Hello, About KeepAlive, here is what I found in a old TCP-IP NT5.0 white paper from Microsoft.
TCP Keep-alive Messages A TCP keep-alive packet is simply an ACK with the sequence number set to one less than the current sequence number for the connection. A host receiving one of these ACKs will respond with an ACK for the current sequence number. Keep-alives can be used to verify that the computer at the remote end of a connection is still available. TCP keep-alives can be sent once every KeepAliveTime (defaults to 7,200,000 milliseconds or two hours), if no other data or higher level keep-alives have been carried over the TCP connection. If there is no response to a keep-alive, it is repeated once every KeepAliveInterval seconds. KeepAliveInterval defaults to 1 second. NetBT connections, such as those used by many Microsoft networking components, send NetBIOS keep-alives more frequently, so normally no TCP keep-alives will be sent on a NetBIOS connection. TCP keep-alives are disabled by default, but Windows Sockets applications can use the SetSockOpt function to enable them. Registry key start from : HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ KeepAliveInterval Key: Tcpip\Parameters Value Type: REG_DWORD-Time in milliseconds Valid Range: 1-0xFFFFFFFF Default: 1000 (one second) Description: This parameter determines the interval between keep-alive retransmissions until a response is received. Once a response is received, the delay until the next keep-alive transmission is again controlled by the value of KeepAliveTime. The connection will be aborted after the number of retransmissions specified by TcpMaxDataRetransmissions have gone unanswered. KeepAliveTime Key: Tcpip\Parameters Value Type: REG_DWORD-Time in milliseconds Valid Range: 1-0xFFFFFFFF Default: 7,200,000 (two hours) Description: The parameter controls how often TCP attempts to verify that an idle connection is still intact by sending a keep-alive packet. If the remote system is still reachable and functioning, it will acknowledge the keep-alive transmission. Keep-alive packets are not sent by default. This feature may be enabled on a connection by an application. -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
