“21天好习惯”第一期-14

自己完成的一份计算机网络实验
实验三：DNS
实验步骤

1. Run nslookup to obtain the IP address of a Web server in Asia. What is the IP
   address of that server?

IP address:14.215.177.39 and 14.215.177.38
2. Run nslookup to determine the authoritative DNS servers for a university in
Europe.

3. Run nslookup so that one of the DNS servers obtained in Question 2 is queried for
   the mail servers for Yahoo! mail. What is its IP address?

My computer Unknow yahoo.com
4. Locate the DNS query and response messages. Are then sent over UDP or TCP?

UDP
5. What is the destination port for the DNS query message? What is the source port
of DNS response message?

Source port:52964 Destination port:53
6. To what IP address is the DNS query message sent? Use ipconfig to determine the
IP address of your local DNS server. Are these two IP addresses the same?

Two IP addresses was different
7. Examine the DNS query message. What “Type” of DNS query is it? Does the
query message contain any “answers”?

8. Examine the DNS response message. How many “answers” are provided? What
   do each of these answers contain?
   Provide 4 “answers”, the content is described above

9. Consider the subsequent TCP SYN packet sent by your host. Does the destination
   IP address of the SYN packet correspond to any of the IP addresses provided in
   the DNS response message?
   Yes

10. This web page contains images. Before retrieving each image, does your host
    issue new DNS queries?
    No , only some of the new DNS queries were issusd.

11. What is the destination port for the DNS query message? What is the source port
    of DNS response message?

Src port:65060 Dst port:53
12. To what IP address is the DNS query message sent? Is this the IP address of your
default local DNS server?
Src: 2001:250:6c04:101:82fa:5bff:fe6f:c2e8, Dst: 2001:250:6c04:1::62
Yes is default
13. Examine the DNS query message. What “Type” of DNS query is it? Does the
query message contain any “answers”?

Type A, not any contain
14. Examine the DNS response message. How many “answers” are provided? What
do each of these answers contain?

15. Provide a screenshot.

16. To what IP address is the DNS query message sent? Is this the IP address of your
    default local DNS server?

Src: 2001:250:6c04:1::62, Dst: 2001:250:6c04:101:82fa:5bff:fe6f:c2e8
Yes is default
17. Examine the DNS query message. What “Type” of DNS query is it? Does the
query message contain any “answers”?

Type “NS”, the query message does not contain any answers
18. Examine the DNS response message. What MIT nameservers does the response
message provide? Does this response message also provide the IP addresses of the
MIT namesers?

The response message does not provide the IP address of the MIT domain name server
19. Provide a screenshot.

20. To what IP address is the DNS query message sent? Is this the IP address of your
    default local DNS server? If not, what does the IP address correspond to?

Sent IP address:202.101.224.69 Not default, It’s 18.0.72.3
21. Examine the DNS query message. What “Type” of DNS query is it? Does the
query message contain any “answers”?

Type A, the query message does not contain any answers
22. Examine the DNS response message. How many “answers” are provided? What
does each of these answers contain?

23. Provide a screenshot.