Automatic Connection

API

Tip: For detailed documentation refer to the IntelliSense tips that appear when you call a given API method.

• AutoConnect() - Automatically discover working FTP connection settings and use those to connect to the server. This method will intelligently try certain combinations of connection settings until it finds a working combination. The connection types are tried in this order of preference.

• AutoDetect() - Automatically discover working FTP connection settings and return those connection profiles. This method will intelligently try certain combinations of connection settings until it finds a working combination, and it will return the first found combination or all found combinations. The connection types are tried in this order of preference.

How do I auto-connect to an FTP or FTPS server?

Use this code:

FtpClient client = new FtpClient(hostname, username, password); // or set Host & Credentials
client.AutoConnect();

How do I auto-detect the correct connection settings?

Use this code:

FtpClient client = new FtpClient(hostname, username, password); // or set Host & Credentials
var profiles = client.AutoDetect();

// if any profiles are found, print the code to the console
if (profiles.Count > 0){
	var code = profiles[0].ToCode();
	Console.WriteLine(code);
}

Once you find a working connection profile, use the generated code to quickly connect to your FTP server.

In what order of preference does an auto connection follow?

Auto connection attempts to find working connection settings in this order of preference:

Protocol Preference:

1. Explicit FTPS (TLS) - very common
2. Plaintext FTP - very common
3. Implicit FTPS (SSL) - outdated and very rare

FTPS Protocol Preference:

2. Tls12 | Tls11 - TLS 1.2 or TLS 1.1 (TLS 1.3 is not yet stable in .NET Framework)
3. Tls - TLS 1.0
4. Default - Undefined/weird behaviour

Data Connection Type Preference:

• For servers connected over IPV6, we use EPSV (enhanced passive)
• For servers connected over IPV4, we try PASV (passive) which has the widest support on FTP servers

Encoding Type Preference:

• UTF8 - We always use Unicode if it can be supported by the server

What properties does an auto connection generate?

Auto connection automatically calculates the best values for the following properties in FtpClient:

1. Port (unless a non-standard port is specified before calling AutoConnect)
2. EncryptionMode
3. SslProtocols
4. DataConnectionType
5. Encoding