anyway.

Monica: the world's most famous humidor.

chubertdev · 2014-04-29 Reply Admin

anonymous:
chubertdev:
Decius:
chubertdev:
Jon:
What is the load comes as you're actually holding the wire in your hands? Or are you never supposed to actually do that?

I wouldn't think so. Similar to how you treat a gun as if it's always loaded.

That makes it really hard to clean your guns.

Not really, it just makes you really careful with it.
The rule of thumb that I've heard is to never put your finger on the trigger unless you intend to shoot something. Also, never point the barrel at anything you don't want to shoot.

This would make it very difficult to disassemble the gun. If I've removed the barrel, which part should I assume is the one that's loaded?

Actually the proper safety precaution that I've heard is "always treat a gun as if it's loaded, until you've personally verified that it's not".

I guess that the analogy breaks down since it's not like someone else can easily load the gun while you have it disassembled to clean the barrel.

2014-04-30 Reply Admin

Working in a school (though in a much safer area) I can't tell you how much of this sounded like it was from my own experience.

2014-05-05 Reply Admin

I heard the same tale from an IT officer of a university, the culprit was a post-grad research assistant in department of computer science.

2014-05-19 Reply Admin

vt_mruhlin:
We don't have problems with users of electricity running an extension cord between two outlets, do we? Because they can't

Sure they can, they just wire plugs onto both ends of the cable. Found one like that (live) when I moved in, was a somewhat unpleasant surprise.

2014-06-27 Reply Admin

I'll admit that I have done that once at my school, at the end of the day. Got caught on camera, (I was stupid to do it near a wide-angle one) and the teacher (one of the two guys in IT) talked to me the next day. He asked if I knew what I was doing, and I said I did. I can't remember what kind of switches they used, but they used hubs a lot. I think they still do.

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