Objectives
· Observe the conversion of a URL to an IP
address.
· Observe DNS lookup using the nslookup
command.
Background / Preparation
Domain Name System (DNS) is invoked when
you type a Uniform Resource Locator (URL), such as http://www.cisco.com, into a web browser. The first part of
the URL describes which protocol is being used. Common ones are HTTP
(Hypertext Transfer Protocol), HTTPS (Hypertext Transfer Protocol over
Secure Socket Layer), and FTP (File Transfer Protocol).
DNS uses the second part of the URL,
which in this example is www.cisco.com. DNS translates the domain name
(like www.cisco.com) to an IP address in order to allow the source host
to reach the destination host. Work in pairs to complete this lab.
The following resources are required:
· Windows-based computer with Internet
connectivity
· Access to the Run command
Step 1: Observe DNS conversion
a. Click the Start button, select Run,
type cmd, and then click OK. The command prompt window
appears.
b. At the command prompt, type ping
www.cisco.com. The computer needs to translate www.cisco.com into an
IP address so it knows where to send the Internet Control Message
Protocol (ICMP) packets. Ping is a type of ICMP packet.
c. The first line of the output shows
www.cisco.com converted to an IP address by DNS. You should be able to
see the effect of DNS even if your school has a firewall that prevents
pinging, or if Cisco has prevented people from pinging their web server.
d. Which IP address is shown on the screen?
Jawab:
IP address yang muncul pada layar adalah :
198.133.21925.
e. Is it the same as the one shown in the
figure?
Jawab:
Ya, sama dengan yang ditampilkan pada
gambar di atas.
Why do you think this occurred?
Jawab:
Karena DNS merupakan database yang
menampung semua hostname dari domain yang menunjukkan IP address. Jadi
dari manapun kita mengakses domain tersebut, IP address yang di panggil
tetap saja sama.
f. Work together with another student and
discuss one or two other instances (besides the ping command) in
which the computer would use DNS.
Jawab:
Step 2: Verify DNS operation using the
nslookup command
a. At the command prompt, type the nslookup
command.
b. What is the default DNS server being
used?
Jawab:
Server : Cache
Dns-BTM.telkom.net.id
Address : 203.130.193.74
c. Notice how the command prompt changed.
This is the NSLOOKUP prompt. From this prompt, you can enter
commands related to DNS.
d. At the prompt, type ? to see a
list of all the available commands that you can use in NSLOOKUP mode.
e. Write three commands that you can use
with NSLOOKUP.
Jawab:
- Nslookup host
name
perintah ini
mengatakan “kirimkan saya IP address dari host”
- nslookup
–type=NS host name
kita memberikan
sebuah opsi “-type=NS” dan domain “host name”. Ini menyebabkan nslookup
mengirimkan sebuah query untuk sebuah record bertipe NS ke server DNS
lokal yang default
- nslookup host name server DNS
Pada perintah ini,
kita mengindikasikan bahwa kita menginginkan query dikirimkan ke server
DNS bukan ke server DNS default.
f. At the NSLOOKUP prompt, type www.cisco.com.
g. What is the translated IP address?
Jawab:
IP address yang di terjemahkan adalah
198.133.21925
h. Is it the same as the IP address shown
with the ping command?
Jawab:
Ya sama.
i. At the prompt, type the IP address of the
Cisco web server that you just found. You can use NSLOOKUP to
get the domain name of an IP address if you do not know the URL. Using
the previous procedures, find an IP address associated with www.google.com.
Jawab:
Step 3: Identify mail servers using the
nslookup command
a. At the prompt, type set type=mx to
have NSLOOKUP identify mail servers.
b. At the prompt, type www.cisco.com.
c. What is the primary name server, the
responsible mail address, and the default Time to Live (TTL)?
Jawab:
Primary name servernya adalah ns1.cisco.com
d. At the prompt, type exit to return
to the regular command prompt.
e. At the prompt, type ipconfig /all.
f. Write the IP addresses of all the DNS
servers that your school uses.
Jawab:
g. Type exit to close the command
prompt window.
Step 4: Reflection
a. If your school did
not have a DNS server, what effect would this have on your use of the
Internet?
Jawab:
Mungkin jika tidak ada DNS server, kita
akan sulit aekali menghafalkan setiap IP address untuk masing-masing
domain. Itu di sebabkan tidak ada penerjemah dari nama domain ke IP
address.
b. Some companies do
not dedicate a single server for DNS. Instead, the DNS server provides
other functions as well. Which functions do you think might be included
on a DNS server? Use the ipconfig/all command to help you with
this.
Jawab:
Ketika sebuah
perusahaan tidak mendedikasikan server tunggal untuk DNS, maka harus ada
fungsi
Lab 6.2.3
Exploring FTP
Objective
· Demonstrate how to
use FTP from the command prompt and GUI.
Background / Preparation
File Transfer Protocol (FTP) is part of
the TCP/IP suite. FTP is used to transfer files from one network device
to another network device. Windows includes an FTP application that you
can execute from the command prompt. There are also many free GUI
versions of FTP that you can download. The GUI versions are easier to
use than typing from a command prompt.
When using FTP, one computer is normally
the server and the other computer is the client. When accessing the
server from the client, you need to provide a username and password.
Some FTP servers have a userID named anonymous. You can access
these types of sites by simply typing “anonymous” for the userID,
without a password. Usually, the site administrator has files that can
be copied but does not allow files to be posted with the anonymous
userID.
If your class does
not have an FTP server available, you can download and install a
freeware version, such as Home FTP Server or Cerberus FTP server. The
FTP Server on a computer running the CCNA Discovery Live CD may also be
used. Another computer will act as the FTP client by using FTP from the
command line, a web browser, or download a freeware version of an FTP
client, such as SmartFTP Client or Core FTP LE client. Work in teams of
two to complete this lab.
The following resources are required:
· Windows-based
computer with an FTP client
· FTP server
(Existing FTP server, downloaded freeware, or use Live CD)
Step 1: Examine FTP from the command
prompt
a. Click the Start button,
select Run, type cmd on the command line, and then click OK.
b. At the prompt,
type ftp to start the FTP application. The prompt changes.
c. From the ftp prompt,
type ? to see a list of the commands that can be used in this
mode.
d. List three FTP
commands.
Jawab:
- Help get
- Help send
- Help recv
e. At the prompt, type help put to
see a short description of the put command.
f. What is the purpose of the put command?
Jawab
Fungsi put adalah
meletakkan satu file ke server
g. Use the help command again to get
the purpose of the get, send, and recv commands.
get
Jawab:
Perintah get digunakan untuk mengambil
file dari server (download)
send
Jawab:
Perintah send digunakan untuk menerima
file dari server (upload)
recv
Jawab:
Perintah recv digunakan untuk menerima
file dari server,
NOTE: The original FTP
commands were PUT to send a file to an FTP server and GET to download a
file from the FTP server. You also had to select ASCII or binary file
mode. If you download a binary file in ASCII mode it could end up being
corrupted. Some of the newer graphical programs now use send and receive
in their place.
h. Partner with another student. Using
procedures demonstrated in previous labs, write down the names and IP
addresses of each partner computer. It is very important to get these
names correct. Some FTP applications allow you to use either the IP
address or the computer name.
Computer 1:
192.168.10.1
Computer 2:
192.168.10.2
Step 2: Use a GUI
FTP client or web browser
a. If you are using a web browser as the FTP
client, open the web browser and type ftp://ip_address_of_FTP_server.
If the FTP server is configured to use an anonymous userID, connect
directly to the FTP server. Using the FTP client, download an available
file from the server.
b. If you are using a
GUI FTP client, open the application. For most FTP clients, you must
configure a new connection by giving it a name, the IP address of the
FTP server, and a username and password. You may have to type anonymous
if the FTP server allows this type of connection. Some applications
have a checkbox that allows an anonymous login. When you have
configured the connection, connect to the FTP server and download a
file.
c. What is the name
of the file you downloaded from the FTP server?
Jawab:
Nama
file yang di download adalah “Modul CCNA”
d. List one example of when FTP might be
beneficial to a computer technician.
Jawab:
Salah satu contoh kegunaan FTP untuk
teknisi computer adalah, ketika kita membutuhkan sebuah data atau ingin
memberikan data kepada computer lain kita tidak perlu susah-susah untuk
mengkopi data dari computer satu dan menyalinnya ke computer lain, tapi
dengan file transfer protocol kita bisa sharing data dengan mudah dengan
menggil IP dari computer source ke computer destination.
Step 3: (Optional)
Use both an FTP server and client
a. If you control both the FTP server and
client, practice sending files to and getting files from the client and
the server.
b.
Show your transferred files to another group of students.
c. Close the FTP server and client
applications.
Lab 6.2.4 Configuring an
Email Client
Objectives
· Set up an email client.
· Send and receive mail from a mail server.
· Add an email account or change an
existing one.
Background /
Preparation
An email application gives the user the
ability to send and receive messages from another user located on
thesame local network or on the Internet. The messages are sent by the
sending client and stored on an emailserver. Another email client with a
mailbox on the server can then access the server at any timeto receive
stored messages that are destined for that client.
The following resources are required:
· Windows-based computer with Internet
connectivity
· Microsoft Outlook or other email client
software
Step 1: Open
Microsoft Outlook
a. From the Start menu,
select All Programs. Locate the Microsoft Office software.
b. Select Microsoft
Office Outlook as the email program. If your computer does not have the
Microsoft Office software, there are many free email software packages
available on the Internet. Search the Internet to find a free email
client that can be installed on your computer. The following
instructions may vary depending on your email client.
Step 2: Set up an email account
a. When you first start Microsoft Outlook, a
screen appears with Email Upgrade Options. You can choose to
import email messages or address books from another account. Because
this is your first email account, select the Do Not Upgrade button.
b. The next screen is the Email Accounts screen
where you are asked if you want to configure an email account. Click Yes.
c. If Outlook has already been installed and
setup for e-mail previously, you can start the Outlook application and
click Tools, E-Mail Accounts and then select View or
change existing e-mail account to see how the existing account is
set up.
Step 3: Enter POP3
e-mail account information
a. The next screen requires the user of the
new account to fill in information. Enter your name and email address.
Your can get your email address from your Internet provider.
NOTE: If you do
not have a real ISP email account, this step can be treated as a
simulation. Just enter the information requested to become familiar with
the process of creating an email account.
b. Enter your server information. Contact
your Internet provider to locate the server information for the incoming
and outgoing mail servers. Usually Internet providers put this
information on their website in heir help section.
c. What is your
incoming (POP3) mail server?
Jawab:
A server that supports POP clients
receives and stores messages addressed to its users. When the client
connects to the email server, the messages are downloaded to the client.
By default, messages are not kept on the server after they have been
accessed by the client. Clients contact POP3 servers on port 110.
d. What is your
outgoing (SMTP) mail server?
Jawab:
SMTP is used by an email client to send
messages to its local email server. The local server then decides if the
message is destined for a local mailbox or if the message is addressed
to a mailbox on another server.
If the server has to send the message to a
different server, SMTP is used between the two servers as well. SMTP
requests are sent to port 25.
e. Enter your username
and password. Do not check the box to remember your password. This
option is used when only one person uses the computer. If anyone else
were to use the computer, they could easily gain access to all of the
information in your email.
f. Click the Test
Account Settings button. If everything is correct, the screen
displays that the test was successful. If not, correct your information
and try again.
NOTE: If this is a
simulation, the test will not be successful and you can go to Steps 4
and 5.
g. Test your new
account by sending an email to a friend in class.
Step 4: (Optional) Add another account or
change an account
a. Open Microsoft Outlook. From the Tools
menu, select Email Accounts.
b. In this screen, you
can add another email account or you can change information in an
existing account.
Step
5: Reflection
a. What are the
advantages or disadvantages to using email over regular postal mail?
Jawab:
- Keuntungan menggunakan regular postal
mail adalah dari segi keamanan lebih tinggi karena lebih jelas pemilik
account yang mengirim dan yang akan menerima, dan lebih di akui ke
absahan surat yang kita kirimkan karena ternasuk jenis surat elektronik.
- Kelemahannya adalah surat yang dikirim
menggunakan regular postal mail terkadang lama di jawab oleh penerima,
karena terjadi tidak real time atau terjadi pada saat ke dua penerima
atau pengirim belum tentu dalam keadaan online. Jadi bisa saja penerima
tidak membuka accountnya dalam kurun waktu tertentu.
b. What are the
advantages or disadvantages to using email over an instant messaging
program?
Jawab:
- Keuntungan menggunakan instant messaging
program adalah terjadi pada real time jadi penerima pesan di pastikan
menerima pesan secara langsung, karena kedua-duanya dalam keadaan online
- Kelemahannya instant messaging program
tidak memiliki kekuatan hukum karena tidak ada arsip ketika penerima
atau pengirim offline. Dan keamanannya juga tidak terlalu dijamin karena
bisa saja pengguna menggunakan account samaran.
c. With a partner,
discuss five (5) recommendations for email etiquette that should be
considered when emailing friends and business colleagues.
- Email harus
disertai nama pengirim dan identitas lainnya
- Email harus
disertai nama tujuan/ penerima
- Email harus diberi
judul/ subject agar penerima dapat mengerti tujuan surat sebelum di
baca.
- Email hendaknya menggunakan bahasa yang
baik
- Lima menit antara menerima dan membalas
email
- Tulis isi email dengan jelas.
- Tuliskan email
secara pendek dengan kata-kata yang baik.
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