Service manual

Tuning System Settings
106 Sun ONE Directory Server Installation and Tuning Guide • June 2003
Retransmission Timeout
Some systems allow you to configure the initial time interval between
retransmission of packets. This setting affects the wait before retransmission of an
unacknowledged packet. When set too high, clients may be kept waiting on lost
packets. For intranet deployments on fast and reliable networks, setting this
parameter to a value of 500 milliseconds may improve performance.
OnSolarissystems,thistimeintervalisconfiguredthroughthe
tcp_rexmit_interval_initial parameter, as described in the output of
/usr/sbin/directoryserver idsktune (packaged version) or idsktune (no
packages).
Windows can implement the Van Jacobson TCP fast retransmit and recovery
algorithm to retransmit quickly missing segments upon the receipt of an ACK
without waiting for the retransmission timer to expire. To implement the Van
Jacobson algorithm, edit the registry key:
HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Tcpip/Parameters
Add TcpMaxDupAcks having type REG_DWORD. Set the value to the number of ACKs.
The range is 1-3, and the default is 2.
Sequence Numbers
Some systems allow you to configure how the system handles initial sequence
numbergeneration. For extranet andInternetdeployments,setthisparameter such
that initial sequence number generation is based on RFC 1948 to prevent sequence
number attacks.
OnSolarissystems,thisbehaviorisconfiguredthroughthe
tcp_strong_iss
parameter, as described in the output of /usr/sbin/directoryserver idsktune
(packaged version) or idsktune (no packages).