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    1: # Mail and news
    3: This chapter explains how to set up NetBSD to use mail and news. Only a simple
    4: but very common setup is described: the configuration of a host connected to the
    5: Internet with a modem through a provider. You can think of this chapter as the
    6: continuation of
    7: [[Setting up TCP/IP on NetBSD in practice|guide/net-practice]], assuming a
    8: similar network configuration. Even this *simple* setup proves to be difficult
    9: if you don't know where to start or if you've only read introductory or
   10: technical documentation. A general description of mail and news
   11: configuration is beyond the scope of this guide; please read a good Unix
   12: Administration book (some very good ones are listed on the NetBSD site).
   14: This chapter also briefly describes the configuration (but not the usage) of two
   15: popular applications, mutt for mail and tin for news. The usage is not described
   16: because they are easy to use and well documented. Obviously, both mutt and tin
   17: are not mandatory choices: many other similar applications exist but I think
   18: that they are a good starting point because they are widely used, simple, work
   19: well and don't use too much disk space and memory. Both are console mode
   20: programs; if you prefer graphics applications there are also many choices for X.
   22: In short, the programs required for the configuration described in this chapter
   23: are:
   25:  * postfix
   26:  * fetchmail
   27:  * mutt
   28:  * tin
   30: Of these, only postfix is installed with the base system; you can install the
   31: other programs from the NetBSD package collection, pkgsrc.
   33: *Note*: Since NetBSD 4.0, postfix is the default MTA (Mail Transport Agent) and
   34: sendmail was removed. Also, because sendmail is widely popular and several
   35: programs like fetchmail are designed to be used with it, postfix includes a
   36: command line wrapper that accepts sendmail's commands line syntax but works with
   37: postfix. See
   38: [sendmail(1)](
   39: for more details.
   41: Before continuing, remember that none of the programs presented in this chapter
   42: is mandatory: there are other applications performing similar tasks and many
   43: users prefer them. You'll find different opinions reading the mailing lists. You
   44: can also use different strategies for sending and receiving mail: the one
   45: explained here is only a starting point; once you understand how it works you'll
   46: probably want to modify it to suit your needs or to adopt a different method
   47: altogether.
   49: At the opposite extreme of the example presented here, there is the usage of an
   50: application like Mozilla, which does everything and frees you from the need of
   51: configuring many components: with Mozilla you can browse the Internet, send and
   52: receive mail and read news. Besides, the setup is very simple. There is a price
   53: to pay, though: Mozilla is a "closed" program that will not cooperate easily
   54: with other standard Unix utilities.
   56: Another possibility is to use emacs to read mail and news. Emacs needs no
   57: introduction to Unix users but, in case you don't know, it is an extensible
   58: editor (although calling emacs an editor is somewhat reductive) which becomes a
   59: complete work environment, and can be used to read mail, news and to perform
   60: many operations. For many people emacs is the only environment that they need
   61: and they use it for all their work. The configuration of emacs for mail and news
   62: is described in the emacs manual.
   64: In the rest of this chapter we will deal with a host connected to the Internet
   65: through a PPP connection via serial modem to a provider.
   67:  * the local host's name is `ape` and the internal network is ``,
   68:    which means that the FQDN (Fully Qualified Domain Name) is ``.
   69:  * the user's login name on ape is `carlo`.
   70:  * the provider's name is BigNet.
   71:  * the provider's mail server is ``.
   72:  * the provider's news server is ``.
   73:  * the user's (`carlo`) account at the provider is `alan` with the password
   74:    `pZY9o`.
   76: First some basic terminology:
   78:  * *MUA (mail user agent)* -- a program to read and write mail. For example:
   79:    mutt, elm and pine but also the simple mail application installed with the
   80:    base system.
   82:  * *MTA (mail transfer agent)* -- a program that transfers mail between two host
   83:    but also locally (on the same host). The MTA decides the path that the mail
   84:    will follow to get to the destination. On other BSD systems (but not only)
   85:    the standard MTA is sendmail, other examples are qmail, exim and Microsoft
   86:    Exchange.
   88:  * *MDA (mail delivery agent)* -- a program, usually used by the MTA, that
   89:    delivers the mail; for example, it physically puts the messages in the
   90:    recipient's mailbox. For example, postfix uses one or more MDAs to deliver
   91:    mail, and procmail is another well-known MDA.
   93: The following figure depicts the mail system that we want to set up. Between the
   94: local network (or the single host) and the provider there is a modem PPP
   95: connection. The *bubbles* with the thick border (postfix, fetchmail, mutt) are
   96: the programs launched manually by the user; the remaining bubbles are the
   97: programs that are launched automatically. The circled numbers refer to the
   98: logical steps of the mail cycle:
  100: ![Structure of the mail system](/guide/images/mail1.gif)
  102:  1. In step (1) mail is downloaded from the provider's POP server using
  103:     fetchmail, which hands messages off to postfix's sendmail wrapper to put the
  104:     messages in the user's mailbox.
  106:  2. In step (2) the user launches mutt (or another MUA) to read mail, reply and
  107:     write new messages.
  109:  3. In step (3) the user *sends* the mail from within mutt. Messages are
  110:     accumulated in the spool area.
  112:  4. In step (4) the user calls postfix's sendmail wrapper to transfer the
  113:     messages to the provider's SMTP server, that will deliver them to the final
  114:     destination (possibly through other mail servers). The provider's SMTP server
  115:     acts as a *relay* for our mail.
  117: The connection with the provider must be up only during steps (1) and (4); for
  118: the remaining steps it is not needed.
  120: ## postfix
  122: When an MTA must deliver a local message, it is delivered directly. If the
  123: message is intended for a different domain, the MTA must find out the address of
  124: the mail server for that domain. Postfix uses the DNS service (described in
  125: [[The Domain Name System|guide/dns]]) to find a mail exchanger handling mail for
  126: the given domain, and delivers the message to that mail server then.
  128: Postfix is controlled by a set of configuration files and databases, of which
  129: `/etc/postfix/` and `/etc/postfix/` are the most important.
  131: *Note*: Prior to version 1.5 of NetBSD, the mail configuration files were in
  132: `/etc` instead of `/etc/mail`. Since NetBSD 4.0, the `/etc/mail` directory is
  133: only used to store the local aliases and the corresponding
  134: [postmap(1)](
  135: database.
  137: The first problem to be solved is that the local network we are dealing with is
  138: an internal network, i.e. not directly accessible from the Internet. This means
  139: that the names used internally have no meaning on the Internet; in short,
  140: `` cannot be reached by an external host: no one will be able to
  141: reply to a mail sent with this return address (many mail systems will even
  142: reject the message as spam prevention as it comes from an unknown host). The
  143: true address, the one visible from everybody, is assigned by the provider and,
  144: therefore, it is necessary to convert the local address ``
  145: to the real address ``. Postfix, if correctly configured, will
  146: take care of this when it transfers the messages.
  148: You'll probably also want to configure postfix in order to send the e-mails to
  149: the provider's mail server, using it as a *relay*. In the configuration
  150: described in this chapter, postfix does not directly contact the recipient's
  151: mail server (as previously described) but relays all its mail to the provider's
  152: mail server.
  154: *Note*: The provider's mail server acts as a *relay*, which means that it
  155: delivers mail which is not destined to its own domain, to another mail server.
  156: It acts as an intermediary between two servers.
  158: Since the connection with the provider is not always active, it is not necessary
  159: to start postfix as a daemon in `/etc/rc.conf`: you can disable it with the line
  160: `postfix=NO`. As a consequence it will be necessary to launch postfix manually
  161: when you want to transfer mail to the provider. Local mail is delivered
  162: correctly even if postfix is not active as a daemon.
  164: Let's start configuring postfix.
  166: ### Configuration of generic mapping
  168: This type of configuration uses a new file `/etc/postfix/generic` which contains
  169: the hostname mapping used by postfix to rewrite the internal hostnames.
  171: The first step is therefore to write the mapping file:
  177: These entries will map the mail sent from the users given on the left side into
  178: the globally valid email addresses given on the right, making it appear as if
  179: the mail was really sent from that address.
  181: For the sake of efficiency, `generic` must be transformed into a binary file
  182: with the following command:
  184:     # postmap /etc/postfix/generic
  186: Now it's time to create the prototype configuration file which we'll use to
  187: create the postfix configuration file.
  189:     # vi /etc/postfix/
  191: For the sake of simplicity, we'll only show the variables you need change:
  193:     relayhost =
  194:     smtp_generic_maps = hash:/etc/postfix/generic
  196: This configuration tells postfix to rewrite the addresses of type
  197: `` using the real names found in the `/etc/postfix/generic` file.
  198: It also says that mail should be sent to the `` server. The
  199: meaning of the options is described in detail in
  200: [postconf(5)](
  202: The last step is to reload the configuration. You can do that easily with:
  204:     # /etc/rc.d/postfix reload
  205:     postfix/postfix-script: refreshing the Postfix mail system
  207: Now everything is ready to start sending mail.
  209: ### Testing the configuration
  211: Postfix is finally configured and ready to work, but before sending real mail it
  212: is better to do some simple tests. First let's try sending a local e-mail with
  213: the following command (postfix's sendmail wrapper):
  215:     $ sendmail carlo
  216:     Subject: test
  218:     Hello world
  219:     .
  221: Please follow exactly the example above: leave a blank line after Subject: and
  222: end the message with a line containing only one dot. Now you should be able to
  223: read the message with your mail client and verify that the From: field has been
  224: correctly rewritten.
  226:     From:
  228: ### Using an alternative MTA
  230: Starting from version 1.4 of NetBSD sendmail is not called directly:
  232:     $ ls -l /usr/sbin/sendmail
  233:     lrwxr-xr-x  1 root  wheel  21 Nov  1 01:14 /usr/sbin/sendmail@ -> /usr/sbin/mailwrapper
  235: The purpose of mailwrapper is to allow the usage of an alternative MTA instead
  236: of postfix (for example, sendmail). If you plan to use a different mailer I
  237: suggest that you read the
  238: [mailwrapper(8)](
  239: and the
  240: [mailer.conf(5)](
  241: manpages, which are very clear.
  243: ## fetchmail
  245: If someone sends me mail, it is received and stored by the provider, and not
  246: automatically transferred to the local hosts; therefore it is necessary to
  247: download it. Fetchmail is a very popular program that downloads mail from a
  248: remote mail server (using e.g. the Post Office Protocol, POP) and forwards it to
  249: the local system for delivery (usually using postfix's sendmail wrapper). It is
  250: powerful yet easy to use and configure: after installation, the file
  251: `~/.fetchmailrc` must be created and the program is ready to run
  252: (`~/.fetchmailrc` contains a password so appropriate permissions on the file are
  253: required).
  255: This is an example `.fetchmailrc`:
  257:     poll
  258:     protocol POP3
  259:     username alan there with password pZY9o is carlo here
  260:     flush
  261:     mda "/usr/sbin/sendmail -oem %T"
  263: The last line (`mda ...`) is used only if postfix is not active as daemon on the
  264: system. Please note that the POP-mail server indicated in this file
  265: ( is only used to retrieve mails, and that it is not necessary
  266: the same as the mail relay used by postfix to send out mails.
  268: After setting up the `.fetchmailrc` file, the following command can be used to
  269: download and deliver mail to the local system:
  271:     $ fetchmail
  273: The messages can now be read with mutt.
  275: ## Reading and writing mail with mutt
  277: Mutt is one of the most popular mail programs: it is *lightweight*, easy to use
  278: and has lots of features. The man page mutt is very bare bones; the real
  279: documentation is in `/usr/pkg/share/doc/mutt/`, in particular `manual.txt`.
  281: Mutt's configuration is defined by the `~/.muttrc` file. The easiest way to
  282: create it is to copy mutt's example muttrc file (usually
  283: `/usr/pkg/share/examples/mutt/sample.muttrc`) to the home directory and modify
  284: it. The following example shows how to achieve some results:
  286:  * Save a copy of sent mail.
  287:  * Define a directory and two files for incoming and outgoing mail saved by mutt
  288:    (in this example the directory is `~/Mail` and the files are `incoming` and
  289:    `outgoing`).
  290:  * Define some colors.
  291:  * Define an alias.
  293:     set copy=yes
  294:     set edit_headers
  295:     set folder="~/Mail"
  296:     unset force_name
  297:     set mbox="~/Mail/incoming"
  298:     set record="~/Mail/outgoing"
  299:     unset save_name
  301:     bind pager <up> previous-page
  302:     bind pager <down> next-page
  304:     color normal white black
  305:     color hdrdefault blue black
  306:     color indicator white blue
  307:     color markers red black
  308:     color quoted cyan black
  309:     color status white blue
  310:     color error red white
  311:     color underline yellow black
  313:     mono quoted standout
  314:     mono hdrdefault underline
  315:     mono indicator underline
  316:     mono status bold
  318:     alias pippo Pippo Verdi <>
  320: To start mutt:
  322:     $ mutt
  324: Please note that mutt supports color, but this depends on the terminal settings.
  325: Under X you can use "xterm-color", for example:
  327:     $ env TERM=xterm-color mutt
  329: ## Strategy for receiving mail
  331: This section describes a simple method for receiving and reading mail. The
  332: connection to the provider is activated only for the time required to download
  333: the messages; mail is then read offline.
  335:  1. Activate the connection to the provider.
  336:  2. Run `fetchmail`.
  337:  3. Deactivate the connection.
  338:  4. Read mail with mutt.
  340: ## Strategy for sending mail
  342: When mail has been written and *sent* with mutt, the messages must be
  343: transferred to the provider with postfix. Mail is sent from mutt with the `y`
  344: command, but this does not really send it; the messages are enqueued in the
  345: spool area; if postfix is not active as a daemon it is necessary to start it
  346: manually or the messages will remain on the hard disk. The necessary steps are:
  348:  1. Write mail with mutt, send it and exit mutt. You can check if and what
  349:     messages are in the postfix mail queue using the
  350:     [mailq(1)](
  351:     program.
  352:  2. Activate the connection with the provider.
  353:  3. If your provider requires you to do "SMTP-after-POP", i.e. it first wants to
  354:     make sure to know who you are before you are allowed to send mail (and no
  355:     spam), you need to run `fetchmail` again first.
  356:  4. Write the command `/usr/sbin/postfix flush` to transfer the queued
  357:     messages to the provider.
  358:  5. Deactivate the connection when the queue is empty.
  360: ## Advanced mail tools
  362: When you start using mail, you won't probably have very sophisticated
  363: requirements and the already described standard configuration will satisfy all
  364: your needs. But for many users the number of daily messages will increase with
  365: time and a more rational organization of the mail storage will become necessary,
  366: for example subdividing mail in different mail boxes organized by topic. If, for
  367: example, you subscribe to a mailing list, you will likely receive many
  368: messages every day and you will want to keep them separate from the rest of
  369: your mail. You will soon find that you are spending too much time every day
  370: repeating the same manual operations to organize your mail boxes.
  372: Why repeat the same operations manually when you can have a program perform them
  373: automatically for you? There are numerous tools that you can add to your mail
  374: system to increase its flexibility and automatically process your messages.
  375: Amongst the most known and used there are:
  377:  * *procmail*, an advanced mail delivery agent and general purpose mail filter
  378:    for local mail, which automatically processes incoming mail using user
  379:    defined rulesets. It integrates smoothly with sendmail/postfix.
  380:  * *spamassassin* or *spamprobe*, to help fight spam.
  381:  * *metamail*, a tool to process attachments.
  382:  * *formail*, a mail formatter.
  384: In the remaining part of this section a sample configuration for procmail will
  385: be presented for a very common case: delivering automatically to a user defined
  386: mailbox all the messages coming from a mailing list. The configuration of
  387: postfix will be modified in order to call procmail directly (procmail will be
  388: the *local mailer* used by sendmail). and a custom configuration file for
  389: procmail will be created.
  391: First, procmail must be installed using the package system (`mail/procmail`),
  392: `pkg_add` or `pkgin`.
  394: Next, the configuration of postfix must be changed, in order to use procmail as
  395: local mailer:
  397:     mailbox_command = /usr/pkg/bin/procmail
  399: The line defines the path of the procmail program (you can see where procmail is
  400: installed with the command `which procmail`).
  402: The last step is the creation of the procmail configuration file, containing the
  403: recipes for mail delivery.
  405: Let's say that, for example, you subscribed to a mailing list on roses whose
  406: address is `` and that every message from the list contains the
  407: following line in the header:
  409:     Delivered-To:
  411: Assuming you want to automatically sort all mails going over that list into the
  412: local mail folder `roses_list`, the procmail configuration file (`.procmailrc`)
  413: looks like this:
  415:     PATH=/bin:/usr/bin:/usr/pkg/bin
  416:     MAILDIR=$HOME/Mail
  417:     LOGFILE=$MAILDIR/from
  419:     :0
  420:     * ^Delivered-To:
  421:     roses_list
  423: The previous file contains only one rule, beginning with the line containing
  424: `:0`. The following line identifies all messages containing the string
  425: `Delivered-To:` and the last line says that the selected
  426: messages must go to the `roses_list` mailbox (which you should have created in
  427: $MAILDIR). The remaining messages will be delivered to the default mailbox. Note
  428: that $MAILDIR is the same directory that you have configured with mutt:
  430:     set folder="~/Mail"
  432: Of course the mailing list is only an example; procmail is a very versatile tool
  433: which can be used to filter mail based on many criteria. As usual, refer to the
  434: man pages for more details:
  435: [procmail(1)](,
  436: [procmailrc(5)](,
  437: and
  438: [procmailex(5)](
  439: (this last one contains many examples of configuration files).
  441: ## News with tin
  443: The word *news* indicates the set of messages posted to the USENET newsgroups, a
  444: service available on the Internet. Each newsgroup contains articles related to a
  445: specific topic. Reading a newsgroup is different than reading a mailing list:
  446: when you subscribe to a mailing list you receive the articles by mail and you
  447: read them with a standard mail program like mutt, which you use also to send
  448: replies. News, instead, are read directly from a news server with a dedicated
  449: program called *newsreader* like, for example, tin. With tin you can subscribe
  450: to the newsgroups that you're interested in and follow the *threads*. A thread
  451: is a sequence of articles which all derive from an article that we could call
  452: *original*. In short, a message is sent to the group, someone answers, other
  453: people answer to those who answered in the first place and so on, creating a
  454: tree like structure of messages and replies: without a newsreader it is
  455: impossible to understand the correct sequence of messages.
  457: After the installation of tin (from the package collection as usual) the only
  458: thing left to do is to write the name of the NNTP server in the file
  459: `/usr/pkg/etc/nntp/server`, which you may need to create first. For example:
  463: Once this has been done, the program can be started with the command `tin`. On
  464: the screen something similar to the following example will be displayed:
  466:     $ tin
  467:     Connecting to
  468: InterNetNews NNRP server INN 1.7.2 08-Dec-1997 ready (posting ok).
  469:     Reading groups from active file...
  470:     Checking for new groups...
  471:     Reading attributes file...
  472:     Reading newsgroups file...
  473:     Creating newsrc file...
  474:     Autosubscribing groups...
  475:     Reading newsrc file...
  477: Be patient when you connect for the first time, because tin downloads an immense
  478: list of newsgroups to which you can subscribe and this takes several minutes.
  479: When the download is finished, the program's main screen is displayed; usually
  480: no groups are displayed; to see the list of groups press `y`. To subscribe to a
  481: group, move on the group's name and press `y`.
  483: Once that you have subscribed to some newsgroups you can start tin more quickly
  484: with the command `tin -Q`. The search for new groups is disabled (`-q`), only
  485: active groups are searched (`-n`) and newsgroup description are not loaded
  486: (`-d`): it will not be possible to use the `y` (yank) command in tin. When tin
  487: is started with this option it can't tell if a newsgroup is moderated or not.
  489: Note that if you are connecting from an internal network (like in our example),
  490: when you send ("post") a message the address at the beginning of the message
  491: will be wrong (because it is the internal address). To solve the problem, use
  492: the option `mail_address` in the tin configuration file (`~/.tin/tinrc`) or set
  493: the `REPLYTO` environment variable.

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