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Unformatted text preview: for information on a person, institution, domain, or
The other Internet resource discovery services that we briefly described, Archie, WAIS,
Gopher, Veronica, and WWW, help us locate files and documents across the Internet. Other
resource discovery tools are currently being developed.
This chapter finished with a brief look at the X Window System, another heavy user of
TCP/IP. We saw that the X server manages multiple windows on a display, and handles the
communication between a client and its window. Each client has its own TCP connection to
the server and a single server manages all the clients for a given display. With the Xscope
program we saw how it's possible to place another program between a client and server to
output information about the messages exchanged between the two.
30.1 Use Whois to find the owner of the class A network ID 88.
30.2 Use Whois to find the DNS servers for the whitehouse.gov domain. Does the reply
match the answer given by the DNS?
30.3 In Figure 30.3, do you think the xscope process must be run on the same host as the X
server? file:///D|/Documents%20and%20Settings/bigini/Docu...ti/homenet2run/tcpip/tcp-ip-illustrated/other.htm (11 of 11) [12/09/2001 14.47.58] Appendix A: The tcpdump Program The tcpdump Program
The tcpdump program was written by Van Jacobson, Craig Leres, and Steven
McCanne, all of Lawrence Berkeley Laboratory, University of California, Berkeley.
Version 2.2.1 (June 1992) is used in this text.
tcpdump operates by putting the network interface card into promiscuous mode so that
every packet going across the wire is captured. Normally interface cards for media such
as Ethernet only capture link level frames addressed to the particular interface or to the
broadcast address (Section 2.2).
The underlying operating system must allow an interface to be put into promiscuous
mode and let a user process capture the frames, tcpdump support is provided or can be
added to the following Unix systems: 4.4BSD, BSD/386, SunOS, Ultrix, and HP-UX.
Consult the README file that accompanies the tcpdump...
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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