Does anyone know how to set the TCP/IP abort interval or timeout in Windows XP?

In my machine, when I open in IE, Firefox, or Google Chrome, it will cost about 20 seconds to abort, it's too long to wait, I want to adjust the TCP/IP abort interval to 10 seconds.

I've tried the TcpMaxDataRetransmissions, TcpMaxConnectRetransmissions in regedit, it does not work.

  • Finnaly, i found that setting TcpMaxConnectRetransmissions=1 makes the timeout became to 10 senconds, i don't understand why.
    – diyism
    Jun 22, 2011 at 9:54

1 Answer 1


Have a look at TCP Retransmission Behavior article on the MSDN site:

A number of registry values under the HKEY_LOCAL_MACHINE\System\CurrentControlSetServices\Tcpip\Parameters registry key adjust the behavior of TCP retransmission:

The per-adapter value TcpInitialRtt controls the retransmission timer. This timer identifies the number of milliseconds to wait for an acknowledgment after the first transmission of a segment before retransmitting it.

The TcpMaxConnectRetransmissions value indicates the maximum number of retransmissions that can be sent for a new connection request.

The TcpMaxDataRetransmissions value indicates the maximum number of retransmissions that can be sent on an existing connection. The default is 5.

The retransmission time-out is adjusted on the fly to match the characteristics of the connection, using Smoothed Round Trip Time (SRTT) calculations… The retransmission time-out for a given segment is doubled after each retransmission of that segment.

According to this document the default value of TcpInitialRtt is 3 and TcpMaxConnectRetransmissions is 2.
So the default connection timeout is calculated like this: 3 + 3*2 + 3*2*2 = 21 seconds,
after you set TcpMaxConnectRetransmissions to 1 it becames: 3 + 3*2 = 9 seconds.


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