NAME

       courieruucp - Sample Courier mail filter

SYNOPSIS

       makeuucpneighbors

DESCRIPTION

       The Courier mail server is capable of sending and receiving mail via UUCP. Courier does
       not implement UUCP directly, but instead uses third-party UUCP software, which you must
       install separately. Courier´s UUCP support is provided automatically by the courieruucp
       module, which is compiled and installed by default.

       Courier sends mail via UUCP by issuing a request via uux to execute the rmail command on
       the remote UUCP node. Courier passes the message envelope sender to rmail via the -f flag,
       and lists the message envelope recipients as the remaining arguments. Message envelope
       addresses and E-mail addresses in the headers of the message will be appropriately
       rewritten.

       Courier will only send mail via UUCP if it knows about the recipient´s UUCP node. The
       configuration file /etc/courier/uucpneighbors is a plain text configuration file. The
       makeuucpneighbors script compiles this configuration file into a binary database that is
       read by Courier. Changes to /etc/courier/uucpneighbors do not take effect until
       makeuucpneighbors is executed, and Courier is restarted.

       /etc/courier/uucpneighbors may also be a subdirectory instead of a plain text file, in
       which case the contents of all text files in this subdirectory is automatically
       concatenated by the makeuucpneighbors script.

   Contents of /etc/courier/uucpme
       This configuration file must be initialized to contain the UUCP node name that this
       machine is known to its neighbors. If /etc/courier/uucpme does not exist, Courier uses the
       first node name of the hostname specified by the /etc/courier/me configuration file.

   Contents of /etc/courier/uucpneighbors
       Note that in addition to creating this configuration file you must also configure your
       UUCP software to appropriately route UUCP mail to the specified nodes, which is a
       completely separate task. Blank lines in this file are ignored. Lines that start with the
       # character are comments, and are also ignored. The remaining lines are in the following
       format:

           node<TAB>flags

       node is a UUCP node, such as "apple" or "food!fruits!apple". <TAB> is a single tab
       character, and flags is zero or more of single character flags described below. The tab
       character can be ommited if there are no flags.

       If there is an entry for node in /etc/courier/uucpneighbors then Courier will accept mail
       for any address of the form "node!user", but not "node!nodule!user". In order to accept
       mail for "node!nodule!user" you must enter both "node" and "node!nodule", unless you use
       the F or the G flag.

       The flags are as follows:

       F
           Unrestricted forwarding. This flag will accept any UUCP path that starts with the
           specified node. Example:

               food<TAB>F
           This will accept "food!fruits!apple", "food!fruits!banana", "food!drinks!orangejuice",
           and so on. You may simply list all your immediate UUCP neighbors using the F flag, and
           accept mail to any address that´s reachable via any neighbor.

       G
           This is a gateway. This flag is identical to the F flag, except that rmail is executed
           on the specified node. Normally, Courier will issue a uux request to run rmail on the
           last node, for example "uux food!fruits!rmail apple". Using G instead of F will run
           rmail on the listed node, for example "uux food!rmail fruits!apple".

       R
           This is a relay. This flag is used where neither F or G flags are appropriate, but you
           want to run rmail on this node. For example:

               food!fruits
               food<TAB>R
           In this example mail to "food!fruits!apple" is sent by executing "uux food!rmail
           fruits!apple". If the R flag is not specified, then Courier will request "uux
           food!fruits!rmail apple".

   Contents of /etc/courier/module.uucp
       This is the standard Courier module configuration file.

       MAXDELS
           Maximum simultaneous UUCP deliveries. This setting is a bit misleading. From Courier´s
           viewpoint, a delivery consists only of running uux to queue up the message via UUCP.
           Once uux returns, the message is delivered, as far as Courier is concerned. UUCP is
           responsible for getting the message the rest of the way. Therefore, UUCP deliveries
           tend to be fairly quick, and it is not necessary to configure a large number of
           concurrent courieruucp processes, since each one will terminate quickly. Once uux
           terminates, the UUCP software is responsible for queueing and sending the message.

       MAXHOST
           Maximum simultaneous UUCP deliveries to the same UUCP node. Since UUCP deliveries tend
           to be fairly quick, it is not usually necessary to use MAXHOST to limit concurrent
           deliveries to the same UUCP node, so MAXHOST should generally be set to the same value
           as MAXDELS.

       MAXRCPT
           Maximum recipients per message. When the same message is sent to multiple recipients
           on the same UUCP node, Courier is capable of asking to run rmail only one, and listing
           all the recipients together.  MAXRCPT specifies the upper limit on the number of
           recipients that are batched together. You want to set a limit based on any limitations
           on the length of command lines that´s imposed by the operating system. Sending the
           same message to different UUCP nodes is always handled as separate deliveries.

HEADER AND ADDRESS REWRITING

       Courier is certainly capable of relaying mail between the Internet - via ESMTP - and
       UUCP-land, rewriting headers and addresses appropriately. The address rewriting rules are
       fixed, but they are expected to work in nearly every case. If you find yourself in some
       oddball situation, you´ll just have to invest the time to add custom header rewriting
       code.

       If you are example.com, and your UUCP node is example, then <user@example.com> gets
       rewritten as example!user.

       Internet mail may be sent via ESMTP to your UUCP neighbor apple!john by sending it to
       <apple!john@example.com>. When that´s forwarded via UUCP the return address of
       <someone@domain.com> will be rewritten as example!domain.com!someone.

       apple!john will get the mail with this return address, which should be repliable back to
       the sender. Courier´s UUCP module will receive the UUCP address domain.com!someone, and
       translate it back as <someone@domain.com>.

BUGS

       Courier does not support defining multiple UUCP node names in /etc/courier/uucpme.

SEE ALSO

       esmtpd(8)[1], couriertcpd(8)[2], courier(8)[3].

AUTHOR

       Sam Varshavchik
           Author

NOTES

        1. esmtpd(8)
           [set $man.base.url.for.relative.links]/esmtpd.html

        2. couriertcpd(8)
           [set $man.base.url.for.relative.links]/couriertcpd.html

        3. courier(8)
           [set $man.base.url.for.relative.links]/courier.html