Client - Server on Internet

Hi everybody.
I have always realized applications Client - Server. The users were using an application of windows developed in Java, which was attacking a database server, being all the users inside a local network (in the same building).
Now I have to make an application where the users (on approximately 50 in whole) are distributed by the face of the world, for what the application will have to communicate to itself across Internet.
This presents to me three doubts (possibly some of the things that I say do not have greatly sense, due to my void experience in this ambience, ask a little of comprehension before judging the post):
What type of user's interface do I use?
It might use a traditional windows application, use a web navigator, applets, html, web 2.0, javafx?.
What type of server do I use?
I do not believe that it is suitable to attack straight to the database, therefore I will have to use a server who takes charge of the business rules. What can I use? Is it possible to use hostings of third for the server (with the business rules)? Do you know anyone?
What type of comunication do I use?:
html?: web services?: others? I suppose that they will have frameworks, applications, etc. to help to develop this type of computer systems. Do you know anyone?
Since you can see, here there is many cloth. He would be grateful that you were giving me a light idea of that it could use, it would be marvelous if you can give me references (docs, you paginate webs, forums, blogs, etc) to be able to begin and study in depth the topic.
Thank you very much for your help.

TechGSis wrote:
What type of user's interface do I use?
It might use a traditional windows application, use a web navigator, applets, html, web 2.0, javafx?.
yes.
What type of server do I use?
I do not believe that it is suitable to attack straight to the database, therefore I will have to use a server who takes charge of the business rules. What can I use? Is it possible to use hostings of third for the server (with the business rules)? Do you know anyone?
That would depend on what you want the server to do of course.
What type of comunication do I use?:
html?: web services?: others? I suppose that they will have frameworks, applications, etc. to help to develop this type of computer systems. Do you know anyone?
for example.
But the only thing we can tell you is to use TCP. Whatever you send over that would depend on your decisions re clients and servers.

Similar Messages

Client Server using Internet [ask]

I have a client server project who connect between LAN connection and now I want to upgrade it into internet connection. I have search several programs who has similar architecture but none is suitable. Could anybody help me out how to build basic client server which connect using internet connection?
I have attach my previous program below, I really appreciated if anyone may modify it so be able connect trough internet.
Solved!
Go to Solution.
Attachments:
Client.vi ‏262 KB
Server.vi ‏164 KB

Hi,
with your program, you seem to have the full control over your house ;-). Why it shouldn't work over internet as it is? You have TCP open, TCP close...in Internet, you simply have to use other IP-adresses as the local ones. So can you specify your question? Or is it a problem with your LAN-infrastructure, that you have to configure your router to have access from outside?
I don't see why it shouldn't work over Inet...
christian
THINK G!! ;-)
Using LabView 2010 and 2011 on Mac and Win
Programming in Microsoft Visual C++ (Win), XCode (Mac)

SCCM MAC management server and internet Client management server in on system

dear all
we have an internet based management system (IBCM server ) sccm 2012 sp1 ,can we make the same servers as MAC management server ,is there any challenge in this ,because as per TechNet mac mangemetn server works in internet mode
even though in intranet ,also there is no documentation when mac clients are in internet
ankith

hi Torensten
we need enrolment point and enrolment proxy point can we do install in same server
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HELP:USING CLIENT SERVER PROGRAM ON DIFF.MACHINES CONNECTED TO INTERNET?

BELOW IS THE JAVA CODE FOR CLIENT & SERVER PROGRAM (TCP) USING SOCKET.
I AM TRYING TO RUN CLIENT & SERVER PROGRAM ON 2 DIFFERENT MACHINES CONNECTED 2 INTERNET
(1 RUNS SERVER.java & OTHER CLIENT.java).
IS IT POSSIBLE WITH THE CODE WRITTEN BELOW?
// Server.Java
import java.net.*;
import java.io.*;
class Server {
public static void main(String[] args) {
boolean finished = false;
try{
ServerSocket listener = new ServerSocket(4444);
while(!finished)
{Socket to_client = listener.accept();
OutputStream out = to_client.getOutputStream();
PrintWriter pout = new PrintWriter(out, true);
pout.println("Hello! this is server talking to you.");
to_client.close();
listener.close();
}// end of try
catch(Exception ie) {
System.out.println(ie);
//Client.Java
import java.net.*;
import java.io.*;
class Client
public static void main(String[] args)
Socket client;
String host="serverpcname";//host is assigned name of the server
try
{InetAddress adressen = InetAddress.getByName(host);
client = new Socket(adressen,4444);
BufferedReader scanf = new BufferedReader(new
InputStreamReader(client.getInputStream()));
String someString = scanf.readLine();
System.out.println("From Server: "+someString);
client.close();
catch(Exception e)
System.out.println(e);
WHEN THE CODE IS EXECUTED(CLIENT.java ON 1 PC & SERVER.java on other) IT GIVES FOLLOWING EXCEPTIONS:
java.net.UnknownHostException: serverpcname: serverpcname
PLZ. GUIDE ME.
THANKS IN ADVANCE.

For a server to be accessible on the inetrnet it needs to have an externally visible IP address. For example, an address which starts with 192.168.1 is for internal use only can only be used by other machines on the same internal network. The server's firewall needs to allow the port you are using access and the client has to be able to lookup up the IP address either using the hosts file or via a DNS service. None of these things have anything to do with Java programming, so if you have any more questions I sugegst you try googling them or ask a forum which relates to these issues.
The connection time out is due to the fact that there is no way to contact an inetrnal address over the inetrnet. The host unknwown means you haven't configured your PC to lookup that address. i.e. the host is unknown.

Client/server program validation - is it possible?

I've been mulling over this problem for a few days, and am starting to wonder if it's theoretically possible to find a solution. I'm not looking for specific code, this probably won't even be implemented in Java, I'm just wondering if there is a theoretical program model that would work in this situation.
The short version:
Validate the data generated by a client program, without knowing the original data.
The long version:
This is a "profiling" system for a MMOG (Massively Multiplayer Online Game). The MMOG is an internet based client/server graphical program where each client connects to the server and they interact with each other and the virtual world. They pay a monthly fee for access to the game. My program is not affiliated with the MMOG or its makers. I have no connections inside the company and cannot expect any cooperation from them.
The "profiling" system is also a client/server model. The client program runs in the background while the MMOG client is active. It accesses the memory of the MMOG client to retrieve information about the player's character. Then, possibly on request or maybe immediately, it sends the character data to our server.
What I want to validate is that the character data being sent is unmodified and actually comes from the MMOG program.
I can reasonably expect that with mild encryption and some sort of checksum or digest, the vast majority of problems can be avoided. However, I am not sure it's possible to completely secure the system.
I assume that the user has access to and knowledge of the profiler client and the MMOG client, their assembly code, and the ability to modify them or create new programs, leveraging that knowledge. I also assume that the user does not have access to or knowledge of either of the server applications - the MMOG server or mine.
In a worst-case scenario, there are several ways they could circumvent any security I have yet been able to think of. For instance, they could set up a fake MMOG client that had the data they wanted in memory, and let the profiler access that instead of the real thing. Or, they could rewrite the profiler to use the data they wanted and still encrypt it using whatever format I had specified.
I have been considering using some kind of buffer overflow vulnerability or remote execution technique that would allow me to run specific parts of the client program on command, or get information by request, something that could not be anticipated prior to execution and thus could not be faked. But this seems not only insecure for the client but also not quite solid enough, depending on how it was implemented.
Perhaps a series of apparently random validation codes, where the client does not know which one actually is doing the validation, so it must honor them all. Again, this is very conceptual and I'm sure that I'm not explaining them very well. I'm open to ideas.
If I don't come up with anything better, I would consider relying on human error and the fact that the user will not know, at first, the relevance of some of the data being passed between client and server. In this case, I would include some kind of "security handshake" that looks like garbage to the client but actually is validated on the server end. A modified program or data file would result in an invalid handshake, alerting the server (and me) that this client was a potential problem. The client would have no idea anything had gone wrong, because they would not know what data the server was expecting to receive.
I hope I have not confused anyone too much. I know I've confused myself....

Yes, that is the general model for all MMOGs these days - no data that can actually affect the game is safe if loaded from the client's computer. All character and world data is sent from server to client and stored in memory. Any information that is saved to the client's computer is for reference only and not used by the game engine to determine the results of actions/events etc.
My program accesses the MMOG client's memory while the game is running, and takes the character information from there. It does not have direct access to the MMOG server, and does not attempt to modify the data or the memory. Instead, it just encrypts it and sends it to our server, where the information is loaded into a database.
The security issue comes into play because our database is used for ranking purposes, and if someone were to hack my program, they could send invalid data to our servers and affect the rankings unfairly.
I'm just trying to think of a way to prevent that from happening.

VPN Site-to-Site or VPN Client Server with Cisco IP Phone 8941 and 8945

Hi everyone,
I decide to deploy a CUCM (BE6K platform), SX20, and IP Phone 8941/8945 on Head Office and Cisco SX10 and IP Phone 8941/8945 for branch offices (actually 9 branch offices).
The connection will use internet connection for HO and each branch offices.
And the IT guy want to use kind a VPN client server or VPN site-to-site for the connection through internet,
what kind of VPN client server or VPN site-to-site that recommended for this deployment?
and what type of Cisco router that support that kind of VPN (the cheapest one will be great)?
So the SX10 and IP Phone 8941/8945 in branch offices can work properly through internet connection?
please advise
Regards,
Ovindo

Hi Leo,
technically, the ipsec users will not use up any premium license seats, so if you have 10 ipsec users connecting first, the premium seats are still free and so you can then still have 10 phones/anyconnect users connect.
However, the 250 you mention is the global platform limit, so it refers to the sum of premium and non-premium connections. Or in other words, you can have 240 ipsec users and 10 phones, but not 250 ipsec users and 10 phones.
If 250 ipsec users and 10 phones would try to connect, it would be first-in, first-served, e.g. you could have 248 ipsec users and 2 phones connected.
Note: since you have Essentials disabled I'm assuming you are referring to the legacy "Cisco vpnclient" (IKEv1 client) which does not require any license on the ASA. But for the benefit of others reading this thread: if you do have Anyconnect clients (using SSL or IPsec/IKEv2) for which you currently have an Essentials license, then note that the Essentials and Premium license cannot co-exist. So for e.g. 240 Anyconnect users and no phones, you can use Essentials. For 240 Anyconnect users and 10 phones, you need a 250-seat Premium license (and a vpn phone license).
hth
Herbert

Client dns and internet connection

Hi,
Running 10.5.5 Server with basic DNS for inter clients to access AFP/SMB and Wiki services via Open Directory. IP address is 192.168.1.10
Clients currently receive internet via DHCP from a router and Network preferences autofills DNS and search domains with router address 192.168.1.1 and RP614v4 respectively.
If I add the server IP and search domain, I can't see the server via DNS name unless I reverse the order in the fields (192.168.1.10 and ######.private). However this turns the internet connection to snail pace.
How can I get the DNS to work for both the internal server and internet connection?
Thanks,
Joel.

If your DNS server is running correctly, there's no reason why it should resolve any slower than the router. The fact you're mentioning it implies that the delay is significant so I'll guess that your clients are requesting an address from your server, but that's timing out so they're falling back to the router before proceeding.
You should check your DNS server to make sure it's set to be recursive (so it answers queries for non-local domains, too). That way the clients can get all lookups from your server and you should be good to go.

Mac mini server how many clients serve same time

mac mini server[lion server] how many clients serve same time, the web server, suppose only traffic the web server?
macs/PCs with server OSs designed for work as normal, but more mainly for left on, connected and serve clients on the internet eg web server, mail server? T/F

Thanks for your help. I actually forgot that I posted this and when I saw the email telling me you sent a repsonse I then did another search (using a different phrase) and I found this:
https://discussions.apple.com/thread/4554036?start=0&tstart=0
I think that is saying that I can do what I am asking.

Servlet in client/server application?

hi,
I am planing to make a client server application( SWING & an OODB), would it be clever to use servlet ( not httpservlet) as midle tier framework?
If yes , what are the benefits?
Thanks.

thanks for responding
actually my client don't wanna run a separate server application on the hosting machine as it costs too much, so thats why i think there is no other way to achieve the task rather than using servlets.
please do help me or atleast give me a suggestion. actually i'm developing an internet messenger application. i have developed it using client/server application model in which both (the swing client and the server) uses java sockets to communicate with each other. but now i want to develop the server side of the messenger as servlets. but as far as i know the servlets follow the request/response model. if i follow that model i have to use some sort of client pull after certain amount of time say after five or ten seconds, and this approach does not fulfill my requirements as it would slow the performance if there are hundreds of clients calling the servlet every 5 seconds. thus i want to create persisted connections between the client and the servlet which last for the life time of the user's session. also it is important for the data integrity of the application, so please help me in this matter as i have no other source of guidence in this meany world. i hope you will certainely help me in this matter. please mention that if there are any drawbacks of my approach i mean the persisted connections.
thanks you a lot
Best reagrds
Imran Sarwar.

Incorrect decryption operation in client-server

Hi all, sorry for my English, I don't know where is the problem and I don't see examples for internet.
I have a cliente-server aplication, where client read a file, encrypt it and send it to server. The server doesn't decrypt de text correcty. For example if the file contents:
"Hola, probando el cifrado y descifrado.", the server shows "Hola, probando eifrado."
I think that the problem is in the form for send and receive the cipher text.
I put the code for client:
import java.net.*;
import java.io.*;
import java.security.*;
import javax.crypto.*;
class ClientAES {
public static void main(String argv[]) {
    try {
      System.out.print("Introduce the key : ");
      String cadena = Teclado.readString();
      SecureRandom rand = new SecureRandom(cadena.getBytes());
      System.out.println("Generating key...");
      KeyGenerator keyGen = KeyGenerator.getInstance("AES");
      keyGen.init(rand);
      SecretKey desKey = keyGen.generateKey();
      System.out.println("Key generated");
      Socket s=new Socket(argv[0],4096);
      FileInputStream fis = new FileInputStream(argv[1]);
      byte[] b=new byte[fis.available()];
      System.out.println("Bytes that can be read of file: "+fis.available());
      fis.read(b);
      System.out.println(Text send: "+new String(b));
      Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
      cipher.init(cipher.ENCRYPT_MODE,desKey);
      CipherOutputStream cos = new CipherOutputStream(s.getOutputStream(), cipher);
      cos.write(b, 0, b.length);
      fis.close();
      cos.close();
      s.close();
    } catch (Exception e) { e.printStackTrace(); }
}and server:
import java.net.*;
import java.io.*;
import java.security.*;
import javax.crypto.*;
class ServerAES {
public static void main(String argv[]) {
    try {
      System.out.print("Introduce the key: ");
      String cadena = Teclado.readString();
      SecureRandom rand = new SecureRandom(cadena.getBytes());
      System.out.println("Generating key...");
      KeyGenerator keyGen = KeyGenerator.getInstance("AES");
      keyGen.init(rand);
      SecretKey desKey = keyGen.generateKey();
      System.out.println("Key generated");
      ServerSocket servidor=new ServerSocket(4096);
      System.out.println("Waiting a client...");
      Socket s=servidor.accept();
      System.out.println("Recieve a client connection");
      Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
      cipher.init(cipher.DECRYPT_MODE,desKey);
      CipherInputStream cis = new CipherInputStream(s.getInputStream(), cipher);
      byte[] in = new byte[cipher.getBlockSize()];
      int length;
      System.out.println(cipher.getBlockSize());
       length = cis.read(in, 0, in.length);
      System.out.println(new String(in)+new String(cipher.doFinal()));
      cis.close();
      s.close();
    } catch (Exception e) { e.printStackTrace(); }
}

eeeh, if I understand your code correctly, then you are creating keys in each process. That means, you'll have two different keys. But you are using AES, which is a symmetric encryption algorithm. Hence you'll need to have the same key on both sides. Otherwise you'll not decrypting the stuff you where encrypting before.
stephan

Calling Web Form from Client-Server Form

Hi. I have an existing Client-Server Form (6i) still in production that needs to call a Web Form and pass it a parameter. Obviously I can't use Call Form or New Form from the client-server version, but can I somehow issue a command line (including a parameter) that opens the Web Form? Any suggestions for accomplishing this?
I can create a command line like this, but have no idea how to pass a parameter to my Web Form. The Web Form named participants which has a Parameter defined named 'p_participant'.
*"C:\Program Files\Internet Explorer\iexplore.exe" http://9.35.32.206:7777/forms/frmservlet?form=participants*
I can also create a command line to open a web form like this to:
*"C:\Program Files\Internet Explorer\iexplore.exe" http://9.35.32.205:7777/forms/html/sas2.htm*
Where the sas2.htm looks like this:
*<html>*
*<body onload="document.menulaunch.submit();">*
Launching File Generation...
If the application does not load in 30 seconds then click the button below:
*<form name=menulaunch action=http://9.35.32.205:7777/forms/frmservlet?config=FileGeneration method=post>*
*<script>*
var wshshell=new ActiveXObject("wscript.shell");
var username=wshshell.ExpandEnvironmentStrings("%orauser%");
var pw=wshshell.ExpandEnvironmentStrings("%orapass%");
document.write("<input type=hidden name=userid value="+username+"/"+pw+"@sparc20*>")*
*</script>*
*<input type=submit value=Launch>*
*</form>*
*</body>*
*</html>*
Any help would be greatly appreciated.
Edited by: Buechler on Apr 8, 2009 8:58 AM

Simply add to your URL as follows:
http://9.35.32.206:7777/forms/frmservlet?form=participants&otherparams=p_participant=<SOME VALUE>I assume you plan to use HOST to make this call. I would recommend something like this:
HOST ('cmd /c start iexplore.exe "http://9.35.32.206:7777/forms/frmservlet?form=participants&otherparams=p_participant=<SOME VALUE>"');

Small client server project. deisgn idea good or bad?

Hi,
I have a question:
I have this plan to make a small Swing based GUI on the client machine (that I would like a novice user to be able to double click on to launch) which needs to connect to a Server side component , I am thinking a simple Servlet or JSP page. Then what needs to happen is a few messages are transferred to ascertain the users identity for authenitcation as so:
1. Client -> Server 2. Server -> Client 3. Client -> Server. Access gratned or not for access to restricted web page (imagine inbox e-banking etc)
So the main questions are:
1. Can I make a small Swing based GUI App, NOT an applet as I need to read from the client, that can be easily launched by an idiot ;)
2. Can that small app converse with a Servlet in the manner described above.
3. Kinda like 2. Can the Client App launch a browser window to that when the messages are done the user can then get into the area the server has granted them access to (depending on the messages).
I would really appriciate the help. I have looked about on the internet and in books but I never really got a succinct picture this would be possible.
Thanks!

I have this plan to make a small Swing based GUI on
the client machine (that I would like a novice user
to be able to double click on to launch) which needs
to connect to a Server side component , I am thinking
a simple Servlet or JSP page. That will involve writing an applet.
1. Can I make a small Swing based GUI App, I don't know if you can or not! It's certainly possible...
NOT an applet See above.
as I need to read from the client, That's not a restriction. You can sign your applets.
that can be easily launched by an idiot ;) Once again, that's up to you.
2. Can that small app converse with a Servlet in the
manner described above.Yes.
3. Kinda like 2. Can the Client App launch a browser
window to that when the messages are done the user
can then get into the area the server has granted
them access to (depending on the messages).Yes.
I would really appriciate the help. I have looked
about on the internet and in books but I never really
got a succinct picture this would be possible.It is! Good luck, and happy coding! If you need some resources, check out the following:
The Java� Tutorial - Trail: Creating a GUI with JFC/Swing
The Java� Tutorial - Trail: Writing Applets
Trail: Getting Started - Lesson: The Anatomy of an Applet
Java Applet Tutorials
The Java� Tutorial - I/O: Reading and Writing (but no 'rithmetic)

JMF - client server video streaming how to stop

Hi
I am able to stream video from a server to multiple clients using AVReceive2 and AVTransmit2 from the JMF site.
Iam developing a client server project. I have modified the above code such that Iam able to start and stream the videos by calling on servlets and socket connections.
The AVTransmit2 code does not however have a stop button and it uses a thread.sleep method. I do not know how to add a stop button in the GUI on AVReceive2 to call on AVTransmit2.
I am using sockets to communicate to and from the server. Do i have to use RMI or is there another easier way to call stop from the client which would stop the transmission on the server?
Also, after the video file has been successfully streamed, when I refresh and try to connect again, the server is invoked and __it starts transmission_,_ but the servlet which calls the AVReceive fails and the frame does not show. Any possible reasons why?
Thanks in advance.
Junior

I don't know the speed of the connection.
4-10 users usually.
.11b or .11g I don't know.
microwave nearby - I don't know
5-6 other wifis - yes
I will try Safari, thanks!
Thanks for the update. The speed of the Wi-Fi in the
coffee shop will depend on many factors. What is the
speed of their connection to the Internet? How many
people are sharing the Wi-Fi? Is it 802.11b or
802.11g? Do they have a microwave operating nearby?
That will often interfere. Are there additional Wi-Fi
networks nearby? That can interfere as well. It's
possible that it was their network that's causing
your trouble. But, to rule that out, did you try
using Safari instead? You might make sure you have an
up-to-date version of the Flash player which you can
get at http://www.adobe.com
I have Clearwire
at home, it's basically like wireless DSL. It's not
as fast as cable Internet access, but it is portable.
I only mentioned it because it would indicate that
you don't need cable speed to watch the videos
without buffering.
-Doug

How long is it to implement JSSE on a client-server architecture?

Hi all of you,
Since I'm not a developper but more a system admin, I'm wondering how long approximatly it would take to adapt an existing JAVA client-server architecture to use JSSE or SSL communication over the internet. Is it a simple task or are we talking about weeks of work? Where would be installed the SSL certificate, on the web server or the database server? In brief, what are the main steps that a developper has to go through?
Architecture:
JAVA client
Web server (RMI server), Microsoft IIS5.0
Database server (MySQL4.0)
Thanks you all for your precious time,
AD

If your webserver has a server certificate from one of the "Big Boys" in the CA business, and if you don't need client-authentication (and almost no-one does) - in your client, write "SSL" in front of everywhere the app currently has the word "Socket", and scratch out "HttpUrl" and replace it with HttpsUrl,." and change your access-urls to start with "https:" and change your socket-connections to talk to your server's SSL port, and you're done. I've taken a Socket-based app and made it SSL/Plain bilingual in two hours once (admittedly, it was a small and well-designed app).
If your server-cert isn't signed by a known CA, then you have to play some games to get the client side to accept it - but they've all been discussed to death in this forum.
Grant

Capturing SQLNET client-server traffic

Pardon the somewhat newbie-like question ...
I am trying to build a API test stub where I need to be able to capture the requests and responses between third-party two-tier applications then replay the traffic. The replay is easy. The capture, though, is giving me trouble.
For HTTP traffic, it is easy. I just change Internet Explore's HTTP port address to point to a fake proxy which records the requests the sends the requests onto the real web server.
Is there an equivalent to this in the SQLNET world? I am hoping that a proxy already exists to do this.
If not, is there a way to turn on a full trace for a specific client? I would need to capture all connections coming out of the client and no other client's connections.

This could provoke quite a discussion.
"If your client are on slow links you may, for example query 10,000 rows of data. "
Generally, forms shouldn't be pulling back tens of thousands of rows from the database. Your user is unlikely to page through that much, so either you want a summary (which is best calculated on the database server and the summary results dragged across the network) or you are paging through records in the tens, not tens of thousands. (Look at the 'Number of recods buffered' property in your base table blocks. Bet it's one or two digits, not five!)
"The information that is transmitted to the client is basically screen draw information - and this will be alot less than the 10,000 rows you were querying before. "
As above. In client/server you shouldn't have been bringing stuff from the database down to the client that wasn't going to be on the screen anyway, especially if you had a slow network.
Depending on how your application is written, it could well peform a lot worse on the web than in client server. Rather than having the client do a fair share of the work, it's now got to keep talking to the application server to get anything done.
For example, because navigation triggers don't allow the use of restricted built-ins, rather than putting code in a 'post-text-item/when-validate-item' trigger on the relevant item, it gets put in a form level 'when-new-item-instance' trigger. It's a bit untidy in client/server but workable. Put it on the web, and every time the user tabs between fields, the form has to go off to the application server to fire the when-new-item-intance trigger to tell it what to do next.
Another 'speed-bump' is if you have any synchronize bits (eg in a post-query trigger, or as part of a "I'm 10% complete" information messages in long running loops). These will also generate network traffic between the app server and form.
While web server does have advantages, I wouldn't be selling it on it's performance improvements.

Client - Server on Internet

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