Data type


Default value


0x0–0xFFFFFFFF ( retransmission attempts )



Determines how many times TCP retransmits an unacknowledged data segment on an existing connection. TCP retransmits data segments until they are acknowledged or until this value expires.

TCP/IP adjusts the frequency of retransmissions over time. TCP establishes an initial retransmission interval by measuring the round trip time on the connection. The interval doubles with each successive retransmission on a connection, and it is reset to the initial value when responses resume.

This entry is also used in the Windows algorithm for defining non-operational ( dead ) gateways.

A given connection defines a gateway as dead (and switches to the next gateway in the list in stored in the value of the DefaultGateway or DhcpDefaultGateway entries) when a packet sent to the gateway must be retransmitted more than half of the number of times specified in the value of this entry. The system defines a gateway as dead when more than 25 percent of its connections have switched to the next default gateway in the list.

Note Image Note

This entry determines how many times TCP retransmits data segments. The maximum number of retransmissions of requests for new connections is determined by the value of the TcpMaxConnectRetransmissions entry.

Windows 2000 does not add this entry to the registry. You can add it by editing the registry or by using a program that edits the registry.

Related Entries

Page Image