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1.1     ! root        1: .if n .pH aguide2.mail %W%
        !             2: .Bk "System Administrator's Guide"
        !             3: .CH "Mail Subsystem Administration" F
        !             4: .H 1 "Administering the Mail Subsystem"
        !             5: .IX istart \f4mail\f1, administration
        !             6: The purpose of this appendix is to aid the System Administrator in taking
        !             7: advantage of various options within the mail subsystem.
        !             8: By default, the mail subsystem provides electronic communications between
        !             9: users on the same machine, or between machines connected together on a UUCP
        !            10: network, and
        !            11: supports two addressing schemes, known as ``bang'' style and ``domain''
        !            12: style.
        !            13: .IX \f4mail\f1, bang addressing
        !            14: .IX \f4mail\f1, domain addressing
        !            15: The System Administrator does not need to do anything for mail to work in
        !            16: the default manner.
        !            17: .P
        !            18: .IX \f4mail\f1, smart host
        !            19: This appendix will provide information on
        !            20: setting up a smarter host,
        !            21: establishing a domain name,
        !            22: administering a set of sites so that they all send mail with the same machine
        !            23: name,
        !            24: .IX \f4mail\f1, machine cluster
        !            25: .IX \f4mail\f1, gateway machine
        !            26: setting up the mail directory to be shared across a networked file
        !            27: system, such as RFS and NFS,
        !            28: .IX \f4mail\f1, LAN
        !            29: .IX \f4mail\f1, RFS
        !            30: .IX \f4mail\f1, NFS
        !            31: filling in alias information,
        !            32: .IX \f4mail\f1, alias lists
        !            33: and
        !            34: setting up a connection to another site that uses the
        !            35: .IX \f4mail\f1, SMTP (Simple Mail Transfer Protocol)
        !            36: .IX SMTP (see \f4mail\f1)
        !            37: .IX Simple Mail Transfer Protocol (see \f4mail\f1)
        !            38: Simple Mail Transfer Protocol (SMTP).
        !            39: .H 2 "Mail Administration Files"
        !            40: .IX files, mail
        !            41: .IX \f4mail\f1, files
        !            42: .IX \f4/usr/lib/mail\f1 files
        !            43: .IX \f4/etc/mail\f1 files
        !            44: .IX \f4mail\f1, \f4/etc/mail\f1 files
        !            45: There are four files that are important to mail administration.
        !            46: The surrogate file, \f4/etc/mail/mailsurr\f1,
        !            47: .IX \f4mailsurr\f1 mail file
        !            48: is described on the \f4mailsurr\f1(4) manual page.
        !            49: It describes how to rewrite addresses and how to deliver messages through
        !            50: the networks.
        !            51: The configuration file, \f4/etc/mail/mailcnfg\f1,
        !            52: .IX \f4mailcnfg\f1 mail file
        !            53: is described on \f4mailcnfg\f1(4).
        !            54: It permits various per-site options to be established.
        !            55: For more information on the \f4mailsurr\f1 and \f4mailcnfg\f1 manual pages,
        !            56: see the \f2System Administrator's Reference Manual\f1.
        !            57: The master alias path file, \f4/etc/mail/namefiles\f1, points
        !            58: .IX \f4namefiles\f1 mail file
        !            59: to one alias file, \f4/etc/mail/names\f1.
        !            60: Both are described on
        !            61: \f4mailalias\f1(1).
        !            62: .IX \f4names\f1 mail file
        !            63: These two files are used to define name mappings and address lists.
        !            64: For more information on the \f4mailalias\f1 manual page, see
        !            65: the \f2User's Reference Manual\f1.
        !            66: .H 3 "Mail Addressing Styles"
        !            67: .IX \f4mail\f1, address style translation
        !            68: .IX address style translation (see \f4mail\f1)
        !            69: The default surrogate file contains entries to translate between domain
        !            70: style addresses and bang style addresses.
        !            71: Bang style addressing is
        !            72: characterized by exclamation points (a.k.a. bangs) within the
        !            73: address and looks like \f2host\f4!\f2user\f1
        !            74: or \f2host1\f4!\f2host2\f4!\f2user\f1.
        !            75: Domain style addressing is characterized by the commercial
        !            76: at sign (\f4@\f1) and looks like \f2user\f4@\f2host\f4.\f2domain\f1
        !            77: or \f2user\f4@\f2host\f1.
        !            78: .H 2 "Establishing a Smarter Host"
        !            79: Although it is possible to maintain the data files for the UUCP
        !            80: network so that the system knows about hundreds or thousands of other
        !            81: systems that can be contacted, it is impractical to do so.
        !            82: It is often much easier to set up what is known as a ``smarter host,'' that is,
        !            83: another UNIX system to which remote mail will be shipped if the
        !            84: local machine doesn't know about the system to which the mail is being sent.
        !            85: For example, assume you need to send a mail message to \f4hosta!tony\f1,
        !            86: but your local machine does not know about \f4hosta\f1.
        !            87: The mail message can be automatically routed to the machine
        !            88: \f4worldly\f1, which has a more extensive list of UUCP connections.
        !            89: .P
        !            90: This is done in two steps:
        !            91: .AL
        !            92: .LI
        !            93: Add a line to mailcnfg that says
        !            94: .DS I UI
        !            95: SMARTERHOST=\f2smhost\fP
        !            96: .DE
        !            97: where \f2smhost\f1 is replaced with the name of the smarter system (\f4worldly).
        !            98: .LI
        !            99: Remove the \f4#\f1 character from the line within
        !           100: \f4mailsurr\f1 that looks like this:
        !           101: .DS I UI
        !           102: #'.+'  '.*[!@].*'      'Translate R=%X!%n'
        !           103: .DE
        !           104: .LE
        !           105: .H 2 "Establishing Domain Addresses"
        !           106: .IX istart \f4mail\f1, domain addressing
        !           107: As distributed, mail knows about two forms of domain style addresses:
        !           108: .DS I
        !           109: \f2user\f4@\f2host\f1
        !           110: .DE
        !           111: and
        !           112: .DS I
        !           113: \f2user\f4@\f2host\f4.UUCP\f1
        !           114: .DE
        !           115: It does not know about
        !           116: .DS I
        !           117: \f2user\f4@\f2host\f4.\f2domain\f1
        !           118: .DE
        !           119: A domain name is an internationally recognized and registered name for a
        !           120: set of machines.
        !           121: Commercial entities may be registered under domain names similar to
        !           122: \&\f4.\f2company-name\f4.COM\f1 and educational entities may be registered
        !           123: under domain names similar to \(CW.\f2school\f4.EDU\f1.
        !           124: (Note that \f4.UUCP\f1 is not a true domain name.
        !           125: The high-level domain names of \f4.COM\f1 and \f4.EDU\f1 are assigned
        !           126: by a central authority.)
        !           127: A system will generally know how to establish direct connections to
        !           128: other machines within the local domain, 
        !           129: but will want to make use of a smarter host to take care of other domains.
        !           130: .P
        !           131: To establish the local domain name, complete this step:
        !           132: .AL
        !           133: .LI
        !           134: Type the command
        !           135: .DS I UI
        !           136: /usr/sbin/domainname \f2domain\fP
        !           137: .DE
        !           138: where \f2domain\f1 is replaced with the domain name, such as
        !           139: \&\f4.\f2company-name\f4.COM\f1 or whatever is appropriate, and contains
        !           140: the leading period.
        !           141: (Any periods present within the domain name will be converted to 
        !           142: \f4\e.\f1 before being passed to the regular expressions in the surrogate
        !           143: file.)
        !           144: .LE
        !           145: The domain name will also be used by the SMTP router when rewriting
        !           146: header files into RFC822 format (see ``Administering SMTP'' below).
        !           147: .IX iend \f4mail\f1, domain addressing
        !           148: .H 2 "Establishing a Mail Cluster or Gateway"
        !           149: .IX istart \f4mail\f1, machine cluster
        !           150: .IX istart \f4mail\f1, gateway machine
        !           151: With the arrival of inexpensive personal computers, it is often desirable
        !           152: to assign a single name to a set (or a cluster) of machines by which all the
        !           153: machines in the cluster will be known to external machines, for purposes of
        !           154: mail.
        !           155: For example, a cluster of machines known internally under names such as
        !           156: \f4Xsysa\f1, \f4Xsysb\f1 and \f4Xsysc\f1, could be assigned the cluster name
        !           157: of \f4Xsys\f1.
        !           158: Mail sent from any of these machines would be shown as being from \f4Xsys\f1;
        !           159: that is, the internal names would not be known outside the cluster.
        !           160: .P
        !           161: To establish a cluster name, add a line to the \f4mailcnfg\f1 that says:
        !           162: .DS I UI
        !           163: CLUSTER=\f2extname\fP
        !           164: .DE
        !           165: where \f2extname\f1 is the name by which the machine is known
        !           166: externally (\f4Xsys\f1).
        !           167: .IX iend \f4mail\f1, machine cluster
        !           168: .IX iend \f4mail\f1, gateway machine
        !           169: .H 2 "Establishing Mail Service on a Networked File System (RFS or NFS)"
        !           170: .IX istart \f4mail\f1, LAN
        !           171: .IX istart \f4mail\f1, RFS
        !           172: .IX istart \f4mail\f1, NFS
        !           173: With the arrival of inexpensive Local Area Networking (LAN) and networked file
        !           174: systems such as RFS and NFS, clusters of machines 
        !           175: that share many file systems can be set up.
        !           176: It is also possible to share \f4/var/mail\f1 across the machines.
        !           177: .IX \f4/var/mail\f1
        !           178: .IX files, mail
        !           179: .IX \f4mail\f1, files
        !           180: In this case, you can arrange to have all user's mail boxes created on only
        !           181: one machine, but accessible from all machines.
        !           182: .P
        !           183: As an example, assume that you want the machines \f4Xsysa\f1, \f4Xsysb\f1 and
        !           184: \f4Xsysc\f1 to share the mail directory under \f4Xsysa\f1.
        !           185: In addition, the entire file system for each system is mounted under the names
        !           186: \f4/Xsysa\f1, \f4/Xsysb\f1 and \f4/Xsysc\f1.
        !           187: All users have home directories under file systems named \f4/homea\f1,
        !           188: \f4/homeb\f1 and \f4/\f1homec, which are mounted on
        !           189: the corresponding machines.
        !           190: .P
        !           191: To establish a shared \f4/var/mail\f1 file system, complete the following
        !           192: steps:
        !           193: .AL
        !           194: .LI
        !           195: Make certain that \f4/var/mail\f1 from \f4Xsysa\f1 is advertised.
        !           196: .LI
        !           197: Remove the directory \f4/var/mail/:saved\f1 from the systems that
        !           198: will not have a local \f4/var/mail\f1 (\f4Xsysb\f1 and \f4Xsysc\f1).
        !           199: .LI
        !           200: Add a line to \f4mailcnfg\f1 that says
        !           201: .DS I UI
        !           202: FAILSAFE=Xsysa
        !           203: .DE
        !           204: With this specified, \f4mail\f1 will look for the presence of
        !           205: \f4/var/mail/:saved\f1.
        !           206: If the directory is not there (indicating that the network connection to
        !           207: \f4Xsysa\f1 has been lost), \f4mail\f1 will requeue the file to be delivered to
        !           208: \f4Xsysa\f1 via other means (such as UUCP or SMTP).
        !           209: .LI
        !           210: Move any mailboxes from \f4/var/mail\f1 on \f4Xsysb\f1 and
        !           211: \f4Xsysc\f1 to \f4Xsysa\f1 (otherwise the files will be inaccessible).
        !           212: .LI
        !           213: Mount \f4/var/mail\f1 from \f4Xsysa\f1.
        !           214: .LI
        !           215: In order for the \f4notify\f1 program to identify where the
        !           216: user is logged in (so that it can notify the user when new mail arrives),
        !           217: create a file on all machines named \f4/etc/mail/notify.sys\f1
        !           218: with contents similar to the following:
        !           219: .SS
        !           220: Xsysa  /Xsysa
        !           221: Xsysb  /Xsysb
        !           222: Xsysc  /Xsysc
        !           223: .SE
        !           224: The first column lists the name of the system and the second gives a pathname
        !           225: of the \f4root\f1 filesystem for each machine.
        !           226: .LI
        !           227: In order for the \f4notify\f1 program to handle a network failure,
        !           228: create a file on all machines named \f4/etc/mail/notify.fsys\f1
        !           229: with contents similar to the following:
        !           230: .SS
        !           231: /homea Xsysa
        !           232: /homeb Xsysb
        !           233: /homec Xsysc
        !           234: .SE
        !           235: The first column lists a file system name and the second column contains the
        !           236: system (machine name) on which that file system is normally mounted.
        !           237: If \f4notify\f1 cannot open the mail file for writing, it will look up the
        !           238: file system in this list and requeue the file to be delivered to the
        !           239: corresponding system via other means (such as UUCP or SMTP).
        !           240: .LE
        !           241: .IX iend \f4mail\f1, LAN
        !           242: .IX iend \f4mail\f1, RFS
        !           243: .IX iend \f4mail\f1, NFS
        !           244: .H 2 "Administering \f4alias\fP Lists"
        !           245: .IX istart \f4mail\f1, alias lists
        !           246: .IX istart alias lists, \f4mail\f1
        !           247: Before delivering a local mail message, \f4mail\f1 will look up the user name to
        !           248: see if it has been aliased to another name or list of names.
        !           249: The master alias path file \f4/etc/mail/namefiles\f1 contains a list of
        !           250: files that \f4mail\f1 will search for aliases.
        !           251: As distributed, this list contains only one file,
        !           252: \f4/etc/mail/names\f1, to be searched for aliases.
        !           253: If the named alias is found at the beginning of a line within an alias file,
        !           254: the rest of that line will be used as the alias.
        !           255: This may contain a single name, or a list of names separated by whitespace.
        !           256: For example, if you want to set up a group mailing list (e.g., \f4andy.group\f1)
        !           257: that will be expanded, add a line similar to the following to the alias file:
        !           258: .DS I UI
        !           259: andy.group tony paul john ned gary hailey mike
        !           260: .DE
        !           261: Recursive references are permitted, as in this reference to
        !           262: \f4andy.group\f1 within another alias:
        !           263: .DS I UI
        !           264: armida.dept andy.group danielle.group bob.group \e
        !           265:        lee.group pier.group
        !           266: .DE
        !           267: Several alias files can be listed in \f4namefiles\f1, which may be kept
        !           268: anywhere on the machine.
        !           269: This permits different alias files to be owned by different administrators.
        !           270: .IX iend \f4mail\f1, alias lists
        !           271: .IX iend alias lists, \f4mail\f1
        !           272: .H 2 "Other Tricks of the \f4surrogate\fP File Trade"
        !           273: .H 3 "Logging Mail"
        !           274: .IX \f4mail\f1, logging
        !           275: .IX logging mail
        !           276: Occasionally it may be necessary to keep a log of traffic going through the
        !           277: system.
        !           278: For example, if you were to write a program \f4/usr/lib/mail/surrcmd/logmail\fP
        !           279: that takes three arguments (a log file name, the sender and recipient), it
        !           280: could log all external mail flowing through the system by using this
        !           281: surrogate entry:
        !           282: .SS
        !           283: \&'.+!.+' '.*' '> /usr/lib/mail/surrcmd/logmail /var/adm/mailtransport %R %n'
        !           284: .SE
        !           285: Another example would be to log traffic to or from
        !           286: a particular system (here to \f5xyz\f1 and from \f5abc\f1):
        !           287: .SS
        !           288: \&'.*' 'xyz!.+' '> /usr/lib/mail/surrcmd/logmail /var/adm/mailto-xyz %R %n'
        !           289: \&'abc!.+' '.*' '> /usr/lib/mail/surrcmd/logmail /var/adm/mailfrom-abc %R %n'
        !           290: .SE
        !           291: .H 3 "Path Translation"
        !           292: .IX PATH Translation
        !           293: .IX translate, PATH
        !           294: Many systems have a path translation program available that will give the
        !           295: shortest route to a given system, based on various criteria or a database.
        !           296: An example of this is the public domain smail program.
        !           297: As an alternative to using a smarter host, the autorouter can be invoked as
        !           298: a final step in the mailsurr file:
        !           299: .SS
        !           300: \&'.+' '.*[!@].*'              'Translate R=|smail -A %n'
        !           301: .SE
        !           302: .H 3 "Controlling Mail Resource Access"
        !           303: .IX Deny, mail access
        !           304: .IX \f4mail\f1, controlling access
        !           305: It is often necessary to control access to commercial services, such as AT&T
        !           306: Mail.
        !           307: One method of doing this is to prevent any non-local users from sending mail
        !           308: to the commercial site using the Accept and Deny commands:
        !           309: .SS
        !           310: \&'[^!]+' 'attmail!.+' 'Accept'
        !           311: \&'.+'    'attmail!.+' 'Deny'
        !           312: .SE
        !           313: Another method is to use an external program to check the sender's path to
        !           314: see if it is a valid user of the service.
        !           315: For example, this shell script returns 0 if the sender is a valid system,
        !           316: and 1 otherwise:
        !           317: .SS
        !           318: case "$1" in
        !           319:     abc | def | ghi ) exit 0 ;;
        !           320:     * ) echo "$1 is not permitted to send mail to external service"
        !           321:        exit 1 ;;
        !           322: esac
        !           323: .SE
        !           324: If the script were installed as /usr/lib/mail/surrcmd/chksender,
        !           325: it would be invoked as a delivery agent which will either continue or fail:
        !           326: .SS
        !           327: # check senders more than one hop away
        !           328: \&'.+!(.+)![^!]+' 'attmail!.+' '< C=0;F=*; /usr/lib/mail/surrcmd/chksender \e\e1'
        !           329: # check senders one hop away
        !           330: \&'(.+)![^!]+'    'attmail!.+' '< C=0;F=*; /usr/lib/mail/surrcmd/chksender \e\e1'
        !           331: .SE
        !           332: .H 2 "Administering SMTP"
        !           333: .IX istart \f4mail\f1, SMTP (Simple Mail Transfer Protocol)
        !           334: .IX SMTP (see \f4mail\f1)
        !           335: .IX Simple Mail Transfer Protocol (see \f4mail\f1)
        !           336: .IX TCP/IP
        !           337: The Simple Mail Transfer Protocol
        !           338: (SMTP) mail subsystem is delivered as a group of programs that
        !           339: allow UNIX System mail to send and receive mail using the SMTP protocol.
        !           340: This protocol is typically used over TCP/IP networks.
        !           341: However, as delivered, the SMTP processes can connect over any
        !           342: TLI-based, connection-oriented, transport that has been administered
        !           343: to have an SMTP service.
        !           344: .P
        !           345: To establish SMTP service requires these steps:
        !           346: .AL
        !           347: .LI
        !           348: By default, SMTP is installed in the mail surrogate file,
        !           349: but it is turned off (commented out).
        !           350: It may be turned on by uncommenting the line that says:
        !           351: .SS
        !           352: #'.+' '([^!@]+)!(.+)' '< /usr/lib/mail/surrcmd/smtpqer %R \e\e1 \e\e2'
        !           353: .SE
        !           354: To uncomment this line, edit the \f4mailsurr\f1 file to
        !           355: remove the \f4#\f1 from the start of each line.
        !           356: .P
        !           357: Mail is addressed using the standard UNIX system mail
        !           358: formats of \f2host\f4!\f2user\f1 or \f2user\f4@\f2host\f1.
        !           359: If \f2host\f1 is known to support SMTP mail delivery, the mail
        !           360: will be queued for delivery using SMTP.
        !           361: If not, \f4smtpqer\f1 will not accept the message, and delivery will be
        !           362: done by subsequent surrogates in the \f4mailsurr\f1 file.
        !           363: .P
        !           364: .IX files, SMTP (see \f4mail\f1)
        !           365: All messages that are spooled for SMTP delivery are stored in the directory
        !           366: \f4/var/spool/smtpq/\f2host\f1, where \f2host\f1 is the name of the machine
        !           367: to which mail is being sent.
        !           368: .LI
        !           369: The list of machines that will accept SMTP mail is specified by the
        !           370: \f4netdird\f1 service.
        !           371: See \f4netdird\f1(1M) in the \f2System Administrator's Reference Manual\f1
        !           372: to see how to add services to this database.
        !           373: By default, the SMTP daemon \f4smtpd\f1 will always start when
        !           374: your system is booted.
        !           375: If \f4smtpd\f1 finds that there are no networks installed for which the
        !           376: SMTP service is defined, it will exit.
        !           377: .P
        !           378: When the daemon \f4smtpd\f1 receives a piece of mail, it does three things:
        !           379: 1) it inserts a valid UNIX System mail ``\f4From \f1''
        !           380: header line;
        !           381: 2) it converts the recipient address to \f2host\f4!\f2user\f1 form; and,
        !           382: 3) hands the message to \f4rmail\f1 for delivery.
        !           383: .LI
        !           384: The following entry must be uncommented from \f4root\f1's \f4crontab\f1 file
        !           385: [see \f4crontab\f1(1) for an explanation of this file]:
        !           386: .SS
        !           387: 25 * * * * /usr/lib/mail/surrcmd/smtpsched
        !           388: 55 1 * * * /usr/lib/mail/surrcmd/smtpsched -c -w 1 -r 7
        !           389: .SE
        !           390: To do this, execute the following commands as root:
        !           391: .SS
        !           392: # crontab -l > /tmp/cron.temp
        !           393: # ed /tmp/cron.temp
        !           394: g!/smtpsched!s/^#//
        !           395: w
        !           396: q
        !           397: # crontab /tmp/cron.temp
        !           398: # rm /tmp/cron.temp
        !           399: #
        !           400: .SE
        !           401: .P
        !           402: By default, mail that cannot be delivered immediately (as
        !           403: it is sent), is queued and retried at one hour intervals by \f4smtpsched\f1.
        !           404: You can change the interval by modifying the
        !           405: entry for \f4smtpsched\f1 in \f4root\f1's \f4cron\f1 file.
        !           406: .IX \f4smtpsched\f1(1M)
        !           407: .LE
        !           408: .P
        !           409: .IX logs, SMTP (see \f4mail\f1)
        !           410: SMTP logs all SMTP activity, including
        !           411: incoming mail messages, in the log file \f4/var/spool/smtpq/LOG\f1.
        !           412: .IX \f4/var/spool/smtpq/LOG\f1
        !           413: It is backed up once per day by \f4smtpsched\f1; previous days' log files are
        !           414: located in \f4/var/spool/smtpq/LOG.\f2n\f1, where \f2n\f1 is the day
        !           415: of the week (from 0 to 6).
        !           416: The \f4smtpsched\f1 program will also return undeliverable mail messages.
        !           417: For more information on \f4smtpsched\f1(1M)
        !           418: see the \f2System Administrator's Reference Manual\f1.
        !           419: .H 3 "Setting Up SMTP to Listen Over Multiple Networks"
        !           420: \f4smtpd\f1 will listen to any connection-oriented TLI network
        !           421: that provides the SMTP service.
        !           422: TLI networks are specified in \f4/etc/netconfig\f1.
        !           423: For each network that is
        !           424: connection-oriented, \f4smtpd\f1 will use \f4netdir_getbyname\f1(3) to
        !           425: determine if the SMTP service exists for that network.
        !           426: If the service does exist, a port is opened at the address returned by this
        !           427: function.
        !           428: To make the listener listen to a new network,
        !           429: first administer the \f4netdir\f1 databases, and then restart the listener.
        !           430: .IX iend \f4mail\f1, SMTP (Simple Mail Transfer Protocol)
        !           431: .IX iend \f4mail\f1, administration

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