Export (0) Print
Expand All

TcpState Enumeration

Specifies the states of a Transmission Control Protocol (TCP) connection.

Namespace: System.Net.NetworkInformation
Assembly: System (in system.dll)

public enum TcpState
public enum TcpState
public enum TcpState

 Member nameDescription
ClosedThe TCP connection is closed. 
CloseWaitThe local endpoint of the TCP connection is waiting for a connection termination request from the local user. 
ClosingThe local endpoint of the TCP connection is waiting for an acknowledgement of the connection termination request sent previously. 
DeleteTcbThe transmission control buffer (TCB) for the TCP connection is being deleted. 
EstablishedThe TCP handshake is complete. The connection has been established and data can be sent. 
FinWait1The local endpoint of the TCP connection is waiting for a connection termination request from the remote endpoint or for an acknowledgement of the connection termination request sent previously. 
FinWait2The local endpoint of the TCP connection is waiting for a connection termination request from the remote endpoint. 
LastAckThe local endpoint of the TCP connection is waiting for the final acknowledgement of the connection termination request sent previously. 
ListenThe local endpoint of the TCP connection is listening for a connection request from any remote endpoint. 
SynReceivedThe local endpoint of the TCP connection has sent and received a connection request and is waiting for an acknowledgment. 
SynSentThe local endpoint of the TCP connection has sent the remote endpoint a segment header with the synchronize (SYN) control bit set and is waiting for a matching connection request. 
TimeWaitThe local endpoint of the TCP connection is waiting for enough time to pass to ensure that the remote endpoint received the acknowledgement of its connection termination request. 
UnknownThe TCP connection state is unknown. 

This enumeration defines valid values for the State property. TCP is a transport layer protocol responsible for reliably sending and receiving data packets. The TCP states in this enumeration are defined in IETF RFC 793 available at http://www.ietf.org.

The following code example counts the established TCP connections.

public static void CountTcpConnections()
{
    IPGlobalProperties properties = IPGlobalProperties.GetIPGlobalProperties();
    TcpConnectionInformation[] connections = properties.GetActiveTcpConnections();
    int establishedConnections = 0;
    
    foreach (TcpConnectionInformation t in connections)
    {
        if (t.State == TcpState.Established)
        {
             establishedConnections++;
        }
        Console.Write("Local endpoint: {0} ",t.LocalEndPoint.Address);
        Console.WriteLine("Remote endpoint: {0} ",t.RemoteEndPoint.Address);
       
    }
     Console.WriteLine("There are {0} established TCP connections.",
        establishedConnections);
}

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

Community Additions

ADD
Show:
© 2014 Microsoft