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An FTP secure client library for C#

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10 Dec 2008CPOL2 min read 490K   15.8K   135   106
How to implement an FTP secure connection with an SSL stream class.

Introduction

The purpose of this article is to create a C # FTP client in Secure mode, so if you don’t have much knowledge of FTPS, I advise you to take a look at this: FTPS.

In the .NET Framework, to upload a file in FTPS mode, we generally use the FtpWebRequest class, but you can not send commands with « quote » arguments, and even if you search on the web, you will not find a concrete example of a secured C# FTP client.

It’s for those reasons I decided to create this article.

SSL Stream?

To send a socket in Secure Socket Layer (SSL) mode, we use the class System.Net.Security.SslStream.

Provides a stream used for client-server communication that uses the Secure Socket Layer (SSL) security protocol to authenticate the server and optionally the client”.

For more information, refer to MSDN.

Using the Code

1. Pre-Authenticate

C#
FTPFactory ftp = new FTPFactory();
ftp.setDebug(true);
ftp.setRemoteHost(Settings.Default.TargetFtpSource);

//Connect to SSL Port (990)
ftp.setRemotePort(990);
ftp.loginWithoutUser();

//Send "AUTH SSL" Command
string cmd = "AUTH SSL";
ftp.sendCommand(cmd);

Before connecting to the FTP server in SSL mode, you have to define the 990 SSL port and send the « AUTH SSL » command authentication using SSL.

WelcomeFTPSecure.JPG

2. Create SSL Stream

C#
//Create SSL Stream
ftp.getSslStream();
ftp.setUseStream(true);
//Login to FTP Secure
ftp.setRemoteUser(Settings.Default.TargetFtpSecureUser);
ftp.setRemotePass(Settings.Default.TargetFtpSecurePass);
ftp.login();

ftp.getSslStream() creates an SSL stream from client socket which will be used for exchange between the client and the server FTPS. Then, you have to enter a login and password to authenticate on the FTPS server.

Note: if the SSL stream is well established, then I display all the information about the server certificate.

CertificatInfos.JPG

3. Upload File

C#
//Set ASCII Mode
ftp.setBinaryMode(false);

//Send Arguments if you want
//cmd = "site arg1 arg2";
//ftp.sendCommand(cmd);

//Upload file
ftp.uploadSecure(@"Filepath", false);

ftp.close();

Before uploading a file, you have to specify the mode: ftp.setBinaryMode(bool value).

  • value is false --> ASCII mode
  • value is true --> Binary mode

By default, it’s binary. Now, you upload the file using:

C#
ftp.uploadSecure(@"Filepath", false)

Note: you can upload in non secured mode using ftp.upload().

Points of Interest

I learned how an SSL stream and the RAW FTP communication works between a client and an FTP server. Searching on the web, I found many who were stuck on the issue of SSL communication with an FTP server, so I hope this article will be of great help.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


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Comments and Discussions

 
QuestionUpload File - Nothing Happens Pin
Sergio Marchetti22-Aug-11 12:04
Sergio Marchetti22-Aug-11 12:04 
AnswerRe: Upload File - Nothing Happens Pin
Member 76555695-Apr-12 10:56
Member 76555695-Apr-12 10:56 
QuestionCannot Upload File Pin
luis hernandez11-Aug-11 9:20
luis hernandez11-Aug-11 9:20 
AnswerRe: Cannot Upload File Pin
Member 76555695-Apr-12 10:56
Member 76555695-Apr-12 10:56 
QuestionError: A non-blocking socket operation could not be completed immediately Pin
bigMoey27-Jun-11 18:29
bigMoey27-Jun-11 18:29 
GeneralI can not run this project. Pin
wertyk12-May-11 3:16
wertyk12-May-11 3:16 
GeneralRe: I can not run this project. Pin
kadaoui el mehdi12-May-11 6:24
kadaoui el mehdi12-May-11 6:24 
GeneralRe: I can not run this project. Pin
wertyk12-May-11 20:25
wertyk12-May-11 20:25 
GeneralRe: I can not run this project. Pin
kadaoui el mehdi12-May-11 21:58
kadaoui el mehdi12-May-11 21:58 
QuestionError on ftp.loginWihtoutUser Pin
jayson pryde28-Oct-10 11:45
jayson pryde28-Oct-10 11:45 
AnswerRe: Error on ftp.loginWihtoutUser Pin
gyingLiow9-Apr-13 20:15
gyingLiow9-Apr-13 20:15 
GeneralOriginal FTPFactory.cs written by Jaimon Mathew. PinPopular
JulianPo23-Nov-09 5:40
JulianPo23-Nov-09 5:40 
General"An existing connection was forcibly closed by the remote host." [modified] Pin
Hoang dinh Trung18-Nov-09 21:43
Hoang dinh Trung18-Nov-09 21:43 
GeneralRe: "An existing connection was forcibly closed by the remote host." Pin
kadaoui el mehdi19-Nov-09 1:06
kadaoui el mehdi19-Nov-09 1:06 
GeneralRe: "An existing connection was forcibly closed by the remote host." Pin
Hoang dinh Trung19-Nov-09 19:37
Hoang dinh Trung19-Nov-09 19:37 
GeneralRe: "An existing connection was forcibly closed by the remote host." Pin
kadaoui el mehdi19-Nov-09 20:43
kadaoui el mehdi19-Nov-09 20:43 
GeneralRe: "An existing connection was forcibly closed by the remote host." Pin
Hoang dinh Trung21-Nov-09 4:21
Hoang dinh Trung21-Nov-09 4:21 
GeneralRe: "An existing connection was forcibly closed by the remote host." Pin
kadaoui el mehdi24-Nov-09 21:02
kadaoui el mehdi24-Nov-09 21:02 
GeneralRe: "An existing connection was forcibly closed by the remote host." Pin
mdbaskaran30-Dec-09 9:55
mdbaskaran30-Dec-09 9:55 
GeneralRe: "An existing connection was forcibly closed by the remote host." Pin
SonnyDude13-Jul-10 21:11
SonnyDude13-Jul-10 21:11 
GeneralGetting a file listing returning odd characters Pin
hankgrav16-Nov-09 7:40
hankgrav16-Nov-09 7:40 
GeneralRe: Getting a file listing returning odd characters Pin
kadaoui el mehdi16-Nov-09 9:20
kadaoui el mehdi16-Nov-09 9:20 
GeneralRe: Getting a file listing returning odd characters Pin
hankgrav16-Nov-09 9:26
hankgrav16-Nov-09 9:26 
GeneralRe: Getting a file listing returning odd characters Pin
kadaoui el mehdi16-Nov-09 9:47
kadaoui el mehdi16-Nov-09 9:47 
GeneralRe: Getting a file listing returning odd characters Pin
hankgrav16-Nov-09 9:56
hankgrav16-Nov-09 9:56 

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