Wikipedia:Reference desk/Archives/Computing/2015 June 26

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June 26

Strange (possibly fraudulent) phone call

I received a phone call on my land line this afternoon, which caller ID said was coming from area code 404, which is greater Atlanta. The person said that he was calling from Microsoft engineering, and needed to talk to me about my Microsoft Windows computer. He said that they were getting messages from my computer about its files, and that I had a problem with my files, and they asked me if I would sit down at my computer so that they could help me. I didn't entirely understand what they were saying was wrong, but they were saying that my computer was either using a lot of resources or that it was using a lot of files, or something. I said that I had not gotten any email from them, and that they should contact me by email if they really were legitimate. He said that they only used email to test, and that when they actually determined that there was a problem, they just phoned and asked me to sit at the computer. He continued to say that he was only trying to help me. I said that, since I didn't know who he was, I wasn't going to give him access to my computer, because he might be trying to install a keystroke logger or spyware. He insisted that he was only trying to help me. Eventually I asked if I should call either the police or the Federal Communication Commission. I wound up hanging up. Robert McClenon (talk) 01:56, 26 June 2015 (UTC)

The first sign that something might be wrong is that, when I answered, he didn't ask for me by name, and, if he really was receiving trouble reports from my computer, it would have provided some information, such as, at least, the name of my computer, and maybe the email address used in Outlook on the computer. Robert McClenon (talk) 01:56, 26 June 2015 (UTC)

My question is whether this is a known scam/problem, or whether this is something new. What was the caller trying to do? Was he calling land-line phones randomly, or getting my number from some list? What was he trying to do? Robert McClenon (talk) 01:56, 26 June 2015 (UTC)

Scam: [1]. AndyTheGrump (talk) 01:59, 26 June 2015 (UTC)

These are common enough that we even have an article Technical support scam and Microsoft themselves have a warning page [2], as well as the usual suspects [3] [4] [5] [6] [7]. AFAIK most of these are operated from outside the US in places known for cheap call centres particularly India. In the VoIP world the area code can easily be meaningless. [8] [9] does mention some US companies, but it sounds like these are websites rather than cold callers, and in any case whatever the wisdom of setting up a company like that in the US, it doesn't say much about where their call centre is. (The second source does mention some calls with a US area code.) You can see some examples of people engaging with such callers here [10] [11] [12] Nil Einne (talk) 02:15, 26 June 2015 (UTC)

I got one of those calls a few weeks ago. He said that my Windows computer was having issues, so on and so forth. I just laughed. The computers in my house run either Mac OS X or Linux. Never Windows. Good job keeping your head about you when they called! Dismas|^(talk) 02:46, 26 June 2015 (UTC)

My parents get them at least once a week: they have never owned a computer. {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 13:07, 26 June 2015 (UTC)

• A month ago, when "John from Windows Support Center" announced himself, I cheerily asked him to tell me more about Windows Support Center. He immediately hung up. — Sometimes I'm tempted to fire up my Windows virtual machine and follow instructions to see what happens, then restore the VM from backup. —Tamfang (talk) 06:30, 27 June 2015 (UTC)

Not answered

Thank you. My original question has not really been answered, except that everyone agrees that it was some sort of scam. What exactly was he trying to do? Was he trying to turn my computer into one of his zombies? By the way, I am essentially certain that the call was coming from area code 404 (and that could be a bad pun), because I don't think that calls from outside the United States are able to spoof area codes. Was he randomly calling land lines? Robert McClenon (talk) 15:20, 26 June 2015 (UTC)

It's answered in the paragraph beginning "The scammers then perform questionable tasks to "repair" the system" in Technical support scam. -- Finlay McWalterᚠTalk 15:31, 26 June 2015 (UTC)

Okay. Perform questionable tasks, such as turn the computer into one of his zombies. Robert McClenon (talk) 15:41, 26 June 2015 (UTC)

And steal your email credentials, empty your bank account, buy stuff on your Amazon account, and get enough personal information on you to take out credit in your name. Congratulations, you now own a speedboat in Macao. -- Finlay McWalterᚠTalk 15:47, 26 June 2015 (UTC)

The Caller ID spoofing article confirms what Nil Einne said - spoofing callerID is easy, particularly on VOIP, and your essential certainty that the call was from area code 404 is entirely misplaced. -- Finlay McWalterᚠTalk 15:47, 26 June 2015 (UTC)

I have another comment. This caller was stupid as technical support scammers go, although maybe all technical support scammers are stupid. He didn't have the sense to give up and move on to another victim when I said that he was trying to install a keystroke logger. At that point he should have known that he wasn't going to succeed, but maybe all technical support scammers are too stupid to figure out whether they are going to succeed, and just keep on trying. Robert McClenon (talk) 15:26, 26 June 2015 (UTC)

He didn't have the sense to move on, but maybe technical support scammers don't have the sense to move on, because maybe they have enormous egos and enormous confidence in their own power of persuasion and social engineering. Robert McClenon (talk) 15:41, 26 June 2015 (UTC)

Every minute you stayed on the call with him was a success for him. When he cold called you, he didn't know it was a domestic residence - now he does. He didn't know there was a computer there, now he does - and you probably confirmed to him that in runs Windows, and probably what version. In these kind of circumstances people try to refute the con-man's assertions with facts - "that can't be, we have a new AVG pro installation"; "my son set this computer up - he's very good with things like that" or partial confirmations "we have had trouble connecting to comcast"; "ESPN hasn't been working today - is that connected?". Even your threats tell him something "I'll call the FCC!". And the fact that you stayed on the line with him (for what sounds like 10 minutes or more) tells him you're susceptible to this kind of scam. He can sell this information, or pass it to a colleague who is far more credible sounding. So if you get a call in a couple of months from Comcast, or AVG's tech support, or the FCC's phone scam investigation department, from a professional sounding American lady with a DC area code, there's a greater chance of it working. -- Finlay McWalterᚠTalk 16:17, 26 June 2015 (UTC)

I don't understand. What are you saying I should have done differently? Robert McClenon (talk) 17:06, 26 June 2015 (UTC)

The fact that it isn't obvious is the problem. You did not gain anything by talking on the phone. You will likely get more calls now that you have proven that you are willing to talk. What should you do? Hang up. 209.149.113.97 (talk) 17:21, 26 June 2015 (UTC)

When it became clear that they didn't know your name, you should have put the phone down on them. There's a great deal to be said for letting all calls from unrecognised or withheld numbers go to voice mail - genuine callers will leave a message, telesales and scammers mostly won't. I think about 95% of the calls I get, that aren't from individual people I already know, are some species of junk. -- Finlay McWalterᚠTalk 17:26, 26 June 2015 (UTC)

Their main target are the large numbers of old people. In today's world you can hardly do without a computer with internet access. If you had little experience with using computers and the internet all your life until the age of 85 and have only recently started to do online banking, then you are an easy target for these scammers. So, it could be that Robert's voice or the way he talks makes him sound like an old person. Count Iblis (talk) 18:27, 26 June 2015 (UTC)

Creepy i.p. storage

I have used various wikimedia projects for roughly 8 years as an i.p. This year is the first time I regularly see my i.p. being remembered. For example edits I made 3 months ago show up in my i.p. history. In other words I regularly get the same i.p. I used ages ago. I feel uncomfortable with this and would like to know why its happening. I feel like wikimedia has my computer stored on their devices and am freaked out and scared by that. Help.84.13.27.150 (talk) 16:44, 26 June 2015 (UTC)

Wikimedia does not control what IP is assigned to your computer. Your ISP does that. If you don't like getting the same IP you used to use, switch to a different ISP. 209.149.113.97 (talk) 17:00, 26 June 2015 (UTC)

A list of your contributions can be seen here: [[13]]. Wikipedia does not have a lot of information about you. Besides the fact that you are in London, there is not much tha can be extracted from that information. --Yppieyei (talk) 17:24, 26 June 2015 (UTC)

Just to be more specific, the IP address doesn't give out information about the user. What the user submits could be different. If I used this IP to post that I am a prisoner in Edgefield and I want help on the paper I'm writing for my BS degree at Furman, then it would be MY fault that I posted information about myself, not my ISP-assigned IP address. 209.149.113.97 (talk) 17:41, 26 June 2015 (UTC)

Yeah - the IP address DOES give out information that anyone can find...specifically, you can find the name of the ISP the person is using...which generally also tells you roughly where they are in the world (which is how Yppieyei knows you're probably in London). Creating an account hides that information - so ironically, you have more privacy if you create an account than if you don't. If you're really concerned about privacy, you should worry that knowing your IP address (at least for a few hours after you post) would give a hacker the ability to go and attack your computer remotely...which is why I have always edited here with an account name. SteveBaker (talk) 00:52, 27 June 2015 (UTC)

What's going on here is that your computer almost certainly doesn't have a single IP address that you are personally assigned. There aren't enough unique IPv4 addresses available in the world for many ISP's to give everyone their own. So they are shared. When you turn your computer on, it doesn't know what it's IP address is - so it uses a special protocol called "DHCP" to request an IP address from your ISP's computer. Once your computer has an IP address, it uses it to talk to Wikipedia - and that's what Wikipedia stores for your edits and signatures. The detail that matters here is that your ISP's computers can implement the DHCP protocol in many different ways - there are no hard-and-fast rules about that.

Some ISP's give you a different IP address every time you turn your computer on. Some others give you a new IP address every few hours. Yet others go to the trouble to try to always give you the same address you had the last time...but without any kind of a guarantee that it'll be available. These numbers may be selected from a relatively small pool (maybe just a hundred or so addresses that differ only in the last number) - or they may come from a pool of millions of addresses. But these days, most ISP's try to give you the same IP address every time you turn your computer on - they won't always succeed, but they quite often try.

So if your ISP handed out IP addresses at random from a large pool, the odds are small that you'd see your own edits in the edit history for whatever IP address you're currently using...but if they then switched their DHCP policy to the approach where they try to give you the same address every time - or to selecting from a small pool - then you could go for months without seeing a different address pop up and you might see the same handful of addresses popping up over and over again.

You're not going to be able to change how your ISP allocates addresses via DHCP - so (as others have said), you'd have to switch to an ISP that uses a different policy. It would likely be very hard to find out what their policy is in advance...it's not the kind of thing that their sales or tech support people are likely to be very knowledgeable about.

If you're relying on randomly assigned IP addresses for some kind of security/privacy reason...that's an entirely unreliable proposition and you're basically screwed. As IPv6 gradually replaces IPv4, the number of IP addresses available increases spectacularly - and it's much more likely that your ISP will keep the same address for you indefinitely because most people who care prefer it that way.

SteveBaker (talk) 00:47, 27 June 2015 (UTC)

With a normal home broadband installation, it's more likely that the computer itself would get its (private) IP address using DHCP from the user's local router/modem. The modem would probably be a cable or DSL modem, and it would get the public IP address from the ISP with either PPPoA or PPPoE.--Phil Holmes (talk) 10:49, 27 June 2015 (UTC)

Why pdf files do not use Unicode?

According to Portable_Document_Format#Encodings, in pdf files "characters are shown using character codes (integers) that map to glyphs in the current font." Wouldn't that imply that you always have to embed the font in the document, or hope that it's already installed in the user's machine? Why not use Unicode? --Yppieyei (talk) 17:22, 26 June 2015 (UTC)

Fonts

My understanding is that PDF files are mainly intented to represent printed paper documents and have the exact same appearance in every viewer. My understanding is you do normally embed the font (or a subset of the font containing the glphys the document actually uses), or hope the specified font is already installed on the user's computer.

The second sentence of Portable Document Format says "Each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, graphics and other information needed to display it." I assume "fixed-layout flat document" means something like "represents a printed paper document and has the exact same appearance in every viewer".

Unicode

In most PDF files, you are able to select the text, copy it, and paste it in other programs, so I assume the PDF file also stores some standard character code (maybe Unicode) for the copy-and-paste ability.

The section you linked to (Portable Document Format § Encodings) seems to describe PDFs normally use an encoding based on Windows or Macintosh OS and says "For large fonts or fonts with non-standard glyphs, [...] it is necessary to provide a ToUnicode table if semantic information about the characters is to be preserved." So it sounds like Unicode may be used for textual copy-and-paste ability.

--Bavi H (talk) 00:11, 27 June 2015 (UTC)

But if the file stores integers representing glyphs of the font (which is embedded) and includes a Unicode representation, you'll end with redundant information in it, at least in this concrete case, where you want to allow copy-and-paste, for example. What could affect the appearance if you had Unicode only + the embedded font in the file? --Yppieyei (talk) 00:35, 27 June 2015 (UTC)

PDF predates the wide adoption of Unicode by years, and it borrows a lot from PostScript, which predates Unicode 1.0 by a decade. That's the only reason, I think. -- BenRG (talk) 00:58, 27 June 2015 (UTC)

How to align a div

i want to align the div which inside another div to center, how to do that ??123.238.96.132 (talk) 18:01, 26 June 2015 (UTC)

like this

margin-left: auto; margin-right:auto; being the important thing. -- Finlay McWalterᚠTalk 18:28, 26 June 2015 (UTC)