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Unformatted text preview: for datagrams sent through the loop-back
interface. If 0, this checksum is not calculated.
If 1 (default), received datagrams containing a source route option are forwarded. If 0,
these datagrams are discarded.
If 1 (default), a destination IP address with the same network ID as the sending host but a
different subnet ID is considered local. If 0, only destination IP addresses on an attached
subnet are considered local. This is summarized in Figure E.1. When sending to local
destinations, TCP chooses the MSS based on the MTU of the outgoing interface. When
sending to nonlocal destinations, TCP uses the default (536) as the MSS.
Number of 500-ms clock ticks before sending a keepalive probe. Default value is 14400
Number of 500-ms clock ticks between successive keepalive probes, when no response is
received. Default value is 150 (75 seconds).
The default size of the TCP receive buffer. This affects the window size that is offered. file:///D|/Documents%20and%20Settings/bigini/Doc...omenet2run/tcpip/tcp-ip-illustrated/append_e.htm (14 of 16) [12/09/2001 14.48.06] Appendix E: Configurable Options Default value is 16384.
The default size of the TCP send buffer. Default value is 16384.
The default value for the TTL field for TCP segments. Default value is 60.
The default size of the UDP receive buffer. The default is 41600, allowing for 40 1024byte datagrams.
The default size of the UDP send buffer. Defines the maximum UDP datagram that can
be sent. Default is 9216.
The default value for the TTL field in UDP datagrams. Default value is 30. E.6 4.4BSD
4.4BSD is the first of the Berkeley releases to provide dynamic configuration for
numerous kernel parameters. The sysctl(8) command is used. The names for the
parameters were chosen to look like MIB names from SNMP. To examine a parameter
vangogh % sysctl net.inet.ip.forwarding
net.inet.ip.forwarding = 1
To change a parameter we need superuser p...
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