Anonymous Ftp Servers example essay topic

Internet and its services. Richard Z uber DL Efficient and Effective Self-Expression BC 302 Bill BagatelasResearch Paper 11/24/2001 Working with Internet does not mean just browsing and sending and receiving e-mails. The Basic Structure of the Internet was developed through last 30 years of existence of the Internet. The Internet is a heterogeneous worldwide network consisting of a large number of host computers and local area networks.

The Internet uses the TCP / IP suite of protocols. This allows the integration of a large number of different computers into one single network with highly efficient communication between them. This way, the user can access information on all kinds of host computers from a desktop PC, Macintosh, or whatever he / she has available. TCP / IP, the communication standard underlying the Internet, originates from work done at the US-Department of Defense in the late 1960's.

The first version of the Internet was built in 1969 and consisted of just four computers. In 1982 a set of specifications and protocols have been implemented, which became known as TCP / IP in reference to their two major elements, the 'Transmission Control Protocol' and the 'Internet Protocol'. The development and implementation of TCP / IP stimulated a massive growth process for the Internet. 'By late 1987 it was estimated that the growth had reached 15% per month and remained high for the following two years. By 1990, the connected Internet included over 3,000 active networks, over 3,000 active networks, and over 200,000 computers. By January 1992 the number of hosts on the Internet was 727,000, doubling about every 7 months.

Various groups of users are connected to the Internet: universities and other educational institutions, government agencies, the military, and at an increasing number private businesses. The most fundamental function of the Internet is to pass electronic information from one computer to another. A 32 bit Internet Address or IP-Number identifies every computer on the network. This number is commonly represented as four numbers joined by periods. The Internet uses these numbers to guide information through the network. This is called routing.

For human users, however, such numbers are usually difficult to keep in mind. Therefore, computers are also identified by Domain Names, which are to some extent similar to mailing addresses. Special programs, called name servers, translate domain names into IP-Addresses. Internet services can be divided into two groups, communication services, and information services. In the first group, the Internet mediates in the communication between two or more individuals. In the second group, the user turns to the Internet-service in search for some particular information.

Communication services can roughly be compared to a telephone call, information services to a dictionary. The most important communication services on the Internet are electronic mail, Netnews and some derived services. Major information services are terminal emulation and file transfer, Gopher, WAIS, and World Wide Web. Electronic mail is the most popular and widely used network service. It can be viewed as the electronic equivalent to a regular mail letter. When one user wants to send a message to another Internet user, he types the message into a special computer program, adds the e-mail address of the recipient, and sends the message off through the network.

Typically, the message reaches its destination almost immediately, even when it is on another continent. Practically all gateways between the Internet and other computer networks can handle e-mail messages. Therefore, many more people can be reached by e-mail than are connected to the Internet via TCP / IP. The major advantage of e-mail over regular mail is that an e- mail message comes in electronic form. Therefore, it can easily be handled and interpreted by a computer program. This feature is use by electronic discussion lists.

They operate a database of subscribers and each incoming e-mail message is automatically distributed to each subscriber. Listserv, the most popular program for managing discussion lists also handles subscription via mail messages, archives incoming messages, and allows users to retrieve these and other archived files. Thousands of discussion lists focusing on all kinds of topics exist on the Internet. Topics range from various hobbies, political discussions to operational aspects of different computer systems and research questions. For the user, discussion lists are an easy way to identify and contact a large number of people with similar interests.

A discussion list can also be considered as a worldwide forum for expressing views and discussing opinions. While messages are automatically sent to all subscribed users in the case of a discussion list and one has to be subscribed in order to receive the messages, messages in Netnews are distributed between a net of servers. Messages are organized in a hierarchy of newsgroups. Incoming messages are stored for a particular period in a publicly accessible area. Each user can connect to this area, browse through the stored messages, and respond to any one of them.

This way Netnews allows for a better overview of ongoing discussions but requires the user to actively connect to the respective area. One of the reasons for the creation of a computer network like the Internet was to give users access to remote computers and to allow them to transfer files to and from this machine. These are typical demands for Telnet and FTP for file transfer protocol. In both services, the user specifies a specific remote host through its IP-number or domain-name that he wants to access. When the user has an account on this remote host, he can work there just like on a local machine. With telnet available, increasingly Internet-sites allowed outside users to access some of their information services.

Typical examples are electronic library card catalogs, campus information systems, and other database applications. Today, the electronic card catalogs of practically all-major libraries and many university libraries in Europe are publicly accessible through the Internet. Many sites run large specialized information systems for the network community. A similar type of anonymous access is available through FTP. Many Internet sites allow users to log in as anonymous through FTP.

The way the sites can make files publicly available. This system has led to a huge supply of freeware- and shareware-software that is distributed through this channel. Practically all network software is available in this way. In addition, information files specifications of network standards; research papers, multimedia files, and even the complete texts of classical books can be accessed through anonymous FTP.

When using an FTP client program to download files, assure yourself, that it is giving a bogus password, like, not your real one. If your browser lets you, turn off the feature that sends your e-mail address as a password for anonymous FTP sessions. The File Transfer Protocol, as its name states, is a set of rules that dictates how files should be transferred over the TCP / IP protocol. A basic FTP connection consists of a client and a server.

The client gets a file by opening a connection to the server. Usually, the server is run on port 21, however, the system administrator can change this if he or she wishes. Once the client has connected to the server, the server will send a "greeting" to the client. A greeting usually looks something like the following: 220 Richard's FTP server. Please login! The number before the text is known as a completion code.

The server greeting will be one of two codes: 220 if the server accepts the connection or 421 if the server rejects the connection. After the server has sent its greeting, the client sends a request. A request is made up of a verb and, for some verbs, a parameter. After sending a request, the client should wait for the server to respond before the client sends another request; however, the client can send an ABORT, STAT, or QUIT request without waiting for the server to respond. Typically, after the server has sent the greeting, the client will respond with a USER request in which the client sends the username to log into the FTP server with. After the client has sent the server a request, the server replies with a response.

A response consists of a completion code followed by one, or more, lines. Generally, if the second digit of the completion code is a 0, it is a syntax error message; if the second digit of the completion code is a 2, it is a hello or goodbye message. Once the client is logged in, he or she would then get the file, he or she wishes to retrieve. A typical session would look similar to this: 220 Richard's FTP server.

Please login! USER Richard 331 Username okay. Send password! PASS password 230 Password accepted, user logged in. LIST 150 Opening ASCII mode data connection for / bin / ls 226 Transfer complete TYPE I 200 Type set to I PASV 227 Entering passive mode (206, 84,161, 87, 28, 46) RETR data file. zip 150 Opening BINARY mode data connection for data file. zip 226 Transfer complete When downloading a file, the client should specify whether he wants the file sent in ASCII mode or binary mode.

To set the mode of transfer, the client sends the TYPE request. TYPE I would set the binary mode. By default, binary mode is turned off. It is important that the server send the file in the correct mode to avoid file corruption. When the client sends a PASV request, the server opens a temporary socket and sends a reply to the client, which informs the client of port to connect to.

The reply would look like this: PASV 227 Entering passive mode (206, 84,161, 87, 28, 46) The numbers in the parentheses play an important role. The numbers separated by the first four commas make up the IP address to connect to. In this example, the IP would be 206.84. 161.87. The remaining numbers specify which port to connect to. Now that the server has replied to the PASV request, two channels are open: the first the original one is the communication channel where the requests are sent and the second is the data channel where the data is transferred.

The PORT request is similar to the PASV request, however, when the client sends a PASV request, the server opens another socket, and the client connects to it. When a client sends a PORT request, the server connects to the client-usually on port 20. Now that you know how FTP works, will be good to show you how to log into a server, look around, and then get a file. Before the begin, you should know about anonymous FTP servers. An anonymous FTP server is just like a normal server; however, you can login using the username anonymous and an e-mail as the password. In this example, I will use a fake e-mail of.

Most anonymous FTP servers only read up to the @ sign, so if you are lazy you can just type in guest@. Many sites offer anonymous FTP because it is an easy way to let the public get files without assigning each person a login. On with the example! First, connect to the server and send the username and password. 220 Richard's FTP server. Please login!

USER anonymous 331 anonymous login okay, send e-mail as password. PASS 230 Password accepted, logged in as anonymous. Now that you are in, you will change to the "files" directory and download a file. CWD. /files 250 CWD command successful. TYPE I 200 Type set to I PASV 227 Entering passive mode (210, 52,165,168, 15, 26) RETR code. zip 150 Opening BINARY mode data connection for code. zip 226 Transfer complete You have the file you want, now you will move up to the parent directory, move to another directory, and download another file. CWD...

250 Okay CWD. /jokes 250 CWD command successful. TYPE A 200 Type set to A PASV 227 Entering passive mode (210, 52,165,168, 15, 26) RETR jokes. txt 150 Opening ASCII mode data connection for jokes. txt 226 Transfer complete You got the two files you wanted, so now you will logout. QUIT 221 Goodbye, please come back! Now you should be ready to use your FTP client software and transfer files from and onto the Internet. What is telnet? It is a terminal emulation program telnet emulates crusty old terminals, like the Digital VT-100 and VT-102, for TCP / IP networks such as the Internet.

The Telnet client runs on your computer and connects your PC to a server on the network. You can then enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. This enables you to control the server and communicate with other servers on the network. To start a telnet session, you must connect to a server on an open port and enter a login and password.

How to use Windows 95 telnet? The Windows 95 telnet client can be found in the c: windows directory, do not confuse this with Hyper Terminal. Open it and once loaded you will now be staring at a blank window. if the interface looks boring enough to make you want to quit, then remember that before the days of graphical client programs like email or news clients, web browser's etc, telnet was the only window into the internet. Now, click on "connect" in the menu bar, then "Remote System". You will then be presented with a dialog box that asks for information about the host name or IP address the port and the type of emulation, because the terminal client in your Windows 95 will emulate an older device. A good place for your first telnet connection is your shell account.

A shell account is a Unix terminal. If you have a shell account then you can run apps on the shell and other stuff. To find out if you have a shell account and its URL, check out your ISP's WebPages or email the system administrator. Alternatively, you can try telnetting to an FTP server. Any ISP worth their salt should have an FTP server. This is the telnet equivalent of using an FTP client or web browser to browse an FTP archive.

In the 'Connect' field, type ftp. pig. sk, substitutes your ISP's domain for '. sk'. If your ISP's web-page was at web your domain would be abc. sk, i.e. your ISP's web URL, but without the '. ' In the 'Port' dialog, type the number 21. FTP is bound to port 21. Now click "connect". Once connected, you will presented with a prompt.

This prompt indicates the daemon and often version. A daemon is a program that runs on a remote computer and manages a particular service, i.e. the FTP daemon controls connections to the FTP port and generally manages the FTP side of things. The mail daemon, like 'send mail' for instance, manages things when you send an email and so forth. Ok, so at the prompt, type: user anonym ous but, if it already has a prompt saying something like 'Username' or 'Login', drop the 'user' and type just anonymous, without the 'user' bit. After it says 'guest login accepted', type: pass, once again, if it comes up with a 'Password:' prompt, drop the 'pass' bit and enter only your email address. It will then display some more trivia.

Now you have logged in, type: help this will display all the different commands the FTP server understands. Play around with some commands. Once you have finished playing around with port 21, try a few different ports, like the ones listed below. Your ISP may not offer all of these services, but have a go and use some common sense i.e. you wouldn't try to connect to port 21 on my mail server, nor you would try to connect to port 25 on my FTP server. Also, try telnetting to some servers outside of your ISP, like some anonymous FTP sites.

Now you have some ports to connect to some Telnet server. In the 'Name' field, enter the name of the session '. sk FTP site', 'Shell Account' etc. Then, in the 'Network address' field, enter the IP address or URL of the computer you want to connect. Click Custom then type the port number, default is port number 23. Then select a terminal emulation type from the 'Configuration' field. Hit Ok, click on the session you have just created the configuration.

If you want, more luxury when using telnet clients tries to find these telnet clients at TUCOWS or other software archive web This is a basic intro to telnet. One of the problems with Telnet and FTP is that the user has to know exactly which information can be found on which computer in order to be able to find it. People began to compile directories of network services and made them available electronically. The most important information in such a directory was usually the IP-number and / or Domain-name of a specific information service. Now, that the Internet 'knows' where the requested service resides, why does not it just connect me to it? In recent years programmers noticed these ideas and developed more intelligent Internet services.

These services try to hide unnecessary technical information from the user and let him / her use the Internet as a whole as an information source. A good example of such a service is Gopher. When a user starts his / her Gopher client, it displays a menu for the user to choose from. For each menu item, the client receives a descriptive name, a flag that identifies the type of information, and information about where on the network this information can be found Domain-name, file-name, port number. The client displays only the descriptive name and an identifier for the type of information. This is all the user really needs to know.

When he selects a menu item, the Gopher client connects to the respective computer, retrieves the requested information, and displays it on screen. Because one of the information types can be another Gopher menu, this simple concept yields a very flexible and efficient network service. The user can jump from one Gopher menu to another until he has found the required information. The menu items may refer to another Gopher menu, a plain text file, a binary file, a database inquiry module, a picture, sound, or movie, and even a Telnet host. The items combined in one Gopher menu do not need to point to information on the same computer. A Gopher menu can logically collect related information and displays it to the user as alternatives, even when the information is stored in different parts of the world.

To the user this dispersed information appears as if it were stored in one subdirectory on the hard disk. The user can move from one Gopher server to another and browse the information that is available there. Important elements in Gopher are queries to WAIS databases. The WAIS stands for 'wide area information server'; WAIS cannot be used to its full potential in Gopher. WAIS allows for full-text searches in a set of documents. Because of a database query, WAIS returns pointers to the documents or parts of documents that match the request and indicators for the quality of the match.

Of course, each document can be downloaded and displayed on screen, stored or printed. Each WAIS index that is made publicly available has to have a description of its content. These descriptions are again fed into a WAIS database. This allows the user to query WAIS for publicly available WAIS databases that match specific criteria.

The most sophisticated and most exciting new Internet service is 'World Wide Web' also called. 'The Web' allows everything a user can do with Gopher and WAIS and more with tremendous flexibility. is based on Hypertext links, a concept well known e.g. from the Help system in Microsoft Windows. The main difference is that in Hypertext links may point to documents anywhere on the Internet. When the user activates such a Hypertext link the respective document is retrieved and displayed.

It is important to note that documents can be a number of different text files, pictures, sounds, movies, as well as other Internet services like Gopher, WAIS, Telnet, Netnews, etc. This makes an outstandingly general and flexible Internet tool. When the user follows a Hypertext link and retrieves another document, this new document may contain Hypertext links to other documents with there own Hypertext links, and so on. In this way the user may jump from one document to another and follow an argument the author of the first document has never thought of. The author of a Hypertext document can tie his / her work into an existing network of arguments and link to documents stored somewhere else on the web.

This makes the web particularly attractive for scientific publications, where reference to existing e reference to existing documents is important. In a Hypertext document, a list of references can really come alive. The World Wide Web is a worldwide repository of linked information, called hypertext or hypermedia. It consists of a user interface consistent across many computers and a set of open standards that enables the interface to access a variety of document types and information protocols.

A provision for universal access, based on the Internet domain name schemes. The Internet is a loose federation of networks. Cooperative organization - no administration, no fees. Protocols and standards are evolved through the IETF, Internet Engineering Task Force. Most national and international networks are members: NSF NET, ES NET, ARPANET, and BITNET All these networks are packet switched systems based on TCP / IP. Together these protocols allow for communication over a variety of technologies.

Machines called gateways connect the networks. Nowadays, everyone wants privacy on the web, because no matter where you go, someone could be watching you. Someone like your employer, someone trying to hack your system, companies gathering all your info to sell to yet other companies, or even the government, may be on your track while you peacefully surf the web. Thus, anonymity on the web means being able to use all of its services with no concern about someone snooping on your data. Your computer being connected to the net has an IP [Internet Protocol] address.

If you have a dial-up connection, then your IP changes every time you connect to the Internet but this is not always true, though. There are dial up ISPs, especially for university students, that do have static is. Cable modems and DSL connections have static IP, which means that the IP address does not change. One of the goals of getting anonymous is to make sure your IP, either static or dynamic is not revealed to other users of the Internet, or to server administrators of the servers you roam around when using Internet services. This text tries to give you some hints on how to maintain your anonymity on the web. Some of the hints may sound banal, but think of, if you really abide them in every situation.

When chatting on IRC, ICQ, AIM, do not give out personal information about yourself, where you live, work, etc. Do not use your primary email address the one your ISP gave you anywhere except to family members, close friends, or trusted people. Instead create for yourself a web-based email account such as yahoo, hot mail, dynamite mail, mail. com, etc. and use this e-mail address to signing up for services, when in the need to give your mail to download something, or to publish on your homepage. When signing up for services on the web, do not give your real information like address, telephone number, and such unless you really need to do so. This is the kind of information that information-gathering companies like to get, so that they can sell out and fill your mailbox with spam. Use an anonymous proxy to surf the web.

This makes sure your IP does not get stored on the web-server logs. Web-servers log every GET request made, together with date, hour, and IP. This is where the proxy comes in. They get the IP from the proxy, not yours. Use a bouncer to connect to IRC networks, in case you do not trust the administrators, or the other users.

A bouncer is a program that sits on a permanently connected machine that allows you to connect there, and from there to the IRC server, just like a proxy works for web-servers. Use anonymous re mailers to send out your e-mails. Cryptography can also help you by making sure the material you send out the web, like by email, etc, is ciphered, not allowing anyone that doesn't have your key to read. Programs like PGP (pretty good privacy) are toolkit's with all you need to cipher and encipher your stuff. Delete traces of your work with the computer including history files, cache, or backup files.

Proxies are caches that relay data. When you configure your web browser to use a proxy, it never connects to the URL. Instead it always connects to the proxy server, and asks it to get the URL for you. It works similarly with other type of services such as IRC, ICQ etc. There will not be direct connection between you and the server, so your real IP address will not be revealed to the server. When you view a web-site on the server, the server will not see your IP.

Some of web proxies do not support forwarding of the cookies whose support is required by some of the web-sites. Here are some anonymous proxies that you can use to surf anonymously. Aids - web - web - web Cloak - web You will highly probably find many web-sites that provide the lists of unauthorized proxies and re mailers. Such lists are being compiled usually with the help of port scanners or exploit scanners, scanning for computers with win gate or other proxies' backdoor's. Using these proxies is illegal, and is being considered as unauthorized access of computer. If you get such list to your hands, check if the info is legal or compiled by script, and act accordingly.

If you anyhow decide not to use proxy, at least do not forget to remove your personal information from your browser. After you remove details like your name and e-mail address from your browser, the only info a Web site can sniff out is your ISP's address and geographical location. In addition, Java and JavaScript applets can take control of your browser unexpectedly, and if you are surfing to unknown and potentially dangerous places, you should be aware of that. There are exploitable browser bugs reported ever week. As we all work hard to become well informed about protecting our personal information and keeping as anonymous as possible on the web, advertising companies are working just as hard to come up with new ways of getting our personal information. One of the ways they accomplish this is through spy-ware.

Spy-ware is applications that are bundled along with many programs that you download free. Their function is to gather personal information about you and relay it back to advertising firms. The information is then used either to offer you products or sold to other advertisers, so they can promote THEIR products. They claim this is all they do with this information, but the problem is nobody really knows for sure. Spy-ware fits the classic definition of a Trojan, as it is something that you did not bargain for when you agreed to download the product. Not only is spy-ware an invasion of your privacy, but especially if you have a few different kinds on your machine it can also chew up bandwidth, making your Internet connection slower.

Sometimes, these spies really are harmless, merely connecting backs to the home server to deliver you more advertising. Some, like Gator for instance, send out detailed information about your surfing habits, operating system, and income, age demographic et cet era. Avoiding spy-ware is getting harder and harder, as more software distributors are choosing it as a method of profiting from freeware and shareware distributions. Be leery of programs with cute little icons like Gator. Also, watch those Napster wannabes like Audio Galaxy, Limewire, and Kazaa. I have yet to find one that did not include spy-ware.

Before you download, check to see if the program is known to contain spy-ware. In most cases, you can remove the spy-ware from your system and still use the application you downloaded. In the case of Gator and Comet Cursor, the whole program is spy-ware and it must be completely removed to stop the spying. There are several ways to get rid of spy-ware on your system. You can use a firewall to monitor outgoing connections.

The programmers that put these things together, however, are getting sneakier and sneakier about getting them to circumvent firewalls. Comet Cursor, for instance uses an HTTP post command to connect without the intervention of a firewall. You can also install a registry monitor such as Region to monitor your registry for unwanted registry registry changes, but this is not foolproof either. Probably the best method of removal is to download a spy-ware removal program and run it like it was a virus scanner. The best examples of these programs are: Lavasoft's Adaware.

Available at web or professional cybernaut Steve Gibson's Opt Out. Available at: web both of these programs are free and are updated regularly. Here are some links, if you wish to learn more about spy-ware: web The illegal stuff. 1.

Cheating the pay-sites. 2. Hacking software. 3. Downloading pirated applications and games. 4.

Ordering books and music CD's with generated credit card. 5. Reading other people e-mail. 6. Spying other people on the Internet.