Web Server Administration Chapter 9 Extending the Web Environment

Overview Understand File Transfer Protocol (FTP) services Install and configure an FTP server in Windows Install and configure an FTP server in Linux Understand News servers Configure remote access to a server Understand streaming media servers Understand e-commerce software

Understanding FTP Services FTP is used to transfer files from a server to a client (download) and transfer files from a client to a server (upload) FTP client is the browser Also command-line and GUI clients FTP servers can operate as anonymous servers or they can require a valid logon Typically, they are anonymous FTP servers are not secure; user names and passwords are not sent encrypted

Understanding FTP Services The client connects to port 21 (control port) Port 20 (data port) is used to tell the client which unprivileged port to use for data transfer The above describes passive mode FTP, the most common type

Communicating with FTP Command Description Example ftp host Initiates a connection to FTP server ftp 192.168.0.100 open host Once the FTP client has been started, opens a connection open 192.168.0.100 close Closes the connection but does not exit the FTP client quit or bye Closes the connection and exits the FTP client bye ls filenames Displays filenames and can use wildcards ls *.rpm dir filenames Displays the long listing of files and their properties, such as the size and date the file was created dir *.rpm

Communicating with FTP Command Description Example binary Transfer files in binary mode ascii Transfer files in text mode get filename Downloads a single file get test.rpm put filename Uploads a single file put testapp.zip Mget filenames Downloads multiple files; used with wildcards mget sendmail*.rpm mput filenames Uploads multiple files; mput *.tif prompt no Stops prompting for each file when used before you use mget or mput prompt Starts prompting

Communicating with FTP Command Description Example hash Displays a hash symbol as files are being downloaded cd directory Moves to another directory on the FTP server cd /software lcd directory Moves to another directory on the client lcd /docs pwd Displays the current directory on the server help command Finds very brief help on FTP commands; if used without a reference to a command, it will give you a list of commands available help mget

Install and Configure Windows FTP Server Windows component Part of IIS Configured through Internet Information Services (IIS) Manager

Configure FTP Messages Banner appears when client connects Welcome appears when logged on Exit appears when client exits from server Maximum connections appears when limit is reached and client cannot connect

Install FTP in Linux The wu-ftpd FTP server was developed by Washington University Once the rpm is installed, enable FTP chkconfig wu-ftpd on Restart xinetd service to recognize change service xinetd restart

Configure /etc/ftpaccess The /etc/ftpaccess file is the main configuration file By default, users with IDs less than or equal to 99 are not allowed They are for system users and daemons Because the ftp user is a system user, you have to allow it with allow-uid ftp allow-gid ftp

Configure /etc/ftpaccess Limit user to a maximum of five failed logons before a disconnect loginfails 5 Check for password that conforms to e-mail address passwd-check rfc822 warn

Control Access Set up user classes Set limits for class class all real,guest,anonymous * class local real 192.168.0.0/24 Set limits for class file-limit out 25 anonymous file-limit in 10 local byte-limit out 2000000 anonymous

Configure Messages To receive notice that a readme file exists at login or any current working directory (cwd) readme README* login readme README* cwd=* To display a message when a user logs on or moves to a directory message /welcome.msg login message .message cwd=* To create a banner message when client connects banner /etc/banner.txt

Understanding News Servers News servers allow threaded discussions You post messages in a newsgroup A newsgroup focuses on a single topic There are more than 40,000 public newsgroups There are hundreds of gigabytes of information generated per day News servers can be set up for use within an organization

Configuring Telnet in Linux By default, telnet is installed but not enabled chkconfig telnet on service xinetd restart Telnet should not be used in a non-secure environment such as over the Internet because user names and passwords are not encrypted ssh is a secure replacement (described in Chapter 10) You cannot log on as root However, you can log on as another user and "su root"

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, especially in Windows Server 2003 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

Common net Commands Command Description Example net user Lists all users net user username Displays user information net user mnoia net start service Starts a service net start "FTP Publishing Service" net share name=location Shares a folder net share docs=c:\docs net use drive: \\computer\share Maps a drive net use g: \\web1\docs

cacls options The format is: cacls file or folder name [options] Description /e Changes instead of replaces permission /t Changes all subfolders /g user:perm Grants a user specific permissions Permissions are: f (full control) r (read) w (write) c (change) n (none) /p user:perm As above, except permissions are replaced /r user /e Revokes permission

netsh Examples Create a text file with commands to re-create the IP configuration netsh interface ip dump Ping the gateway IP address of each NIC netsh diag ping gateway In Windows Server 2003 Display errors in system log Manage network monitor and performance Defragment a drive Shut down a server

Terminal Services in Windows GUI-based access to a server Can be used for remote administration or running applications remotely In Windows 2000, you select remote administration on installation In Windows Server 2003, it is installed already and you have to enable it Client software is included in Windows Server 2003 and Windows XP You have to install client software for Windows 2000

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 as is true with SMTP, HTTP, POP3, and others Broadcast methods unicast – each packet is sent individually to each client multicast – each packet is sent to many clients

Understanding Streaming Media Services Helix Universal Server from Real Networks is popular Recognizes both Real Networks protocols (RTSP, PNA) and the Microsoft protocol (MMS) Windows Media Services is a Windows component Creates a folder called \ASFRoot to store Advanced Streaming Format (ASF) files

Understanding E-Commerce Servers Can be as simple as a product list and a shopping cart Can be as complex as amazon.com or dell.com Microsoft Commerce Server is an add-on to IIS Incorporates a number of features required for a typical e-commerce site Highly customizable

Summary Use FTP to transfer files You use News servers to set up threaded discussions on a variety of topics Telnet and Windows Terminal Services allow you to remotely administer a server Streaming media servers are used for video and audio E-commerce servers focus on selling and in general, communicating with customers