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I haven been trying to understand the difference between VNC and RDP. My understanding is the VNC more or less just transmits a picture of the desktop. RDP however has more of a semantic understanding of what is happening on the desktop and transmits how to render certain types of windows, buttons, etc. (I don't know how relevant this is unless people are using Windows Presentation Foundation or something similar though...)
So it seems that RDP is a much more efficient protocol.
However, my primary use case will be for monitoring a desktop that has Chrome browser full screen. In this case, will RDP be doing the same thing as VNC would and transmitting the contents of the Chrome browser?
I think you are mostly right that RDP handles vector graphics, while vnc is mainly screen image based.
Another difference is RDP informs clients when changes occur, while VNC server waits for clients to request the screen updates. This also makes RDP more efficient.
However, as users want more and more of the same experience as the remote computer, RDP nowadays seldom send vector graphics, i.e., RDP pretty much also send screen image diffs. The reason RDP is still faster is because Microsoft has built-in drivers inside Windows to detect display changes while VNC uses workaround to do that, you can imagine Microsoft does much better job in this. So even both protocols send the same image, Microsoft is much more efficient. As a matter of fact, no Windows remoting software is as efficient as RDP (I know Citrix's ICA, let's put it under same RDP category).
If you plan to remotely use Chrome for videos, you mway feel disappointed by RDP, as it's slow unless you turn on RemoteFX, but it's only available from Windows 2008 servers (I am not sure if Windows 8 supports it, though).
So my suggestion, use RDP whenever possible.
I think you are getting confused by relating RDP and VNC with chrome. VNC (Virtual Network Computing) relates to various remote support tools like Ultra VNC, Real VNC, logmeinrescue, gosupportnow, GoToMyPC etc. and RDP means remote desktop access, remote desktop protocol, Microsoft remote desktop software etc. There are various meanings associated with RDP and VNC. It is a very detailed topic discussion of which requires lot of time.
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Im hosting my website on Github Pages with a Google Domain and on my iPhone in Chrome it works perfect
but on my desktop either Chrome(My normal Browser (i did chear cache)) or Firefox(Which i just installed) im getting the bellow error and i love some help
Thanks
Chrome Desktop
This site can’t be reached
Check if there is a typo in topher2001.com.
DNS_PROBE_FINISHED_NXDOMAIN
Firefox Desktop
Hmm. We’re having trouble finding that site.
We can’t connect to the server at topher2001.com.
Considering your site is accessible from any other PC (including mine), you should check for a local cause which would affect all your browser on your Desktop.
See for example "Firefox can't load websites but other browsers can", which lists causes like:
Internet Security software blocking Firefox
Firefox connection settings
IPv6
DNS Prefetching
Check for malware
Check if an extension is causing the problem
Some of those reason could apply to more than one browser and explain why you don't access your site on your desktop.
I was facing the same issue, it got resolved when I opened up cmd and wrote:
ipconfig/flushdns
Try anyone of these methods to solve this error.
Clear Your Browser’s Cache
Turn Off Experimental Chrome Features
Flush Your Computer’s DNS Cache
Release and Renew Your IP Address
Use Google’s Public DNS Servers
Check Your Computer’s ‘hosts’ File
100% Working Trick for chrome and other devices.
if You Host your website By using:-
1.Freenom
2.cloudflare
3.000webhost
Note:- Also recommend for all domain , hosting platform(try once) .
step1:- Download Chrome Extension VPN(Touch VPN).
step2:-After Download Restart Your Browser. Reopen.
step3:- go to extension click Touch vpn connect it to Germany.
step4:-Now, Type your Domain name in url :- example.tk etc..
BOOOM It working Fine..
Now Disconnect VPN and Try Normally to go your website..
Thank you
Blockquote
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What are the existing client-side architectures to access a local Smart Card thru a PC/SC Smart Card reader (ISO 7816-3, ISO 14443) from a generic browser (connected to a server through http(s)), preferably from Javascript, with the minimum installation hassle for the end user? The server needs to be able to at least issue APDUs of its choice to the card (or perhaps delegate some of that to client-side code that it generates). I am assuming availability on the client side of a working PC/SC stack, complete with Smart Card reader. That's a reasonable assumption at least on Windows since XP, modern OS X and Unixes.
I have so far identified the following options:
Some custom ActiveX. That's what my existing application uses (we developed it in-house), deployment is quite easy for clients with IE once they get the clearance to install the ActiveX, but it does not match the "generic browser" requirement.
Update: ActiveX is supported mostly by the deprecated IE, including IE11; but not by Edge.
Some PC/SC browser extension using the Netscape Plugin API, which seems like a smooth extension of the above. The only ready-made one I located is SConnect (webarchive). It's no longer promoted (Update: thought still actively maintained and used late 2020 in at least one application), it's API documentation (webarchive) is no longer officially available, and it has strong ties to a particular Smart Card and reader vendor. The principle may be nice, but making such a plugin for every platform would be a lot of work.
Update: NPAPI support is dropped by many browsers, including Chrome and Firefox.
A Java Applet, running on top of Oracle's JVM (1.)6 or better, which comes with javax.smartcardio. That's fine from a functional point of view, well documented, I can live with the few known bugs, but I'm afraid of an irresistible downwards spiral regarding acceptance of Java-as-a-browser-extension.
[update, Feb 2021]: This answer considered the WebUSB API as a promising solution solution in 2015, then reported in 2019 that can't work or is abandoned. I made a question about it there.
Any other idea?
Also: is there some way to prevent abuse of whatever PC/SC interface the browser has by a rogue server (e.g. presenting 3 wrong PINs to block a card, just for the nastiness of it; or making some even more evil things).
The fact is that browsers can't talk to (cryptographic) smart cards for other purposes than establishing SSL.
You shall need additional code, executed by the browser, to access smart cards.
There are tens of custom and proprietary plugins (using all three options you mentioned) for various purposes (signing being the most popular, I guess) built because there is no standard or universally accepted way, at least in Europe and I 'm sure elsewhere as well.
Creating, distributing and maintaining your own shall be a blast, because browsers release every month or so and every new release changes sanboxing ir UI tricks, so you may need to adjust your code quite often.
And you probably would want to have GUI capabilities, at least for asking the permission of the user to access a card or some functionality on it.
For creating a multiple-platform, multiple browser plugin, something like firebreath could be used.
Personally, I don't believe that exposing PC/SC to the web is any good. PC/SC is by nature qute a low level protocol that when exposing this, you could as well expose block level access to your disk and hope that "applications on the web are mine only and they behave well" (this should answer your "Also"). At the same time a thin shim like SConnect is the easiest to create, for providing a javscript plugin.sendAPDU()-style code (or just wrap all the PC/SC API and let the javascript caller take care of the same level of details as in native PC/SC API use case).
Creating a plugin for this purpose is usually driven by acute current deficiencies.
Addressing the future (mobile etc) is another story, where things like W3C webcrypto and OpenMobile API will probably finally somehow create something that exposes client-side key containers to web applications. If your target with smart cards is cryptography, my suggestion is to avoid PC/SC and use platform services (CryptoAPI on Windows, Keychain on OSX, PKCS#11 on Linux)
Any kind of design has requirements. This all applies if you're thinking of using keys rather than arbitrary APDU-s. If your requirement is to send arbitrary APDU-s, do create a plugin and just go with it.
Update (8/2016): A new API for the Web called WebUSB API is being discussed. You can already use it with Chrome v54+.
This standard will be implemented in all major browsers and will replace the need for third-party applications or extensions for Smard Cards :-)
So the new answer is YES!
And the OSI-like architecture stack is:
PC/SC
CCID v1.1
WebUSB API
USB driver, i.e. libusb.
2019 Update: As #vlp commented, it seems that it doesn't work any in Chrome because they decided to block WebUSB for smartcards for some specious reasons :-(
Note: Google annonced that they will abandon Chrome Apps in 2017.
Previous anwser:
Now (2015) you can create a Google Chrome App, using the chrome.usb API.
Then you access the smartcard reader via its CCID-compliant interface.
It's not cross-browser but JavaScript programmable & cross-platform.
Anyway Netscape Plugin API (NPAPI) is not supported any more by modern browsers. And Java applets are being dismissed by browser vendors.
I have just released a beta plugin addressing this problem.
This beta code is available here:
https://github.com/ubinity/webpcsc-firebreath
This plugin is based on the firebreath framework and has been beta-tested with Fireofx and Chrome under Linux/WinXP/Win7. Source code and extension pack are provided.
The basic idea is to provide a PCSLite API access and then develop a more friendly JS-api on top of this.
This plugin is under active development, so feel free to send any report and request.
For your first question I have little hope: either you are satisied with a very small subset of smart card functionality (like signing e-Mail or PDFs), then you may use some ready-made software (like PKCS), ideally maintained by the smart card company, or you want broader functionality and need to invest considerable effort on your own. Surely PCSC is the starting point to choose.
At least for your "also:" there is some hope.
1) Note, that some specifications (e.g. ICAO/German BSI TR-3110) request a method, where a PIN is not blocked, but uses a substantial amount of time as soon as the error counter hits 1 before replying. The final attempt must be enabled using a different command, otherwise no further comparison and error counter adjustment is done.
2) Simply protect the Verify command by requiring secure messaging. Sensitive applications use secure messaging for everything, so first step a session key is negtiated, which is second applied to all succeeding commands and responses. The effect would be, that the command is rejected due to incorrect MACs long before a comparison or modification of error counter is done.
There is another browser plugin similar to the one proposed by #cslashm available at http://github.com/cardid/WebCard. Is also open source and can be installed with "minimum installation hassle" as required in the original question. You can see an example of use visiting http://plugin.cardid.org
WebCard has been tested in IE 8 through 11, Chrome and Firefox in Windows and in Chrome and Safari in Mac OS X. Since is just a wrapper for PC/SC it requires in Mac OS X the installation of SmartCard Services from http://smartcardservices.macosforge.com
As chrome and firefox going to stop the support of NPAPI Plugin, there is no secure solution available to maintain the session for the smart card reading instead your certificate of the card have support for mutual ssl ,I answered for the similar question source,It might help
Its dirty, but if its acceptable / viable to install a bridge daemon/service on the client machine, then you can write a local bridge service (e.g. in python / pyscard) that exposes the smartcard via a REST interface, then have javascript in the browser that mediates between that local service (facade) and the remote server API.
Web Serial API (draft) can be used to communicate with a serial smart card reader from some browsers.
Buyer beware: This API is a draft and may be changed/abandoned at any time.
Speaking about Chrome, you can now use the Smart Card Connector app provided by Google which bundles the PC/SC-Lite port and the generic CCID driver.
The app itself works through the chrome.usb API, that was mentioned by the previous commenters.
So, instead of rewriting the whole stack (starting from the lowest level - raw USB), it's now possible for developers to code only the part that works on top of PC/SC API - which is exposed by the Connector app.
Clients,clients,clients...plugins,..JSApis..
Well..
For certain we know this : All browsers, when communicating to an Apache or IIS servers, are actually signing "something" when a https/SSL handshake process is needed.
For instance, a typical Apache configuration like this:
SSLVerifyClient require
SSLVerifyDepth 10
SSLOptions +FakeBasicAuth +StdEnvVars +ExportCertData +OptRenegotiate
Initiates a PIN pad pop up and the user must insert the smartcard pin to go on.
Well, my idea is : why not make the turn to the server, and tweak that behaviour, in order to upload a bytestream of stuff to sign something when a handshake is initiaded?
I have a setup where a smartcard reader is scanned to login a user. The PC/SC library work great on desktop. Somebody had mentioned to use
Emscripten (https://github.com/kripken/emscripten) compiler which compiles c++ into JavaScript code. But that didn't work well because some of the functions being used by PC/SC are only available server side.
After much research. I finally gave up on a client side solution, chrome web usb API also couldn't recognize the reader.
I then decided to give signalR a try and set up a hub on the PC connected to the smartcard reader and this approach worked out very well.
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I'd like some advice as to the best server-side code that can handle real time data from devices and make decisions based on inputs. A simple example: Suppose I have a web-enabled thermometer, running a light TCP/IP client stack. When the temperature gets to 30 degrees, I want the device to contact the server, and then I want the server to send me an email. I also want the server to be able to send a command to turn on a heater.
The issue at hand here is the ability to start a TCP message from the server, and get through an assortment of arbitrary firewalls and routers, all the way down to the client device. I know that there are 'workarounds' like polling the server for updates, or 'long polling' where I call up to the server, and keep a connection open in case it has something to send. The problem here is bandwidth. Messages are rare, but important, so the headers and handshaking make up 98% of the traffic.
I've been reading up on WebSockets, and it seems like they are exactly what I need, especially when paired with HTML5.
Does anyone know of a ready-to-go server software package that could run on a cloud server, and push data down to my devices using some standardized methods? I really don't want to reinvent the wheel here, and I can't believe I'm the first to try this. I see a few folks doing it with their own proprietary solutions, but I'm more interested in buying a one-stop package.
WebSocket is a valid choice for connecting embedded devices to backend infrastructure due to it's low overhead, low latency and compatibility with Web and general network infrastructure. There is a broad range of server implementations available, i.e. Jetty, node.js based etc.
As an example, here is a demo connecting an Arduino device to a WebSocket server and a browser client showing real-time data in a chart:
https://github.com/tavendo/AutobahnPython/tree/master/examples/wamp/serial2ws
http://www.youtube.com/watch?v=va7j86thW5M
The technology used there, AutobahnPython, is a Python/Twisted based WebSocket implementation that
provides server and client implementation
directly runs on embedded devices like RasperryPi
makes it easy to access sensors connected via serial or CANbus (since Twisted supports that very well)
provides RPC and PubSub messsaging patterns on top of WebSocket
The tech is open-source, so you can roll your own solution. If you look for help/services to get it done for you, contact me;) We also provide Tavendo WebMQ, a virtual appliance (VMware, EC2) which adds features, management UI etc and also includes a REST API to push data to WebSocket clients.
Disclaimer: I am author of Autobahn and work for Tavendo.
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I have been writing software for several decades now and these days everything is web.
Before the web we had Client Server apps that were basically thick client applications that spoke directly to the database. They had some disadvantages, such as deployment was cumbersome, Did not scale because DB handled all traffic. Of course back then distribution of apps was limited to being on a desktop on a corporate network. The benefits to these apps were that they had fewer layers and were quick to develop.
There are times when the requirements call for an app behind a firewall with a dedicated database and a relatively small amount of clients. I suggest (sometimes on StackOverflow) the old Client/Server type architecture and everybody looks at me like I have 3 legs and 6 arms.
With modern technologies that allow automatic deployments of apps and the tools we have today. Is there a reason this technology is not viable ? Is it that the new generation of developers only know web stuff ?
I can think of at least two large-ish markets where client-server is still big:
Online games and virtual worlds, such as Battlefield or Second Life. Usually you need a thick client plus a connection to a shared server.
Custom-made scientific software. Complex technical or scientific software, especially if it needs an interactive graphical UI that does direct manipulation, is sometimes written in this fashion too.
I'm sure thick clients are still being developed, even today.
Having said that, choosing a web-based architecture is not about the "new generation of developers" only knowing web stuff, you do get a lot of advantages if you can make your application web-based:
Deployment is dead simple. Even with things like ClickOnce, automatic updates, etc, nothing beats simply refreshing the page to get the latest version
You can use something like Silverlight to get 99% of the benefits of a desktop application (in terms of the ability to run code on the client)
Web applications can be made available remotely much more easily than desktop applications (a lot of companies have remote workers these days, setting up a VPN is a pain if all you want to do is access payroll (or whatever))
But at the end of the day, it's all about the right tool for the job. Web applications don't help when you want to write plugins for Office (Word, Outlook, etc), they don't help if you have to control custom hardware (POS terminals, etc - although you could write that into the server in some cases...), and probably a few more cases as well.
We have some Flex apps that communicate with XML based web services that are pretty close to old school Client Server apps. But rather than using SQL, they speak a custom XML language and render SOAP responses.
We currently develop and deploy numerous client/server applications annually. The development is simple and automated. We are not limited to the database technologies we are able to deploy. Client/server deployments are faster for calculations, form updates and reporting. The Web/Cloud based applications are less responsive than an application running on a client station (thick client).
This is because of the distribution of cpu load. Whereas a server side application requires the server to perform all calculations the client side can run this on the local machine. As any system gets more complex the moments that a user has to wait for results increases. These moments of employee time are more expensive as they involve more of the paid employees. These moments add up within an organization as a great many "man hours" over a year.
The problems with updates are solved within our development tool set. Just as when you may open your favorite browser it notices that the version you are using is not the most recent we embed that same process within our client/server applications. In fact we don't give them a choice to update. Since updates may, many times, require database changes we force the update to happen before the user is allowed to run the software.
To improve visibility of the information contained with our custom client/server systems we offer custom developed web sites that have specific applications such as field dispatch or customer support forum integration into the desktop client/server applications. From my perspective I see a complete integration of client server and responsive web applications taking a better position in the years to come.
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I want to run a website where people could see each other through web camera. I can't find anything in google, so, can you give me any suggestions or link to tutorial?
Thanks
Action Script 3 + Flash Media Server or opensource Red5 server
http://osflash.org/red5
Would like to try something hot ?
Silverlight 4 (now in Beta) seems to have support for microphone&webcam. You will need to create server side for it as well. Probably some kind of user management and contact list. There will be significant bandwidth if you get lot of users, so the server side should created be scalable to multiple machines. Maybe Azure cloud ? With any platform you choose it will take lot of effort.
I belive that you did not undestand that this think you ask, if you going to build it its takes months of design and developing.
if you search for "web chat webcam" you maybe see why I say that.
For example this http://www.ivideochat.com/ site have developed a program for that reason. See how complicate it is, how many think have.
Also you did not say, what platform you using, what is your server that going to split the video channels and send them all over the other, are you going to use it for one to one, or all to all, are you going to build it on asp.net ? on linux, on flash, on what ?
Some times small thinks in words, are too huge in developing.
So for me you must define a lot of thinks and then maybe you can see if you can do that.
1.Media stream server ? example http://www.adobe.com/products/flashmediaserver/
2.Developing platform.
3.Number of possible users.
4.The way they goint o interact each other.
5.All of them need to have camera ?
6.What about bad users (that show bad thinks) ?
7.Do they going to chat also ?
Think about all that first, then maybe is more clear to you what you going to get.
An adsl connection 12$, a computer
320$, as3 documentacion about camera
class priceless
Architecturally, you need a server to relay the video/audio to both parties, since they cannot connect directly.
You need a Silverlight or Flash 'movie' running in the browser, which you have written, and you need a server to do the relaying.
Its relatively straightforward using Haxe.
Haxe is a Free language for creating both Flash 'movies' and server applications (and more; read their homepage).
One of the Haxe-related servers that is available for Free is HaxeVideo - literally a video server that (among other things) supports live streaming from clients. Run HaxeVideo on a server and you can easily make Flash clients (written in the Haxe language naturally) do video chat.
There are several sites that do precisely this e.g. Reel Portal and DoVisio
If you anticipate a very high volume you can turn to $$$ servers such as Wowza or Flash Media Server (FMS), or you can simply add peering support to HaxeVideo.
My suggestion is to hire a developer or two who know how to build web-applications involving real-time audio & video capabilities in Flex/Silverlight.