Wikipedia:Reference desk/Archives/Computing/2017 September 7

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September 7

Stupid censorship question

For the past few weeks I've been following the troubles of Daily Stormer, which has been repeatedly denied basic DNS service. What I don't understand is that each time it actually has a DNS address, you can just "nslookup a dailystormer.whatever" and get some location like 198.251.90.113, which is a typical IP address that has a typical whois with some random company official who can and presumably is being hit with the typical tide of complaints, DDOS attacks, death threats etc. until the last quixotic believer in freedom of expression is purged from the internet. So the part I don't get is why do I keep reading about the attacks on the DNS servers and cave-ins by their maintainers and not attacks on the actual IP addresses of the magazine? Wnt (talk) 02:26, 7 September 2017 (UTC)

Respondent appears to have admitted their comment had zero to do with the topic Nil Einne (talk) 14:57, 9 September 2017 (UTC)

If it's a read-only site, there's not much you can do to it directly. On the other hand, if they sell things or allow comments, then a Denial of Service attack is possible. (A DoS is technically possible with a read-only site, but they won't lose revenue from it, so can just wait until it ends.) StuRat (talk) 02:48, 7 September 2017 (UTC) I don't understand the relevance of 'read only' here. A site which is trying to make money will lose revenue from a DDoSed regardless of whether it's read only. A site which isn't trying to make money is not going to lose revenue if it's DDoSed regardless of whether it's read only. Even when a site is nominally not read only it isn't uncommon the non 'read only' part of it is mostly irrelevant. For example it's possible the NYT, CNN, Fox News, the WSJ and the Washington Post allow comments or other user interactions but the importance of these pale in comparison to the read only parts. When people DDoS them they are almost universally trying to stop people seeing the 'read only' parts and may not care at all about the non 'read only' parts. Also your response doesn't seem to answerthe question namely why target the DNS server rather than the webserver. Nil Einne (talk) 07:16, 7 September 2017 (UTC) It may be that StuRat is under the impression that you cannot DoS a "read-only" site. Which is wrong, since "reading" (i.e. getting the HTML page) involves a query of the server (see Transmission Control Protocol and HTTP). It may be that the POST attack could not work on "read-only" sites but I do not know if it is feasible (and if it is, whether it is common practice) to deny all POST requests for such domains. TigraanClick here to contact me 08:21, 7 September 2017 (UTC) Except that StuRat said "A DoS is technically possible with a read-only site, but they won't lose revenue from it, so can just wait until it ends" so they seemed to know it was possible to DDoS (or at least DoS) a read only site. This is of course often all you can do with a DDoS, wait it out read only or not. I mean okay there are mitigation measures, but most of them don't relate to whether or not your site is read only and they don't tend to work that well if the DDoS is powerful enough beyond simply having a CDN capable of surviving the DDoS which is one thing which by and large works whether or not your site is read only or not. The only real difference I can think of is that since the CDN probably isn't providing the back end elements to support the non read only elements, it's possible that a DDoS could over whelm these, but most CDNs dedicated to protecting from DDoS, like CloudFare, tend to have various measures to try and prevent that from happening. Of course if the DDoS is in the form of a spam attack on these non read only elements, you will need to counter that, but this form of attack isn't very common. About the POST vs GET point, I'm fairly sure quite a lot of DDoS actually rely on on some form of amplification, e.g. DNS amplification so the actual traffic received by the target isn't even something it's expecting or necessarily understands. [1] [2] [3] [4] [5]. I'm not sure however what the attacks relating to DailyStormer did. Nil Einne (talk) 09:17, 7 September 2017 (UTC) My point was that an organization dependent on revenue from their web site could be forced out of business by repeated DoS attacks, while one which only uses their web site to provide info can afford to just wait it out. StuRat (talk) 14:27, 7 September 2017 (UTC) But this has zero to do with whether a site is read only, and for that matter whether the site only provides info. As I said, many sites which are read only only and incidentally only provide info are reliant on their websites for the revenue. Maybe the examples I have weren't the best since many of them are also offline news souces but there are websites which are solely commercial online news sources. (There's of course also the cross counter of sites which often don't make much revenue directly but still are a very important part of the revenue stream. Microsoft for example, although they do have their webstores and subscriptions nowadays these are likely still a minor part of their revenue. Yet both now, and when these were less important, stuff such as the knowledge base and MSDN were often very important to their revenue stream despite only providing info and other data, and being often read only and not the sort of thing they want down even for a day. Not to mention updates tend to come basically from a website.) Meanwhile forums are not read only (unless they're archives) and some of them don't rely on revenue. Some forums do ask for donations (others have premium memberships etc which are more directly selling you a product, have ads etc), but not all do as some are just pet projects or whatever of the owner (often donations etc only come into it when they get too big). And incidentally it seems that the Daily Stormer was at times asking for donations too [6]. (Frankly I'm not really sure where donations fit into your limited world view. Donations are of course a funny thing, many people here think the WMF get way too many of them, and while they do have their campaigns, not all of them directly come from those campaigns but from direct approaches with large donors. Yet whatever people may think of the way the WMF spends their money, wikipedia is surely a key part of why they get those donations, even in those instances where they come direct from large donors and are there's an agreement to direct them at something else.) And funnily enough, I've confirmed while researching this your claim about read only isn't even correct. Daily Stormer did have a BBS which they used for comments on stories, for example. You did mention revenue, as you do now, but you keep also making incorrect points about 'read only' and 'info only' which makes it sounds like you're someone from an out of contact tribe in Africa or South America who has never actually used the internet and have no idea how it works, and doesn't work since I imagine basically everyone else here, knows that a site being 'info only' or 'read only' doesn't mean they don't make revenue from it, and that a site being not 'read only' doesn't mean they do. You seem to be trying to make a point about sites like Amazon and other sites which directly sell you products but ignored the fact that many, many sites are not like that, but still are either the only or a very important part of a companies revenue stream and not something they can really simply afford to leave down. Google and Facebook are of course a famous example where people keep saying including here on the RD that you are the product because most of their money doesn't come from direct sales to the end user. Although as I said, if you aren't a massive company or have one behind you, whatever your business model if any you often have limited choice but to wait out a DDoS. Since while there are mitigation measures most of which have little to do with whether your site is read only or info only, they can't generally completely counter most types of dedicated DDoS. In fact whether or not you're a commercial enterprise where your website is an important part of your enterprise or an advocacy or misinformation campaign, doesn't necessarily affect the availability of mitigation measures except that a commercial enterprise may be more likely to be able to afford them, or more desperate too. But then again, there are a lot of very rich donors out there. And so for example, very near the end of an election campaign, there's a good chance for some sites which are basically read only info only advocacy or misinformation sites have a lot more money and desire to keep them up, than August D'Angelo's business selling home made cat hats even if that's the only way they sell them. (In case it's not obvious, this is a made up example.) I'd add that something like CloudFare isn't that expensive and even free for some [7] [8]. While they did cut off DailyStormer, they have said they're generally very reluctant to do so regardless of how controversial the site is. And provided your actual usage fits the plan you subscribed to, I'm not sure how much they care that you're a big target unless perhaps you're specifically doing things to encourage it (as opposed to just doing things which annoy people), although obviously the less you pay the less sophistication and support etc you get. And incidentally, since Amazon came up, there are sites like ToysRUs and Walmart for example, where the sites are both used for direct sales and for info for their retail stores a bit like Microsoft except with sales via the website being more important. Yet despite Amazon basically being nearly completely reliant on their website (and app etc which likely rely on the same components), they could actually probably better afford to have their website down for a few days despite the massive disruption and loss of revenue because of how big they are compared to some other smaller retail stores where the website is also an important part of their revenue stream (so probably not ToysRUs Or Walmart). Of course good luck DDoSing Amazon, Microsoft, Google, Facebook but the points stands. In other words, your comment didn't actually make your point. It said something else. And it wasn't even that good a point since while it's true whether or not a site is making revenue partly reflects whether or not they can afford to wait it out, it's not the only measure by far. Nil Einne (talk) 06:30, 8 September 2017 (UTC) You misrepresent me as having made claims about what type of web site The Daily Stormer has/had. I made no such claims. And, of course, there's a continuum from a company 100% dependent on their web site for revenue and those 0% dependent. Those with web stores, and no brick-and-mortar stores, will likely be closer to 100% and those without, closer to 0% (there are always exceptions, of course, such as revenue from ads). So, back to my point that a company highly dependent on it's web site for revenue can be put out of business by cyber attacks, while one that is less dependent can wait it out. StuRat (talk) 16:12, 8 September 2017 (UTC) My main point was you said completely stupid things which you did any anyone can see that. If it's a read-only site, there's not much you can do to it directly. On the other hand, if they sell things or allow comments, then a Denial of Service attack is possible. (A DoS is technically possible with a read-only site, but they won't lose revenue from it, so can just wait until it ends. }. Let me repeat for the last time, whether a site is read only or not or whether they allow comments or not, has nothing to do with whether they can be DDoSed, nor whether they can survive being DDoSed. And let me repeat, the claim that Daily Stormer is read only is simply not true anyway. They do allow comments. So this comment was wrong in every single way, and therefore completely irrelevant. If you're admitting that your comment had zero to do with the questions since you weren't talking about Daily Stormer but making random general comments, I might as well collapse this discussion. Don't blame me for assuming that sicne you were replying to Wnt you were actually trying to help rather than making random general comments which had nothing to do with the website in question. My point was that an organization dependent on revenue from their web site could be forced out of business by repeated DoS attacks, while one which only uses their web site to provide info can afford to just wait it out. As I've made clear, an organisation can be entirely dependent on revenue from their site despite it being "info only". It's true an organisation depend on revenue from their website could be forced out of business by a DDoS, that's a non sequer and also irrelevant. Nil Einne (talk) 14:57, 9 September 2017 (UTC)

Are you sure only their DNS servers were DDoSed? For example, DreamHost was one of the targets [9] and while some of the sources confirm their DNS servers appeared to be affected it's not clear to me their web servers weren't. In any case, many of their recent hosts seem to have been like DreamHost and provided both DNS and web hosting. CloudFare also provided both DNS and CDN [10]. So ultimately whether you target their DNS hosting or web hosting or both you have the same company targeted. Their current host is definitely new [11] [12] [13]. I'm not sure if their current host provided DNS hosting but it's not like finding DNS hosting has been the issue anyway. The problem is they keep losing their domains, for reasons nothing to do with DNS hosting. Nil Einne (talk) 07:59, 7 September 2017 (UTC)

P.S. I've perhaps oversimplified the difference between the CDN component and the reverse proxy component of something like CloudFare, although despite the pointless diversion above about read only sites, I'm not sure if it's that important in the context of this question. Nil Einne (talk) 05:57, 8 September 2017 (UTC)

@Wnt: See https://imgs.xkcd.com/comics/free_speech.png and https://blog.cloudflare.com/why-we-terminated-daily-stormer/ (((The Quixotic Potato))) (talk) 08:07, 7 September 2017 (UTC)

Also, if the site has simple text-only pages, as opposed to many pics and, even worse, videos, it won't take much data transfer to load the page, so you would need a lot more page requests to cause a DoS. If they have some simple protections, like not allowing more than one page load request from an IP per second, this should help. StuRat (talk) 14:38, 7 September 2017 (UTC)

Except as I already mentioned before your reply, many DDoS don't rely on requests the site even understands. They may use DNS amplification or other forms of amplification to simply flood the site with traffic. Do you have some statistics on how many DDoS actually rely on HTTP Flood or otherwise requests to generate responses from the target site? I've looked and couldn't really find any. I can find stuff like [14] which has general statistics, but it's hard to say from them how much of a component they are. Because there are various mitigation measures, which can significantly reduce the effects depending on the sophistication of the attacker and defender [15], I'm not sure how common these are nowadays compared to other types of attacks except perhaps when you know they will work (e.g. because whoever set up the site isn't very good) or there's limited alternative (e.g. possibly attacks to Tor sites). Although I'm pretty sure this type of thing is also very clustery. Someone figures out a method of attack that works well, and everyone uses it until it stops working, perhaps because enough people fix their services that it no longer works. HTTP Floods are to one extent something where that doesn't apply however as just mentioned, actually generating and countering them is an arms race including the source of the attacks [16] [17] Nil Einne (talk) 06:30, 8 September 2017 (UTC)

You can also perform DDOS attacks s l o w l y.[18] A Quest For Knowledge (talk) 16:36, 8 September 2017 (UTC)

I remain confused. I should note however that the nslookup still goes to the same IP address as yesterday. Going to the IP address gets a "domain not in our systems" message from BitMitigate. Going to dailystormer.at gets to a continually-reloading page. If scripts from dailystormer.at and bitmitigate are enabled (I hope I didn't catch anything...) this will currently crank for a bit and display the Daily Stormer site. (Note that Tor not only can display the same site without scripts, but despite media unanimity to the contrary seems to do it faster, at least if you don't count the 30-second wait when you first start the Tor browser before you can type the address) Now I have to admit that obviously BitMitigate is doing something very clever and fancy whose understanding is the difference between typing on Wikipedia and being the CEO of a tech company. But I don't get how the people listed in the whois for the IP address, and the machines that reach them, have managed to hold out against hostile hordes. Wnt (talk) 17:58, 8 September 2017 (UTC)

I don't understand why it surprises you by going to the IP directly doesn't work. That's the case for a very large number of webservers. There's nothing special, unique, or hard about it. (Try visiting https://198.35.26.96 for example.) It's especially the case for anything set-up with complicated back end, like you may have if you want to resist DDoS. Although to be clear, having the IP itself not work is not really a major component of countering DDoS, rather it's simply reflectiv of the set-up.

I'm not entirely sure if dailystormer.at has held out entirely against the 'hostile hordes' since when I visited it earlier to check for my answer above, it didn't seem to work although I didn't try particularly hard. But in any case, I'm not sure why it's so hard to believe if it has happened. For starters, it's not clear to me there is actually that much DDoSing going on. Sure people are still getting their domains shut down, but I didn't actually seen any talk about DDoS (or DoS) of Daily Stormer that is recent. (Actually most of the talk about DDoSing seems to be just after CloudFare dropped them, whoever was hosting them then, when they moved to DreamHost, and also on their Tor dark service. And actually, now that I look at it, I'm not sure the possible DDoS after CloudFare dropped them was a DDoS of the DNS servers.)

This is nearly always what happens. Someone gets sufficiently bored/annoyed/whatever and uses some botnet they have (or buys one) to DDoS a site. Then they get bored of that and move on to something else. I mean I'm not saying there are no minor attacks, there may be, but there's a very good chance they haven't actually faced major challenges since late August. (I mean okay, the BitMitigate CEO or whatever seemed to be almost trying to get DDoSed with their comments, but people don't always care enough about such things.)

In any case, even if they have had major DDoS attempts, it's not like it's always impossible to survive a major attack. I'm fairly sure CloudFare for example probably could survive the majority of attacks, that was after all what they said, those who wanted to DDoS dailystormer were asking CloudFare to abandon them. And while yes, this may be a bit of grandstanding the history strongly suggests that CloudFare is fairly resilient. (Also I'm fairly sure that CloudFare wasn't the only one who said it.)

It is true, as CloudFare said, that if it is a dedicated enough DDoS the number of services besides CloudFare which could survive it isn't very high. BitMitigate themselves may not be that, but if you read the links I provided above, it seems the people they're getting services from (or rather the people they in turned hired) may or may not be able to do so. Incidentally, I'm not sure why the website doesn't work for you with scripts disabled, it works fine for me.

Nil Einne (talk) 16:09, 9 September 2017 (UTC)

A url for producing the raw text of a random featured article?

Hello,

For a machine learning project I need a url that would produce the raw text of a random featured article in Wikipedia as a .txt file. By raw text I mean only the article itself (not the entire html page) and with square brackets for internal links etc. Preferably I want an option to specify the language as well. Does something like that exist?

For example - the following link produces the raw text of a random article (not featured article) in Hebrew Wikipedia: https://he.wikipedia.org/wiki/Special:Random?action=raw

Thanks! — Preceding unsigned comment added by 77.127.95.225 (talk) 08:17, 7 September 2017 (UTC)

• I am not aware of such a URL, but is that really necessary? If all you want is for the program to pick out a random article, you can do the randomness yourself.

Featured articles are listed at Wikipedia:Featured articles. I suggest you parse the latter page to generate a list of the page titles of featured articles, pick out a random item from the list by your own program's pseudorandom generator, and pull that article via the API. (I imagine you could host a web server that gives a request URL that redirects to a random FA by this process, though I fail to see the point.)

If you intend many queries (as seems to be the case in "machine learning project"), please see mw:API:Etiquette before starting. Tigraan^{Click here to contact me} 08:36, 7 September 2017 (UTC)

Thanks for your answer. I Just thought this approcah would be faster. Could you direct me to instructions specifying how do I get the raw source code text of an article via the API (I'm working in Python)? — Preceding unsigned comment added by 77.127.95.225 (talk) 09:13, 7 September 2017 (UTC)

With http://tools.wmflabs.org/erwin85/randomarticle.php I produced this link to get a random article in Category:Featured articles: https://tools.wmflabs.org/erwin85/randomarticle.php?lang=en&family=wikipedia&categories=Featured%20articles&namespaces=-1. Category:Featured articles (Q4387444) shows the category name for featured articles in many languages. PrimeHunter (talk) 10:41, 7 September 2017 (UTC)

Well, PrimeHunter's solution looks good if you can extract the code from the page it redirects you to. But in case you need to work with the API in Python...

It is probably better-coded elsewhere, but you can take inspiration / copy-paste from this (I encourage you to pull the user-agent identification snippet as well, and populate it with your own info). Using api_call with parameters {'foo1': 'bar1','foo2': 'bar2',...} in a Python dict will request the URL en.wikipedia.org/w/api.php?foo1=bar1&foo2=bar2&.... Then see mw:API:Revisions with action=raw.

This produces stuff such as [19]. Is that the format you are looking for? Tigraan^{Click here to contact me} 15:59, 7 September 2017 (UTC)

You could do it as a two-stage process. Go to https://en.wikipedia.org/wiki/Special:RandomInCategory/Featured_articles figure out the url that you were redirected to, and suffix it with "action=raw".

ApLundell (talk) 17:01, 7 September 2017 (UTC)

Excel Formula sought

I have columns with titles “Unit(s)”, “Costs” and “Unit(s) bought”, “Unit(s) left”, “Spent”, “Leftover”. I filled “Unit(s)” and “Costs” column manually and “Leftover” column automatically (integrated with "Spent" column), now formulas are required for the “Unit(s) left” and “Spent” columns so that every time I insert number(s) in the “Unit(s) bought” column, auto result displays on both… Could you help me please? 103.67.156.84 (talk) 17:11, 7 September 2017 (UTC)

To make sure that we have understood what you need, could you give an example with numbers, and are we correct in assuming that the columns are A to F (and that there are no hidden columns)? Dbfirs 18:48, 7 September 2017 (UTC)

Column A: Unit – pre-set data available here.

Column B: Costs – pre-set data available here.

Column C: Units bought – data will be inserted here.

Column D: Spent – require a formula that understands column “A”, “B”, “C”.

Column E: Units left: require a formula that understands column “A”, “B”, “C” and “D”.

Column F: Leftover: require a formula that understands column “A”, “B”, “C” “D” and “E”.

::Note:

I’ve used ‘minus’ sign on column “E” and “F”. Formula looked something like:

A–C for column “E”, and

B–D for column “F”.

What I wish for is, to insert value in column “C” so that “D”, “E” and “F” are displayed automatically.

116.58.200.14 (talk) 14:58, 9 September 2017 (UTC)

If I've understood correctly, then you've already got your formulas for columns E and F, and I assume that D is just B multiplied by C, but perhaps you meant something different (how does it involve A?) which is why I asked for an example with numbers.

If row 2 is the first row with numbers, then in cell D2 you type =B2*C2, and in cell E2 you type =A2-C2, and in cell F2 you type =B2-D2. You then highlight these three cells and replicate (copy) them down as many rows as you need.

This is all very basic usage of Excel, so perhaps there are some subtleties that I've missed? Dbfirs 20:26, 9 September 2017 (UTC)

Dbfirs:

My English is not very well. I hope the following is clearer Thank you for your time…:

Column A: Unit(s) – pre-set data is available here in this column’s row’(s) cell(s), say for example, a number from “1” to “10”.

Column B: Costs – pre-set data available here in this column’s row’(s) cell(s), say for example, a number from “10” to “20”.

Column C: Unit(s) bought – data will be inserted here manually as when required, say for example, a number from “1” to “10” or “1” to “50”, depending on the requirements.

Column D: Spent – formula required for auto result display.

Column E: Units left – formula required for auto result display.

Column F: Leftover money – formula required for auto result display.

Note:

Formula required for column “D”, “E”, “F”’s row(s) cell(s) so that auto result is displayed altogether, in each cell (D, E, F), whenever I insert value(s) in column “C” only. Using one cell manually to display 3 cells result basically.

103.67.157.67 (talk) 03:37, 12 September 2017 (UTC)

Did my suggestion not produce the results that you needed? Could you explain what displays incorrectly? Do you want to suppress the display until values are entered in C? Dbfirs 19:39, 12 September 2017 (UTC)

Recovering pendrive’s datas

When you recover a pendrive’s datas, what do you recover?:

1) only the last inserted files and folders.

2) everything since the beginning of time.

103.67.156.84 (talk) 17:11, 7 September 2017 (UTC)

Same as most drives. Everything since the start, so long as it hasn't been overwritten since. This is why, when doing any recovery work, it's important to not write anything new to the drive (such as downloading the recovery software to it) while you're working on it. Andy Dingley (talk) 17:46, 7 September 2017 (UTC)

Free advice: back up your data multiple places so that the next time you don't have to do any data recovery. --Guy Macon (talk) 06:23, 8 September 2017 (UTC)

While data recovery from USB flash drives is often like from magnetic hard drives, I have found this isn't always the case. USB flash drives don't generally support TRIM but they do generally have some sort of wear leveling implemented on the controller, and precisely how this interacts with deletion seems to vary, even if the data isn't actually zeroed or nominally overwritten I have found odd behaviour. That said, all you can do with try, although even more so than hard disks, I would recommend imaging rather than dealing directly with the USB flash drive, and maybe even keep a copy of the image to reduce the possibility of screw ups (although realistically most recovery software doesn't even have the option to write). And imaging ASAP even, if the device is plugged in, even if not mounted so you think nothing should should happen. I do agree with Guy Macon that the best solution to data recovery is to never actually need it. Nil Einne (talk) 10:12, 8 September 2017 (UTC)

"Data" is the plural, not "datas". "Datum" is the (rarely used in this context) singular. StuRat (talk) 16:52, 8 September 2017 (UTC)

Wrong.[20] :) AQFK (talk) 16:50, 11 September 2017 (UTC)

I understand the part of overwriting files, what about folders? A file will be inserted or kept in a folder, should I overwrite a folder(s), or a file(s)? And what do you mean by "Everything since the start, so long as it hasn't been overwritten since." Let me give you an example for a better understanding for myself:

Today is the first day I bought a pendrive and used it, inserted file name "A", "B", "C", kept it for few days then deleted them all. After deletion, I inserted file name "D", "E", "F", kept it for few days then deleted them all. Will I still possess the trace of "A", "B", "C"? If yes then I'll overwrite...

How long will it take to recover data from a 16GB USB Flash drive/pendrive? Someone will give me something but desires my absence for 20-30 minutes…

The speed it takes will depend on the speed of the pen drive and what you're trying to recover. As I said above, you really should image the whole thing before doing anything in which case the time taken will at a minimum be how long it takes to read the whole drive. Also no matter a hard disk or with a USB flash drive, whether or not something will be overwritten depends entirely on the OS (or whatever is writing) and file system. Trying to predict whether it has happened is generally pointless, instead just image the drive and try to recover. A for the directory vs file point, well you're getting into the additional issue that even if the data hasn't been overwritten, the file system references may have been. More sophisticated recovery software can look for signatures for various known file types and try and recover them even if the file system reference is gone, but whether that will work, will depend again on too many things to give a general answer like how fragmented the drive was (since USB devices are still presented to the system as simple block devices), the size of the file, the type of the file, precisely what has been written where etc. Nil Einne (talk) 14:44, 9 September 2017 (UTC)

I've no idea on how to do imaging data. Could you give me a 'step by step guide' please, on how to imaging files and folders please? 103.67.156.6 (talk) 15:02, 9 September 2017 (UTC)

Sorry but if you're asking "how to imaging files and folders", you don't even understand the basics so it will take a lot of work. You may be able to find someone to help you on some forum, but I suggest you either try someone you know in real life, or just suck it up and pay someone if you're really that desperate for the data, and consider it an expensive lesson on why you should always keep lots of backups. Nil Einne (talk) 15:30, 9 September 2017 (UTC)