2 Overview Understand the e-mail environment Understand e-mail protocols Administering the Microsoft Exchange 2000Installation and administering sendmail for LinuxInstall and configure IMAP4 and POP3 servers for Linux
3 Understanding the E-mail Environment evolved from a variety of proprietary systemsIn the 1980s and 1990s, people often had addresses on a number of systemsEven as late as 1997, many servers were not able to take advantage of InternetMost common server productsSendmail (Linux)Exchange (Windows)
4 Exchange 2000 Goes Beyond E-mail Basics Instant messagingUnified messaging platformSingle inbox for , voic , faxChat serviceURL addressingUse a single URL to access stored dataAudio and video conferencingWhat about the goofy cartoons (emotions) you can include in your ?
5 Role of DNS in E-mail Systems Sending messages requires configuring DNSA domain name, such as technowidgets.com, needs to be associated with two IP addressesOne IP address can be for a Web siteAnother IP address is forTo associate a domain name, or any other host name, with the IP address of an server, you need a mail exchange (MX) recordtechnowidgets.com. IN MX 10 mail.technowidgets.com.The 10 refers to the priority of the server if there are multiple serversIN indicating the domain nameMX representing a Mail Exchange (MX) record – other options could be A or NS
6 E-mail System Terminology MTA (Mail Transfer Agent)Accepts from clients and sends to another MTA for storageExchange 2000, sendmailMUA (Mail User Agent)client softwareFormats the message and prepares it for sending to MTAOutlook, KMailMDA (Mail Delivery Agent)Part of the serverDelivers from server to MUAExchange 2000, imap-2001
7 E-mail System Terminology MasqueradingReplace actual host name with domain nameActual host name is replacedmail2.technowidgets.com mail2.technowidgets.com becomes technowidgets.com (masking the full host name)RelayingThe process of sending to an intermediate server (MTA) before the message is transmitted to its final destinationWhen single MTA is available, relaying should not be allowed from the Internet because spammers could use it to send
8 E-mail Protocols SMTP (Simple Mail Transfer Protocol) Text-based protocol used to send messagesDoes not concern any concerns about securityBoth client and server use itPOP3 (Post Office Protocol)To retrieveclient uses it to read, list, and delete messagesTypically, all messages are downloaded to a clientIMAP4 (Internet Mail Access Protocol)More complex than POP3stays on the server and can be retrieved from any computer that has an client and supports the protocolYou can create folders on server to store
9 Understanding SMTP The commands are processed by the SMTP server PurposeHELOIdentifies the domain sending the messageDATAIndicates the body of the messageVRFYVerifies the userQUITEnds the SMTP session
10 Understanding SMTP The SMTP headers add descriptive information Header DescriptionMAIL FROM:Identifies who is sending the message (required)RCPT TO:Identifies the recipient of the message (required)RECEIVED:Identifies the server that processed the messageDATE:Indicates the date of theFROM:Shows the address as it is typically displayed in an clientSUBJECT:Shows the subject of the messageTO:Shows the recipient as it is typically displayed in an clientCC:Sends copies of the message to a list of addressesBCC:Sends copies of the message to a list of addresses but does not display the addresses
11 Understanding SMTP Sample session (commands and headers) HELO WKS1 Sending the name of the host250 web1.technowidgets.com Hello [ ]MAIL FROM:OKRCPT TO:DATA354 Start mail input; end with <CRLF>.<CRLF>This is a simple message.QUITResponse CodeCarriage ReturnLine feed
12 Understanding POP3 Less complex than IMAP4 First step is to logon with user name and passwordList, read, download, delete
13 Common POP3 commands Command Description USER username Connects to POP3 server based on user namePASS passwordEnters the password for the user, as in PASS: Ax6yyLISTDisplays the message number followed by the number ofcharacters in the messageUIDLDisplays the unique ID for each messageRETR nReplaces the n with a message number to retrieve that messageTOP n linesInstead of retrieving the whole message, retrieves the number oflines designated by the lines parameter for message number nDELE nDeletes message number n from the serverQUITEnds the session
14 Understanding IMAP4 Messages remain on server Requires much more space on serverTo keep track of the status of messages, flags are used (For example your free yahoo account)\Recent\Seen\Answered\Flagged\Deleted\Draft
15 Common IMAP4 commands Command Description LOGIN username password Log on to the server with your user name and password, which are unencrypted.SELECT mailboxSelect a mailbox before you perform mail tasks. The default mailbox is called inbox. The response gives a summary of mailbox information.FETCH message(s) item(s)Retrieve messages. The message(s) parameter gives the message number. The item(s) parameter determines what part of the message is fetched—that is, individual header items or the body of the text.STORE message(s) flagsChange the flags associated with a message. Typically, this command is used to mark messages to be deleted, undeleted, or identified as unread.LOGOUTEnd the IMAP4 session.
16 Installing Microsoft Exchange 2000 Install SMTP is part of IIS Web ServerInstall NNTP (Network News Transport Protocol), also a part of IISUsed for newsgroupActive Directory is required for ExchangeOnce the above are installed, the Exchange wizard guides you through a simple installationThen, to use Exchange 2000 on Windows Server 2003, install Exchange 2000 Service Pack 3 is required
17 Installing and Configuring Sendmail for Linux Installed sendmailincludes SMTP onlyConfigure sendmail through a macro called m4m4 /etc/mail/sendmail.mc >/etc/mail/sendmail.cfThe macro is processed and sendmail.cf is createdThere are many advanced features of sendmail that make configuring it substantially difficultThere are other servers, such as qmail, that are easier
18 Minimal sendmail.mc File divert(-1)include(`/usr/share/sendmail-cf/m4/cf.m4')OSTYPE(`linux')define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnlFEATURE(local_procmail,`',`procmail -t -Y -a $h -d $u')dnlMAILER(smtp)dnlMAILER(procmail)dnlCwtechnowidgets.comNotice that the strings are enclosed with a backtick and an apostrophe as in `linux'
19 Configuring E-mail Clients- Typical Information Required SMTP server IP addressYour addressYour passwordPOP3 or IMAP4 server IP address
20 Summary E-mail has evolved over the years Microsoft Exchange 2000 and sendmail are the two of the most popular server productsDNS plays a central role in messagingThree major protocols are involved inSMTP, POP3, and IMAP4
22 Linux Projects Project 8-1 Project 8-2 Project 8-5 Project 8-7 Make sure your DNS worksGo to page and make sure you have added the two entries in your reverse lookup tableMake sure sendmail is installed: You should have checked the mail server boxIf you have to install it, there is no need to Start the programYou should have a /etc/mail/sendmail.mc file. Make a back up of this file and modify it according to the text page 424Using m4 utility create sendmail.cf page 424 step 5Create a telnet session to sendtelnet localhost 25 send a message toDo cat /var/spool/mail/ you should see the messageProject 8-2Test IMAP4/POP3telnet localhost 143 Results must be similar to Page 428telnet localhost 110 Results must be similar to Page 429Project 8-5Configure Kmail in Linux – create two users and send s to each otherProject 8-7Do cat /var/spool/mail display all the messages (header and contents) the user has receivedTwo servers should be able to send messages to each other!
23 Windows Lab Do project 8-9 page 437 Send from a Linux server to a Windows machine.If you Install Exchange 2000, and do you will receive Extra credit!Page 389- Installation steps!Page 392-AdminsteringProject 8-3 page 429
24 Homework (April. 5rd) - submit through WebCT How can you access your by using a browser in Linux? (Read chapter 8 pages ; in Windows Web-based product is OWA (Outlook Web Access). OWA uses XML or Dynamic HTML to transfer format processing from the server to the browser). Is there a similar capability in Linux? Is there a software to support Webmail for Linux? Are there software products that allow transferring format processing from the server to the browser? )Extra Credit - Write a step-by-step procedure to install a software product in Linux that allows webmail.What is qmail in Linux? Can we use it instead of sendmail? What is it used for?Extra Credit – Implement qmail on a server in the lab or write a step-by-step procedure. (Do not copy the procedure from the Web – I have already read that! To get extra credit, you should write your own SHORT version)Find a Linux-based package that can be configured to allow instant messaging, (or audio and video conferencing). What is the difference between Gaim and Kopete?What is multicasting? What is source tree multicasting? Does server utilizes multicasting? How?One way spammers send unsolicited is by masquerading their message such that they appear to have come from your organization or some safe source. Elaborate on such spamming techniques. What do they do so that you cannot detect them? (Read about spamming technique. There are lots of ways to send spam and not get detected – There are many interesting articles about this in PCWORLD.com – Don’t just copy and paste – I have read them! Just write a brief summary)Let me know if you find errors in the book!Maximum Extra Credit will be 20 points
26 Linux Email Server Labs Install sendmail (page 400 step 1-9)Configure the sendmail as sendmail.mc and store it in >/etc/mail/Install and configure IMP4 and POP3 (page 404)Configure client in Linux: Kmail installed automatically – create an accountIf you have problem with Kmail you may need to reinstall Kmail