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Unformatted text preview: P system. This
allows reconfiguration without having to modify source files and rebuild a kernel.
The configuration program is ndd(l). We can run the program to see what parameters we
can examine or modify in the UDP module: file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/append_e.htm (5 of 16) [12/09/2001 14.48.06] Appendix E: Configurable Options solaris % ndd /dev/udp \?
(read and write)
only) There are five modules we can specify: /dev/ip, /dev/icmp, /dev/arp,
/dev/udp, and /dev/tcp. The question mark argument (which we have to prevent
the shell from interpreting by preceding it with a backslash) tells the program to list all
the parameters for that module. An example that queries the value of a variable is:
solaris % ndd /dev/tcp tcp_mss_def
To change the value of a variable we need superuser privilege and type:
solaris # ndd -set /dev/ip ip_forwarding 0
These variables can be divided into three categories:
1. Configuration variables that a system administrator can change (e.g.,
2. Status variables that can only be displayed (e.g., the ARP cache). Normally this
information is provided in an easier to understand format by the commands
ifconfig, netstat, and arp.
3. Debugging variables intended for those with kernel source code. Enabling some
of these generates kernel debug output at runtime, which can degrade
We now describe the parameters in each module. All parameters are read-write, unless
marked "(Read only)." The read-only parameters are the status variables from case 2
above. We also mark the "(Debug)" variables from case 3. Unless otherwise noted, all the
timing variables are specified in milliseconds, which differs from the other systems that
normally specify times as some number of 500-ms clock ticks....
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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.
- Spring '12