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The University of Akron Summit College Business Technology Dept. 2440: 141 Web Site Administration Remote Web Server Access Tools Instructor : Enoch E. Damson. Web Environment Servers. Some servers you can access remotely include: File Transfer Protocol (FTP) servers
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The University of AkronSummit CollegeBusiness Technology Dept. 2440: 141Web Site Administration Remote Web Server Access Tools Instructor: Enoch E. Damson
Web Environment Servers • Some servers you can access remotely include: • File Transfer Protocol (FTP) servers • Network News Transfer Protocol (NNTP) servers • Telnet • Streaming Media Servers Remote Connection to Web Servers
Running An FTP Server • File Transfer Protocol (FTP) • Used to shares files between networked computers • Client and server programs available for all platforms • FTP has been integrated into modern Web browsers • Anonymous FTP • Current primary use of FTP • Allows access to FTP server without account • FTP servers may be set up to restrict file access • Users authorized to access files are "known" Remote Connection to Web Servers
FTP Client/Server Interactions • FTP utilizes two ports: • Control port (port 21) – serves as a communication channel between the client and the server for commands/replies exchange • Data port (port 20) – used purely for the data exchange • FTP can operate in two modes: • Active FTP – the FTP client does not make actual data connection to the server • The client informs the server of its own port with a port command • Passive FTP – the FTP client issues a pasv command to indicate that it wants to access data in passive mode Remote Connection to Web Servers
Using an FTP Client • Required for accessing an FTP server • FTP clients may be text-based or graphical • Accessing an anonymous FTP server with ftp • Specify the server name after the ftp command • Example: ftp ftp.ibiblio.org • A username and password may be needed • Enter anonymous as username • Enter e-mail address as a password • Following logon, ftp> prompt appears • Enter commands to interact with the FTP server • Enter bye to exit Remote Connection to Web Servers
Using an FTP Client… • Using a Web browser to access FTP sites • Point browser to ftp server • Example: ftp://ftp.hq.nasa.gov • Browser logs on to FTP server • Uses anonymous as username • Uses e-mail address as password • Browser creates HTML pages and file listings on the fly • Manipulate displayed files using mouse • Logging on to an FTP server with a user account • Provides greater access to features of FTP service • FTP administrator may still restrict activities Remote Connection to Web Servers
Using an FTP Client… • There are several FTP clients available • One of the clients installed on the Fedora core is: • gFTP: FTP specific graphical client Remote Connection to Web Servers
FTP Servers • Some FTP servers include: • vsftpd (very secured ftp daemon) • wu-ftp: Washington University FTP server Remote Connection to Web Servers
FTP Servers… • Three types of FTP users • Anonymous: use ftp or anonymous as logon name • Real: use a regular Linux user account • Guest: use restricted regular user accounts Remote Connection to Web Servers
Setting Up FTP Configuration Files… • Define user classes to assign permissions by group • Example of class including all three FTP user types • class office real, guest, anonymous 192.168.100.0/24 • All users logging on from given address are in office • Define message files for screen display • Contents automatically displayed by FTP server • Controlling file actions permitted to FTP user • Use series of directives naming file action • Follow directive with yes or no • Include class of user to which directive applies Remote Connection to Web Servers
Understanding News Servers • News servers allow threaded discussions • You post messages in a newsgroup • A newsgroup focuses on a single topic • There are several public newsgroups available • There are hundreds of gigabytes of information generated per day • News servers can be set up for use within an organization
Telnet and Windows • Telnet is not popular in Windows because telnet is text-based and Windows relies on a GUI • However, there are many command-line utilities that can be used • Before Windows, Microsoft networking depended on a single command net with many options • cacls can be used to alter permissions • netsh starts a networking shell which allows you to configure and display many network-related items
Understanding Streaming Media Services • Used to transfer video and audio • By default, UDP is used • Although TCP and HTTP can be used because of firewall issues in an organization • No single standard exists • Broadcast methods • unicast – each packet is sent individually to each client • multicast – each packet is sent to many clients
Understanding E-Commerce Servers • Can be as simple as a product list and a shopping cart • Can be as complex as amazon.com • Microsoft Commerce Server is an add-on to IIS • Incorporates a number of features required for a typical e-commerce site • Highly customizable