Communicate securely

Development of a technology for the good is always accompanied with the development technologist for the crime. It is commonplace existence. Reject a certain development is not possible. Expects the technology solely for the good of course also clearly impossible. Computers connected to the Internet and data later stolen. Computers can be used to modify the images and pictures fine then modified for the purpose of defamation. Computers easier to use and the virus was developed by various circles. For those of you who every day works to send data over a network, your data at risk to be tapped. You open the webmail and then fill in the password. You log into the server to perform simple administration and various other examples. The best way to compromise is to prevent. Surely not prevent the development of a technology or prevent the use. However, try to use something that is currently shown to be safe. If you always use
telnet, replace immediately. If you are still using ftp, use another protocol. We will show you how some of the protocol is very vulnerable to be tapped. And the tapping process can be done by anyone, because the program has available to it. Not cracker who can tap the information you send via telnet. Provided that can operate the tool
to tap, anyone can do the wiretaps. This is not the strings attached.

Below we will see how extracting such information is very easy to do. To test this, run telnet server on your computer. Telnet is a protocol that is very vulnerable, because all information is transmitted in cleartext. To conduct wiretaps, we will use the program Ethereal, which can be downloaded at http://www.ethereal.com.However, first try to check the packages your distro, since Ethereal including a very common program bundled with the distro.
Ethereal GUI based and very easy to use. Feature was very complete. Run the telnet server. Telnet server is usually run by inetd or xinetd. As root, run too ethereal, and immediately access the menu Capture | Start. A dialog will
displayed and make sure the field interface, you select any. Click OK to immediately start tapping. A dialog will be displayed statistics. Open your terminal emulation and telnet connection to the server do. You'll find the typical appearance of the login prompt, and do authentication. After that, give some command like:
-Ls
-Whoami
-Logout

Observe statistics screen tapping. Certainly at the TCP will show a number greater than zero, which shows the captured packets. Close your terminal emulation and telnet server may be disabled. Click the Stop button in the dialog also statistically Ethereal because tapping has been completed. On the main screen your Ethereal, will perform a variety of texts that show the results of tapping. As we promised that wiretapping can be done easily, forget about the texts and angkaangka it. Kananlah Click on any of the entries, and choose Follow TCP Stream. A new window will open and like to see history, you'll see the whole of your telnet session before, including his password. Obviously. Ready stolen. Ready misused. This shows that using something that is not safe is very risky. Never again using telnet. If you are forced to do a remote shell connection, use ssh. Do the same intercepts on ssh and you will only see the characters do not mean
when you do the Follow TCP Stream. Below, we will discuss
some replacement tools for the tool-toolyang aman.Tool no-tool that we shall certainly does not promise 100% security, but, for now, safer to use.

Telnet and ssh
In the previous section, we have learned to tap into a telnet session. With Ethereal, tapping can be done very easily. Telnet itself has been used since awalawal
unix time. Flexibility given the admittedly deserved thumbs up. However, you see for yourself how easy it is to do the wiretapping of a telnet session. If you are still using telnet, immediately stop and Switch to ssh. If the administrator
Your network still apply telnet server, immediately ask to enable the ssh daemon.Same functionality and ssh obviously much safer. Here are a few things around the use of ssh:
*) First. Do not be surprised when first asked about fingerprint ssh RSA and others.Host key verification as this is only done once and further, will actually resemble a telnet session.
*) There are several front end for ssh.Apabila you use KDE, try KSSH. Not very good indeed, but at least, you do not need to remember the various options ssh ssh because some options can be selected in KSSH.
*) There are two SSH protocols. If
have free time, read the manual
ssh, where you will get
lengthy explanations about the
both these protocols.
*) SSH haldalam can display a variety of detailed shapes. Just give me the option-v, and you will see verbose display. The more-v options are given, the more detailed the information you get.
*) Compression supported to minimize the size of data transferred.Dengandemikian, if you do a remote shell connection to the Internet and quite slow, is expected to enable compression, data transfer can be done more quickly.

Secure copy: scp
You want to copy a file from another computer on the network Anda.Kebetulan, the computer does not enable file sharing whatsoever. FTP server also not enabled.The ssh daemon is activated. In such scenarios, you can use scp to copy a file from another computer as long as you have the right or the account and know the location of the file. If you have an account, then the location of the file of course can be seen when you open an ssh session to that computer. By using scp, you can perform the copying either single files or directories recursively. Thus, you need not bother to enable file sharing or FTP session opened. In addition, with scp, you can copy files from a computer or copy the files to a computer. Most of the scp option similar to the cp program options. The difference is, with scp, the copying can be done safely through the network. As a bonus, scp also displays a progress bar that attracts so many more informative because pengopian through the Internet, for example, can take quite a long time. Here are some examples of the use scp:
$ Scp a nop@192.168.1.2: ~ / a_copy
*) This command will copy the files to the home directory on the computer 192.168.1.2 nop. A file will be copied into the file a_copy.
$ Scp a * nop@192.168.1.2: / tmp
*) This command will copy the files whose name begins with a character to the / tmp directory on your computer
192.168.1.2.
$ Scp-r song nop@192.168.1.2: / tmp
*) This command will recursively song mengopikan directory to the directory / tmp on computer 192.168.1.2.
Nop@192.168.1.2 $ scp: / boot/vmlinuz-
02.04.21-192-default ~ /
*) This command will copy the file / boot/vmlinuz- 2.4.21-192-default of 192.168.1.2 to the computer user's home directory is active.
Here are some things about
use scp:
*) Unlike his cousin, rcp, who both do the copying copying files, scp will ask for a password if necessary.
*) Scp uses ssh for data transfer and uses the same ability to ensure data security.
*) At the moment we are on computer A, you can copy a file from computer B to computer C. So, pengopian between two remote hosts are possible. Remarkable.What you need is the login information and files.
*) Scp were quite understand the bandwidth limitations. Therefore, you can also limit the bandwidth used by the SCP in units Kbit / s.
*) Just like ssh, scp also supports compression. In copying the files, compression can increase transfer speed, although you will sacrifice the time to do the compression / decompression.

FTP and SFTP
In the previous section, we have seen the use of ssh and scp, each to a remote shell and copying the files
inter-host. With both these tools, you can perform administrative actions at once to transfer files. For those of you who often work in the world and used to send send files with FTP, you can still use a similar tool, but in a way that
safer. Use SFTP! Command similar orders!
Here are a few things around the use sftp:
*) Just like scp, sftp ssh can also take advantage of capabilities such as encryption and compression.
*) Sftp allows the batching process, so that commands can be given in a batch file, instead of manually typing in different commands. This feature is very useful.

For the needs of remote shell connections and file transfers, starting today, for you are still using telnet and ftp, immediately forget about the tool. Begin to use ssh, scp, or sftp. Server settings for all of these tools were very simple. You only need the ssh daemon. Data security is a very important issue. Never underestimate the occasional
slightest thing in data security. Because, many parties out there who are ready to abuse the data gets.