TCP1323Opts is a registry value that controls the use of the TCP Timestamp and Window Scaling options. These options are described in RFC 1323, which is an update to the original TCP/IP specification.

The TCP Timestamp option allows TCP to measure the round-trip time (RTT) between two hosts. This information can be used to improve the performance of TCP connections by adjusting the retransmission timeouts.

The TCP Window Scaling option allows TCP to negotiate a larger receive window size than the default of 64K. This can improve the performance of TCP connections by allowing the sender to send more data at a time.

The TCP1323Opts value can be set to one of three values:

• 0: Disables both the TCP Timestamp and Window Scaling options.
• 1: Enables the TCP Timestamp option.
• 2: Enables both the TCP Timestamp and Window Scaling options.

The default value of TCP1323Opts is 0.

Enabling the TCP Timestamp and Window Scaling options can improve the performance of TCP connections in some cases. However, it is important to note that these options can also increase the latency of TCP connections. Therefore, it is important to experiment with different settings to determine what works best for your network.

To change the TCP1323Opts value, follow these steps:

1. Open the Registry Editor.
2. Navigate to the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
3. Double-click the TCP1323Opts value.
4. Enter the desired value and click OK.
5. Restart your computer for the changes to take effect.

For more information, see TCP Performance Tuning.