TCP IP Illustrated

Directedbroadcast the value of this constant

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Unformatted text preview: nabled. SUBNETSARELOCAL The value of the kernel variable ip_subnetsarelocal is initialized from this constant. If 1 (default), a destination IP address with the same network ID as the sending file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/append_e.htm (3 of 16) [12/09/2001 14.48.06] Appendix E: Configurable Options 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 variable tcp_default_mss. IPSENDREDIRECTS The value of this constant initializes the kernel variable ip_sendredirects. If 1 (default), the host will send ICMP redirects when forwarding IP datagrams. If 0, ICMP redirects are not sent. DIRECTED_BROADCAST The value of this constant initializes the kernel variable ip_dirbroadcast. If 1 (default), received datagrams whose destination .address is the directed broadcast address of an attached interface are forwarded as a link-layer broadcast. If 0, these datagrams are silently discarded. The file /usr/kvm/sys/netinet/in_proto.c defines the following variables that can be changed. Once these variables are changed, a new kernel must be made and rebooted. tcp_default_mss The default TCP MSS for nonlocal destinations. Default value is 512. tcp_sendspace The default size of the TCP send buffer. Default value is 4096. tcp_recvspace The default size of the TCP receive buffer. This affects the window size that is offered. Default value is 4096. tcp_keeplen A keepalive probe to a 4.2BSD host must contain a single byte of data to get a response. Set the variable to 1 for compatibility with these older implementations. Default value is 1. tcp_ttl The default value for the TTL field for TCP segments. Default value is 60. tcp_nodelack If nonzero, ACKs are not delayed. Default value is 0. tcp_keepidle Number...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.

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