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       courieruucp - Sample Courier mail filter




       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

   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 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

       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:

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

           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.

           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".

           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:

           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.

           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.

           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

           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.


       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, and your UUCP node is example, then
       <> gets rewritten as example!user.

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

       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!someone, and translate it back as


       Courier does not support defining multiple UUCP node names in


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


        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