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TcpClient.Connect Method (String, Int32)

Connects the client to the specified port on the specified host.

Namespace:  System.Net.Sockets
Assembly:  System (in System.dll)

public void Connect(
	string hostname,
	int port


Type: System.String

The DNS name of the remote host to which you intend to connect.

Type: System.Int32

The port number of the remote host to which you intend to connect.


The hostname parameter is null.


The port parameter is not between MinPort and MaxPort.


An error occurred when accessing the socket. See the Remarks section for more information.


TcpClient is closed.

Call this method to establish a synchronous remote host connection to the specified host name and port number. The Connect method will block until it either connects or fails. After connecting with the remote host, use the GetStream method to obtain the underlying NetworkStream. Use this NetworkStream to send and receive data.

If IPv6 is enabled and the Connect(String, Int32) method is called to connect to a host that resolves to both IPv6 and IPv4 addresses, the connection to the IPv6 address will be attempted first before the IPv4 address. This may have the effect of delaying the time to establish the connection if the host is not listening on the IPv6 address.


If you receive a SocketException, use SocketException.ErrorCode to obtain the specific error code. After you have obtained this code, you can refer to the Windows Sockets version 2 API error code documentation in MSDN for a detailed description of the error.


This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.

The following code example uses the host name and port number to connect with a remote host.

//Uses a host name and port number to establish a socket connection.
TcpClient tcpClient = new TcpClient ();
tcpClient.Connect ("", 11002);
//Uses a host name and port number to establish a socket connection.
 TcpClient* tcpClient = new TcpClient();
 tcpClient->Connect(S"", 11002);

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0