Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. TCP/IP Applications Chapter 9

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Describe common Transport and Network layer protocols Explain the power of port numbers Define common TCP/IP applications such as HTTP, HTTPS, Telnet, SSH, (SMTP, POP3, and IMAP4), and FTP Objectives

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Historical/Conceptual Transport Layer and Network Layer Protocols

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. TCP over IP consists of many other things – HTTP – DHCP – POP – 500 more terms over TCP – UDP over IP – ICMP over IP Transport Layer and Network Layer Protocols

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Connection-oriented communication – Acknowledgement between two people beginning a conversation – Conduct the communication – Close the communication How People Communicate

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Connectionless communication (UDP) – No opening acknowledge – Short message is shouted across a room – No closing Session – Any single communication between computers – All sessions must begin and end How People Communicate (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Test Specific TCP

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Enables connection-oriented communication Most common type of session in a TCP/IP network Transmission Control Protocol (TCP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Client sends a SYN (synchronize) packet to the Web server One computer (Server) returns a single SYN, ACK (synchronize/acknowledge) packet Client sends a single ACK packet and requests that Server begin sending the Web page After the Web page is sent, Server sends a FIN (finished) packet Three-Way Handshake Communication Process

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Client responds with ACK and sends its own FIN packet Server responds with ACK Both parties consider the session closed Three-Way Handshake Communication Process (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.1 A connection-oriented session starting

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.2 A connection-oriented session ending

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Used by very few applications Requires much less overhead than TCP – No start, no acknowledgement, no end Example of application using UDP: DHCP – Each step of a DHCP session sends information without any confirmation User Datagram Protocol (UDP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.3 DHCP steps

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Network Time Protocol (NTP) Simple Network Time Protocol (SNTP) Both synchronize the clocks of devices on a network Uses port 123 NTP/SNTP

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Uses UDP Transfers files between computers Does not have any data protection Never use it over the Internet Best use: between computers on the same LAN Uses port 69 Trivial File Transfer Protocol (TFTP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Works at layer 3 to deliver connectionless packets Handles issues such as disconnect messages Ping is an ICMP application Internet Control Message Protocol (ICMP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Sends a single ICMP packet called an echo request to a specified IP address – All computers (unless blocked by a firewall) respond with echo reply – Responses Destination host unreachable Request timed out – Early version had a bug that allowed ‘ping of death’ to crash the recipient computer ping

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.4 ping in action

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Used for multicasts – Routers use to determine a group membership Multicast – Uses a small subnet of the Class D range – Does not assign IP addresses – Group assigned /4 address – Those who wish to receive multicast must join the IGMP group Internet Group Management Protocol (IGMP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.5 IGMP in action

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. The Power of Port Numbers

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Every TCP/IP application requires a server and a client Clearly defined port numbers exist for popular and well-known applications Well-known port numbers from 0 to 1023 reserved for specific applications The Power of Port Numbers

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.6 HTTP ACK packet

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.7 Dealing with the incoming packet

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. The Web client’s source port number is generated by the Web client computer Ephemeral port numbers – Operating systems assign values 1024 to 5000 – IANA recommends using only ports to Dynamic or private port numbers – Values to The Power of Port Numbers (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.8 A more complete IP packet

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.9 Returning the packet

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved to Less-common TCP/IP applications register their ports with IANA Most operating systems avoid registered port numbers for ephemeral ports – Dynamic/private ports are used instead Registered Ports

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved Well-known port numbers Registered ports Dynamic or private ports

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Both computers keep track of the status of the communication – Session information is held in RAM – Socket or endpoint: one side’s session information – Socket pairs or endpoints refer to data each computer stores about the connection – Session or connection refers to the connection in general Using Ports in a Session

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Source and destination for one session Many simultaneous sessions Use netstat –n to see sessions – Usually shows many connections – TCPView for Windows: dynamic – Net Activity Viewer for Linux Endpoint Information

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.10 Two open windows

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.11 TCPView in action

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.12 Net Activity Viewer in action

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Connection states change continually Open port or listening port – Socket prepared to respond to any IP packets destined for that socket’s port number Every serving application has an open port A Web server will have open port 80 Connection Status

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. netstat –an shows all listening ports on a computer Results of running netstat -an – Active connections – Protocol – Local address – Foreign address – State Connection Status (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Assigned to every running program on a computer – The –o switch with netstat shows the PID Used by the OS to track running programs Commands to provide program name – netstat –b (Windows) and ps (Linux) Windows Task Manager shows all running processes Process ID (PID)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.13 Process Explorer

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Memorize a bunch of common ports Learn how to use netstat Learn the ports and processes that normally run on your operating system Research unrecognized processes Get rid of bad processes Rules for Determining Good vs. Bad Communications

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Common TCP/IP Applications

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Web servers – Store HTML documents – Latest version: HTML5 Web browsers request HTML pages from Web servers and open them – Can use IP address or text address The World Wide Web

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.14 My wireless access point’s Web interface

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.15 HTML5 source code

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Underlying protocol of the Web – Runs by default on TCP port 80 – Places at beginning of Web server address A general weakness of HTTP – Relays commands without reference to any previous commands Hypertext Transport Protocol (HTTP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Other technologies that enhance HTTP – JavaScript/AJAX – Server-side scripting – Adobe Flash – Cookies HTTP (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. A Web server will “host” an HTML document Methods – Self-host Install Web server software and acquire a public IP address Time-consuming and challenging – Host through an Internet Service Provider (ISP) – Use a Web hosting service company – Free Web hosting (nothing is free) Publishing Web Pages

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. A Web server delivers Web pages to client computers – Listens on port 80 for HTML requests – Fetches and sends requested HTML pages To create a Web server – Install Web server software – Connect the computer to the Web Web Servers and Web Clients

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Microsoft Internet Information Services (IIS) – 20-connection limit on client versions of Windows – IIS only runs on Server versions of Windows Apache HTTP Server – Used by the majority of UNIX/Linux systems – Approximately 50 percent of Internet Web servers – Free – Add-on GUIs (e.g., Webmin) are available Web Server Software

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.16 IIS in action

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.17 Webmin Apache module

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Web server software market share – Apache is the most common on the Internet – nginx ranked second for active sites – IIS has about 11 percent share – Google Web Server (GWS) Only used by Google servers – Hundreds of other Web servers primarily for small personal Web sites Web Server Software (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Request and display Web pages Many have multiple functions Most popular: – MS Internet Explorer (IE) – Mozilla Firefox – Apple Safari – Opera – Google Chrome Web Client Software (Browsers)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. HTTP is not secure Requirements for secure Internet applications – Authentication – Encryption – Nonrepudiation SSL and HTTPS offer security Secure Sockets Layer (SSL) and HTTPS (Hypertext Transfer Protocol over SSL)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Developed by Netscape Uses public key to encrypt information Sends encrypted data over an SSL connection The receiving end decrypts using a private key Supported by Web browsers and servers Many Web sites use SSL for confidential data Look for HTTPS or a small lock icon in browser Secure Sockets Layer (SSL)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Uses TCP port 443 Being replaced by Transport Layer Security (TLS) – Functionally the same with Web pages – TLS is covered more in Chapter 11 HTTP Over SSL (HTTPS)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.18 Secure Web page

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Telnet allowed dumb terminals to connect to more than one mainframe Run commands as if sitting at the mainframe Uses port 23 Telnet server access requires logon with user name and password, but has no encryption Secure Shell (SSH) replaced Telnet providing data encryption and authentication Telnet and SSH

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.19 WANG dumb terminal

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.20 Telnet client

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. telnetd: oldest Telnet server Windows comes with a basic Telnet server – Disabled by default Third-party server example: freeSSHd All popular, modern Telnet servers are also SSH servers Third-party Telnet/SSH client example: PuTTY Telnet/SSH Servers and Clients

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.21 freeSSHd

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.22 OS X Telnet

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.23 PuTTY

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. When configured, you must provide: – The host name – A valid login name – The password Open systems provide the password when the login name is given or require no login/password Configuring a Telnet/SSH Client

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. With SSH, both logins and data transmittals are encrypted – Must have permission to access the server SSH uses port 22 SSH and the Death of Telnet

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Major part of the Internet revolution – Has streamlined the junk mail industry – Provides a quick way for people to communicate – Sends messages and attachments – Normally offered as a free service by ISPs Most clients have simple text editors – Many can be configured to use more sophisticated editors Electronic Mail ( )

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Incoming messages are stored on the server – Most clients notify you when new message arrives, or download automatically – You manage messages (archive, forward, print, delete, and more) – Most programs delete downloaded messages from the server (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. SMTP POP3 IMAP4 Application-level Protocols

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Used to send Travels over TCP port 25 Used by clients to send messages Simple Mail Transfer Protocol (SMTP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. One of two protocols used to retrieve from SMTP servers Uses TCP port 110 POP3 use is declining in favor of IMAP4 Post Office Protocol Version 3 (POP3)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Alternative to POP3 Retrieves from an server Uses TCP port 143 Supports features not supported by POP3 – Search messages by keyword – Select messages before download Supports folders on IMAP4 servers Internet Message Access Protocol Version 4 (IMAP4)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Web-based – Access your from anywhere – Free – Handy for throw-away accounts Proprietary solutions Alternatives to SMTP, POP3, and IMAP4

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.24 Gmail in action

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. The server market is fragmented Sendmail for UNIX/Linux is leader (SMTP only) – No GUI interface; third-party interfaces (Webmin) – Controls about 20 percent of servers – Must use a POP3 or IMAP server program to support clients Eudora’s Qpopper sends mail to POP3 clients Servers

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.25 Webmin with the sendmail module

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Microsoft Exchange Server (both SMTP and POP3) – Only runs on Windows Mailboxes: holding areas on mail server for each user’s messages – Server arranges incoming messages – Server returns messages with unknown recipient – Difficult to manage Servers (cont’d.)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.26 Microsoft Exchange Server

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Enables you to send, receive, and organize Communicates with: – SMTP server to send – IMAP or POP3 server to download messages Hundreds of client programs – Microsoft Outlook – Mozilla Thunderbird Client

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.27 Microsoft Outlook

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Obtain the server’s domain name and your mailbox user name and password Enter the POP3 or IMAP4 server’s domain name and the SMTP server’s domain name Enter the user name and password of the account Configuring an Client

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.28 Entering server information in Microsoft Outlook

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. The original Internet file transfer protocol Faster and more reliable than HTTP Includes security and data integrity TCP ports 20 and 21, by default Anonymous or secured sites – Some are both File Transfer Protocol (FTP)

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Store files Accept incoming connections Verify user names and passwords Transfer files Easy to set up Most versions of Linux/UNIX have built-in FTP servers; many third-party servers offer better solution FTP Servers

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.29 FileZilla Server

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Data transfers are not encrypted by default – Add usernames and passwords to provide some level of protection Determine the number of clients you wish to support – Most anonymous FTP sites limit the number of users to 500 FTP Is Not Very Secure

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. You can access FTP servers many ways – Web site – Command line – FTP client applications Some Web browsers support FTP, but lack features Dedicated FTP clients work best – FileZilla client; Mozilla FireFTP add-on to Firefox FTP Clients

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.30 FTP in a Web browser

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Figure 9.31 Author’s FireFTP hard at work

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved. Traditional FTP uses active process – Clients send an FTP request on TCP port 21 – Server responds on an ephemeral destination port with TCP port 20 as the source port Passive FTP server works with NAT – Client sends an FTP request on TCP port 21 – Server sends back a random listening port number; client sends data to that port Active versus Passive FTP

Mike Meyers’ CompTIA Network+ ® Guide to Managing and Troubleshooting Networks, Fourth Edition (Exam N ) Copyright © 2015 by McGraw-Hill Education. All rights reserved.