Linux and Tcp/Ip Networking Report

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  • Topic: Transmission Control Protocol, Internet Protocol Suite, Internet Protocol
  • Pages : 5 (1015 words )
  • Download(s) : 129
  • Published : September 25, 2012
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Exercise 2
LAB REPORT
Q:What is the default directory when you open a new command window? What is your working directory? A:
/home/guest/
/home/guest/fangyuliu

Exercise 3
LAB REPORT
Q:Is the Internet service daemon, xinetd, started in your system? Is inetd started in your system? Why?
A:xinetd(extended Internet daemon) is started in my system rather than inetd (internet service daemon). Both of them are super-server daemon started only under request. Because xinetd is more secure than inetd, more Unix- services now replace inetd with xinetd.

Exercise 4
Q:Compare the file ser_more and ser_cp. Are these two files identical? A:Yes, they are identical.

Q:Display the file sizes using ls –l ser*. Save the output. What are the sizes of files A: ser_more, ser_cp, and ser_cat?
ser_cat 39870 bytes
ser_cp 19935 bytes
ser_more 19935 byte

LAB REPORT
Q:Submit the ls output you saved.
A:
[guest@guchi guest]$ ls -l ser*
-rw-rw-r-- 1 guest guest 39870 Sep 17 05:38 ser_cat -rw-r--r-- 1 guest guest 19935 Sep 17 05:34 ser_cp -rw-rw-r-- 1 guest guest 19935 Sep 17 05:20 ser_more

Exercise 5
arp arping ifconfig tcpdump
ping netstat route ethereal
-----------------------------------------
LAB REPORT
Q:Explain the above commands briefly.
A:
arp(address resolution protocol): Displays and modifies address resolution arping: Capture ARP packets on the remote machine.
ifconfig: Configures or displays network interface parameters for a network using TCP/IP. tcpdump: Capture and display packets on the LAN segment.
ping: Sends an echo request to a network host.
netstat: Work in conjunction with the ifconfig command to provide a status condition of the TCP/IP network interface. route: Manually manipulate the routing tables.
ethereal: Capture network packets and provide a user friendly graphical interface and support additional application layer protocols.

Exercise 6
LAB REPORT
Q:Draw the format of the packet you saved, including the link, IP, and TCP headers, and identify the value of each field in these headers. A:
Link Header
00:16:76:a9:81:ee(Destination Address)| 00:09:5b:0a:ea:03(Source Address)| 0x0800(Frame Type: IP)| N/A(Data)| N/A(CRC)|

IP header
Version: 4| Header length: 20 bytes| Differentiated Services Field: 0x10| Total Length: 52| Identification: 0xe535| Flags: 0x04| Fragment offset: 0| Time to live: 64| Protocol: TCP (0x06)| Header checksum: 0xcece (correct)| Source: 128.238.66.104|

Destination: 128.238.66.107|
Option: N/A|
Data: N/A|

TCP Header
Source port: 33510 (33510)| Destination port: telnet (23)| Sequence number: 3192985136|
Acknowledgement number: 1082427947|
Header length: (32 bytes)| Reserved(N/A)| Flags: 0x0011 (FIN, ACK)| Window size: 5840| TCP Checksum: 0x8151 (correct)| Urgent Pointer: N/A|
Optional(12 bytes): NOPNOP|
Data: N/A|

LAB REPORT
Q:What is the value of protocol field in the IP header of the packet you saved? What is the use of the protocol field?
A:
The value of protocol field in the IP header is 0x06 which is TCP. The use of this is to show the upper layer protocol.

Exercise 7
Q:What is the value of the frame type field in an Ethernet frame carrying an ARP request and in an Ethernet frame carrying an ARP reply, respectively? A: The frame type field in an Ethernet frame carrying an ARP request is 0x0806. The frame type field in an Ethernet frame carrying an ARP reply is 0x0806. Q:What is the value of the frame type field in an Ethernet frame carrying an IP datagram captured in the previous exercise?

A:Frame type field in an Ethernet frame carrying an IP is 0x0800.

Q:What is the use of the frame type field?
A:Indicate which protocol is encapsulated in the payload of an Ethernet Frame.

Exercise 8
LAB REPORT
Q:Explain briefly the purposes of the following tcpdump expressions. A:
tcpdump udp port 520: Capture traffic of UDP 520...
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