Chapter 7 (Using Network Clients) Flashcards
A program making requests
A Client
— is a terminal emulation program
Telnet
— is not designed to transfer any information between computers except your keystrokes as you type, and the characters that are displayed on the screen.
Telnet
—- lists the users that are logged in on all hosts attached to the local network that have the r-utilities networking features activated.
rwho
—- lists all hosts attached to the local network (that are using r-utilities) with the uptime for each
ruptime
— logs in to a remote host; very similar to telnet, but uses the r-utilities authentication methods described in this section.
rlogin
you can enter the — command with the -l option to specify the account name on oslo that you want to use.
rlogin
you can use the — command to execute a program on a remote host without logging in
rsh
to copy files between a host (r-utilities)
rcp
A — procedure is a procedure that can repeat itself indefinitely.
Recursive
The SSH package includes utilities such as —, which acts like rcp, letting you copy files between any two computers on your network with full encryption.
scp
This process of copying an entire website or FTP site is called —.
Mirroring
(wget command line option)
Download all supporting files to permit local display if a web page referred to on the wget command line.
-p
(wget command line option)
Converts links in a download web page so that they refer to the download supporting files (such as images)
-k
(wget command line option)
Retry the download the stated number of times if the download of the web page is interrupted for any reason.
-t 40
(wget command line option)
View web page header information as the page and other files are downloaded.
-s
(wget command line option)
Save downloaded web page header information to a file.
-s
(wget command line option)
Use recursive downloads
-r
(wget command line option)
Set the number of levels for recursive downloads; used with the -r option
-I 3
(FTP commands)
Turn on binary mode
Bin
(FTP commands)
Exit the FTP program
Bye
(FTP commands)
Copy a file from one location to another on the FTP server; normally requires regular user access to the FTP server ( not just anonymous access)
cp
(FTP commands)
Download a file
Get (file name)
(FTP commands)
List files contained in the current directory on the FTP server.
ls
(FTP commands)
Download multiple files using regular expression (such as .tgz)
Mget (expression)
(FTP commands)
Create new directory on the FTP server; normally requires regular user access to the FTP server
Mkdir
(FTP commands)
Upload multiple files using a regular expression (such as .html)
Mput expression
(FTP commands)
Turn on or off prompting for download or upload of individual files when using mget or mput commands.
Prompt
You can enter — command to view the active networking interfaces.
ifconfig
The — —- assigned to each interface is labeled inet addr on the second line of the corresponding section.
IP address
The — utility sends a diagnostic data packet to the computer you specify
ping
The ping command sends a series of – byte packets to the host with the IP address
64 byte
What are the two major benefits of using traceroute?
Finding where a packet stops
Finding where a packet slows down
Three well known methods of accessing Linux systems remotely are —, the — and the — suite of utilities. The first two are considered unprotected and highly vulnerable and should not be used except for convenience on networks that are completely trusted.
Telnet, r-utilities, ssh
The — — let you access a remote system without entering a password.
r-utilities
Starts the — graphical utility used to manage downloads of web pages.
kget
A more advanced version of the ftp utility
ncftp
Synchronizes a set of files that is stored on two or more systems and needs to be kept consistent as changes are made to the files.
rsync
(wget command line option)
Mirror a web site using a recursive download of web pages
-m
Telnet is able to do the following
- Log into a remote computer
- You can view any files that your user account permits you to use
- You can also execute any command, including changing or deleting files.
To be able to telnet, you need to know the following.
- The remote host to which you want to connect. (Domain name or IP address)
- Port number (default is 23)
- The type of terminal that you want the software to emulate (standard choice is VT100)
- Username and password
— are most effective when you can set up a configuration file on multiple computers where you have a user account.
r-utilities
(note) You can enter the rlogin command with the -l option to specify the account name that you want to use.
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You can create a hidden file in your home directory called — containing a list of hosts and user names that you want to permit access your account without a password.
.rhosts
The — — is configured in the file /etc/ssh/sshd_config.
sshd daemon
To check the status of the sshd server program, use the following command on the sever while logged in as root.
service sshd status
If the server is ready to accept client connections, you should be able to use the following command on the client to connect to sshd on the server.
$ ssh -l username server
(note) the ssh_host_rsa_key.pub contains a public key
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– and — are two types of encryption supported by ssh
RSA and DSA
The default key length is?
1024 bits
to alter the length of a ssh key, use this command
-b
(Example) ssh-keygen -t rsa -b 2048
You can limit the number of recursive levels of recursive levels using the – option to turn on recursive downloads and the – option to set the number of levels of recursion to use
- r
- l
