Wikipedia:Reference desk/Archives/Computing/2009 August 16

= August 16 =

The power of IP addresses
Out of curiosity, what is the most someone can do with your computer's IP address? (assuming that someone is incredibly good with computers) I'd both like to hear technological answers (i.e. how that person could 'hack'/'crack' your computer using only a computer) and also social engineering answers (i.e. 'hacking'/'cracking' your computer by maybe locating your Internet service provider, calling the company and asking for the owner of that IP address... something like that). I keep hearing that there isn't much one can do with an IP address so I thought I'd ask here --BiT (talk) 00:54, 16 August 2009 (UTC)
 * Just a guess — if you have a dynamic IP, perhaps nothing? And if you don't: I seriously doubt that you could get any information by calling the company, as privacy laws would likely prevent them from telling that kind of thing even if they wanted to tell it to you.  Nyttend (talk) 01:09, 16 August 2009 (UTC)
 * The whole point of social engineering is acquiring information you shouldn't be able to. But the best hacker in the world couldn't do anything to you or your computer if you're not using a static IP? What if you are using a static IP? By what means would the hacker do this? --BiT (talk) 02:05, 16 August 2009 (UTC)


 * You could probe the address, which might get you something. Windows, for example, has a lot of random open ports that it uses for various Windows-y things (and are in most cases not used at all). Assuming the "victim" has an old, buggy, never-updated Windows install, and doesn't use a firewall, there are various tools one could use to totally compromise the machine, execute arbitrary code, etc. If they have a firewall, if they are patched up... not so much, unless you happen to know about unpatched Windows exploits (which are probably out there). (This is how the Blaster worm was able to spread through networks very quickly.) --98.217.14.211 (talk) 04:03, 16 August 2009 (UTC)

The things you can do with an IP address pretty much divide into two categories: sending network traffic to that address, and looking the address up in various sorts of lists.

All forms of "probing" or "scanning" fall into the first category: they involve sending traffic to the IP address and analyzing what comes back. This can include pinging to see if a computer responds, or scanning for open ports to attack them or just to determine what operating system is running. Of course, accessing a Web site or other network resource also involves your computer sending traffic to the IP address of the server or other resource. Another thing that can be done is to traceroute the IP address, which will discover the addresses of Internet routers between you and that address.

The second category, looking the IP address up in a list, includes a lot of different kinds of lists. The WHOIS system is a global directory that includes information on who owns IP addresses (and domains), and can be used to find out what ISP or company controls an IP address. This sometimes also gives you the geographical area. There are both public and private geotargeting databases which can give you the geographical area of an IP address. There are also lists such as DNSBLs which contain IP addresses reported to be involved in spam or other bad activity. --FOo (talk) 06:36, 16 August 2009 (UTC)

Skype lowers the volume on other programs
Whenever I receive a call on Skype, the volume of every other programs (in the Windows 7 Volume Mixer) goes down to almost nothing. How do I stop it? It's annoying. Digger3000 (talk) 02:15, 16 August 2009 (UTC)
 * In your Skype, select Tools then Options. On the window that appears, under General, select Audio settings, then untick the box that says Automatically adjust speaker settings. Should fix it :) 88.105.90.106 (talk) 16:36, 23 August 2009 (UTC)

Using a mobile phone / cell phone as a pocket computer only
I have never had a mobile phone / cell phone. I do not like them, do not want one. But there are lots of old mobile phones knocking around. If I removed the SIM card, would it be possible to use any of them as a pocket computer? Is removing the SIM card enough to make incoming or outgoing calls impossible? Is it just the newest mobile phones that could be used as a pocket computer, or would some older ones that could be obtained free or cheap do this? Functions I would like to use would be using a simple basic-like programming language, reading Project Gutenberg texts, playing puzzle or board games against the computer. Thanks. 78.144.207.41 (talk) 17:24, 16 August 2009 (UTC)


 * If you have no mobile-telephone service subscription, you will not be able to receive calls (except that in some locations, 9-1-1 emergency service calls are available without a subscription). Your phone may also provide a hardware or software "mode" switch to turn off all its radios (many new phones call this "airplane mode").  You should consider what operating system you want to run on the mobile device - some will be more suitable for operation when not connected to the mobile-phone data network; some devices will also have Bluetooth or 802.11 capability for networking independently from the cellular tower network.  Also, have you looked at Netbooks?  Some of these new devices are nearly as small (and cheap) as a "telephone" device.  Nimur (talk) 18:27, 16 August 2009 (UTC)


 * I think there's a mismatch between the OP's "lots of old mobile phones knocking about" and Nimur's "Netbooks . . . these new devices": my interpretation was that the OP wishes to cheaply repurpose an essentially free resource, not spend serious money on a new gadget. Actually, as someone who has also eschewed mobile phones, I'm intrigued by the OP's idea and will be interested in the answers. 87.81.230.195 (talk) 23:27, 16 August 2009 (UTC)
 * I only mentioned netbooks because they are very cheap - new units can be below $200. A quick web search seems to indicate that even a refurbished/used smartphone will start at around $50 if you want something with a QWERTY keyboard (this puts the two classes of devices into overlapping price ranges).  Nimur (talk) 00:26, 17 August 2009 (UTC)


 * Sounds like you should be buying a used PDA. PDA's have somewhat gone out of fashion with fancy modern phones - but they are actually pretty well suited to your needs. SteveBaker (talk) 00:35, 17 August 2009 (UTC)

Thanks. the PDA article says that the first mobile phone / PDA hybrid was in 1996, and that now most PDAs sold are mobile phones, called "Smartphones". I am looking to get something at very little cost, really just as a toy to play with during long journeys. 78.144.246.133 (talk) 13:21, 17 August 2009 (UTC)
 * Yes - exactly. Hence, look for a used PDA on eBay.  It should be cheap (because they aren't trendy anymore and everyone (except you!) wants a smartphone) - and it should still be able to do all the things it did when it was new.  So long as the screen is intact, it should give you years more service.  Looking on eBay right now - you could (for example) pick up a used/refurbished HP Ipaq for $40 (the new ones are still $450!).  It has Windows Mobile, a bunch of apps, MP3 player, etc.  Used Blackberries are on sale for $10 to $25.  SteveBaker (talk) 02:40, 18 August 2009 (UTC)

My Windows XP computer makes very quiet creaking or birdsong-like noises
I only use headphones with the computer. When I scroll an Internet Explorer page up and down using the side bar I get a very quiet creaking noise. When nothing is happening I can hear what may be very quiet tropical birdsong noises. What is this and how can I stop it please? 78.144.207.41 (talk) 17:44, 16 August 2009 (UTC)
 * I have noticed the same sort of behavior. I believe it is EMI (electromagnetic interference) leaking to the input of the audio card's amplifier.  The probable source of the signal is bus transactions (data moving from the processor to other components on the motherboard, particular the graphics card).  I don't think there is much you can do to prevent this; it's an unfortunate side-effect of the closely spaced components and the complicated intermodulation distortion resulting in audio-frequency signals leaking across wires.  Hopefully the next generation of computer design standards will require more stringent RFI and EMI attenuation and testing.  The real trouble is, your audio card has a powerful amplifier designed to take weak digital signals and put out enough energy to drive speakers or headphones - so even very very small interference sources get amplified up to audible levels.  Nimur (talk) 18:20, 16 August 2009 (UTC)


 * Potential solutions include


 * Higher impedance headphones (I think) - may totally fail to solve the problem.
 * Use wireless (eg bluetooth) headphones - the separation of the analogue stage from the computer should eliminate it completely. (not wireless headphones connected via a base station to the audio out)83.100.250.79 (talk) 22:47, 16 August 2009 (UTC)


 * If you have wireless headphones then there may not be much you can do - but if you have wired speakers or headphones then wrapping the cable through a ferrite bead should fix the problem. You can probably buy those in Radio Shack or your local equivalent. SteveBaker (talk) 00:32, 17 August 2009 (UTC)
 * I doubt that would work - unless the actual downmixing is happening at the headphone speaker, which I think is unlikely. I'm pretty sure the interfering signal's already been mixed down to baseband by the time it hits the audio card's amplifier, so you'd need a giant ferrite bead to stop the ~kHz signal - and it'd also cut out a lot of desired audio as well.  Still worth a shot, though... 83.100's idea about bypassing the soundcard altogether with a 100% digital bluetooth headset seems like a more suitable workaround, albeit more expensive.  Of course, this is largely speculative - it's also possible the OP's interference noise is totally unrelated to my original hunch.  Nimur (talk) 00:38, 17 August 2009 (UTC)


 * I too have experiences such issues friends...But my case is different. I use my Memory card reader to transfer data to my SD-Micro card(8GB). recently it's started making sounds like this when ever I copy some data from or to device. And the frequency seems to be in KHz range like a bird chirping. But that sound is generated only when there is any access. It stops as soon the writing\reading is over.Also I have heard the same sound when using blueetooth USB Dongle too.Whenever I connect,speaker starts sounding like this..So this is all due to this EMI?....The thing is I have external video card too...Does this make any issues to my PC life?.... —Preceding unsigned comment added by Balan rajan (talk • contribs) 10:08, 17 August 2009 (UTC)
 * It's certainly EMI - the important question is - Is the noise quite and you have just started noticing it, or is it a new noise that didn't exist before.
 * I've had devices that did similar things, though I didn't actually notice the noise until I had had them for 6months - they continued to work for years after.. However there is a possibility that something has malfunctioned - but I suspect it is small.83.100.250.79 (talk) 20:22, 17 August 2009 (UTC)

The noise from using bluetooth was right from the first day of it's use. I thought it might be RF interference. But this noise arising from using USB-Memory card readers started recently and it's of different frequency than the noise from bluetooth one.Interference is interference,but why different freqs?....Is it EMI and RFI?...If's it's EMI,then it should be 60Hz freq buzz,but what we hear is aroud Khz...What's this issue?... —Preceding unsigned comment added by Balan rajan (talk • contribs) 04:48, 18 August 2009 (UTC)

Strange behavior in Firefox
I'm using Firefox 3.5.2 on Windows XP. When I click on a tab, then quickly click on the "web page" area of the browser, that tab opens in a new window. I have disabled all of my add-ons, and this still happens. Is there some sort of "mouse gesture" setting that I have inadvertently activated? How do I disable this behavior? - SigmaEpsilon → Σ Ε 19:49, 16 August 2009 (UTC)


 * Firefox 3.5 allows you to 'rip off' tabs (drag them between windows, or drag one off the tab bar to create a new window). If you're moving quickly away from the tab bar you may be inadvertently dragging the tab and creating a new window. — Matt Eason (Talk &#149; Contribs) 20:10, 16 August 2009 (UTC)
 * This add-on should allow you to disable this "detach tab" behaviour. 84.12.138.49 (talk) 22:28, 16 August 2009 (UTC)

Handwritten font
Are there any programs that allow you to input your own characters into a scanner to create a font that is your own handwriting? In other words, you basically input every character into a scanner using a stylus or something, and then the computer scans your stroke and uses that as the character. And in order to make it more natural, it can ask for multiple inputs of the same letter, and then when you are typing something, it randomly chooses a glyph assigned to that letter and uses it, so it looks more natural in that you don't have the exact same glyph every time you type the letter "e" (just like in actual handwriting). Has this been done?--12.48.220.130 (talk) 20:45, 16 August 2009 (UTC)


 * There are lots and lots of programs, services, websites, etc. that do this. I think I even saw this advertised in SkyMall once. Google it up, you should be able to find all sorts of things like that. (Here's one site, for example.) I just want to note that while this sounds like a good idea, in practice, handwriting fonts sort of suck, and custom ones, well, you can guess what I think about them. It's unclear to me what situation they would ever really be appropriate in. But hey, it's your money! --98.217.14.211 (talk) 20:51, 16 August 2009 (UTC)
 * They are appropriate for lettering a comic book and other situations where hand lettering is expected. (Certain types of engineering drawings are still done in specialized handwriting fonts, too.) APL (talk) 18:24, 17 August 2009 (UTC)
 * Even then, I would say, go with a professionally-done handwriting font, like the kind Blambot provides. Those are waaaaay better than most people's handwriting. I'm just saying. --98.217.14.211 (talk) 19:08, 17 August 2009 (UTC)
 * I agree that Blambot has great fonts, but for all we know the original questioner might be a professional letterer. APL (talk) 23:40, 17 August 2009 (UTC)
 * Sure, but the odds are against it. --98.217.14.211 (talk) 16:23, 23 August 2009 (UTC)
 * Lifehacker covered this awhile back. &mdash; QuantumEleven 12:51, 17 August 2009 (UTC)
 * The lifehackers article is out of date. Yourfonts.com is no longer free. Strangely, YourFonts.com and FontBay appear to be using the same templates, offering the exact same service, and charging exactly the same amount. APL (talk) 18:21, 17 August 2009 (UTC)
 * I've never seen software that will randomly vary glyphs. The closest I've seen are comic-book style All-Caps fonts where the upper case and the lower case are subtly different versions of the same glyph. I suppose you could randomly pound on the shift key. But fonts like that are rare. APL (talk) 18:27, 17 August 2009 (UTC)
 * Theoretically, a font that provided a lot of ligatures and character variations (see Zapfino for examples) could do this really well. But I don't know of anyone who's done this, and it would be a buttload of work. --FOo (talk) 01:56, 18 August 2009 (UTC)