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An FTP secure client library for C#

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10 Dec 2008CPOL2 min read 489.5K   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

 
QuestionExplicit FTP over TLS Pin
SoftEnd9-Jun-16 21:20
professionalSoftEnd9-Jun-16 21:20 
Question_sslStream.AuthenticateAsClient hangout Pin
Salar IB14-Mar-15 7:07
Salar IB14-Mar-15 7:07 
AnswerRe: _sslStream.AuthenticateAsClient hangout Pin
ravit2326-Mar-18 0:22
ravit2326-Mar-18 0:22 
QuestionException Pin
MehraRaj25-Dec-14 18:01
MehraRaj25-Dec-14 18:01 
GeneralBeware and use with caution Pin
Seva Zaslavsky11-Jul-14 2:03
Seva Zaslavsky11-Jul-14 2:03 
GeneralRe: Beware and use with caution Pin
Antonio Ripa1-Aug-14 11:05
professionalAntonio Ripa1-Aug-14 11:05 
SuggestionAnother library to try if you have problems with this one.... Pin
gmagana29-Jan-14 13:37
gmagana29-Jan-14 13:37 
QuestionAplication freezing after login method Pin
Leo Fraietta14-Jan-14 8:45
Leo Fraietta14-Jan-14 8:45 
Questionsftp Pin
King Ravi Kumar 14-May-13 2:13
King Ravi Kumar 14-May-13 2:13 
QuestionDoes anyone have an implemenation example ? Pin
Member 979519322-Mar-13 8:24
Member 979519322-Mar-13 8:24 
QuestionAn unknown, invalid, or unsupported option or level was specified in a getsockopt or setsockopt call Pin
Member 982113318-Feb-13 8:26
Member 982113318-Feb-13 8:26 
QuestionHow to run this program. Pin
Member 982113318-Feb-13 8:05
Member 982113318-Feb-13 8:05 
QuestionFTPS - Connecting to the server through proxy Pin
Member 251419017-Jan-13 21:19
Member 251419017-Jan-13 21:19 
QuestionWhy is the SslStream object stuff commented out? Is this truly FTP over SSL without that? Pin
andegre16-Aug-12 8:31
andegre16-Aug-12 8:31 
QuestionDir not working with secure Pin
eyedia30-May-12 7:47
eyedia30-May-12 7:47 
AnswerAre you having issues uploading and downloading files? Pin
Member 76555695-Apr-12 11:09
Member 76555695-Apr-12 11:09 
GeneralRe: Are you having issues uploading and downloading files? Pin
gmagana29-Jan-14 11:26
gmagana29-Jan-14 11:26 
QuestionIndex and length must refer to a location within the string.\r\nParameter name: length Pin
Member 84911326-Mar-12 21:56
Member 84911326-Mar-12 21:56 
QuestionNo port 990 Pin
Member 855570311-Jan-12 7:02
Member 855570311-Jan-12 7:02 
AnswerRe: No port 990 Pin
bob mourning2-Mar-12 2:49
bob mourning2-Mar-12 2:49 
Questionneeds your helps Pin
Jacob P Yamarthi18-Oct-11 21:53
Jacob P Yamarthi18-Oct-11 21:53 
AnswerRe: needs your helps Pin
Member 76555695-Apr-12 10:57
Member 76555695-Apr-12 10:57 
GeneralRe: needs your helps Pin
volax12-Feb-13 5:39
volax12-Feb-13 5:39 
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 

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