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Chapter 16. Email 217

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new-mail.spool

Figure 16-10. Example with no conditions

The ﬁrst line starts the recipe by specifying that a local lockﬁle is to be created but does not specify

a name, leaving Procmail to use the destination ﬁlename and the LOCKEXT to name it. No condition

is speciﬁed, so every message will match this recipe and, therefore, will be placed in the single spool

ﬁle called new-mail.spool, located within the directory speciﬁed by the MAILDIR environment

variable. An MUA can then view the messages in this ﬁle.

This basic recipe could go at the end of all rc ﬁles to direct messages to a default location. A more

complicated example might grab messages from a particular email address and throw them away, as

can be seen in Figure 16-11.

/dev/null

Figure 16-11. Example of email sent to /dev/null

With this example, any messages sent by [email protected] are immediately moved to

/dev/null, deleting them.

Caution

Be very careful that a rule is working correctly before moving messages matching it to /dev/null,

which is a permanent deletion. If your recipe conditions inadvertently catch unintended messages,

you will not even know you are missing those messages unless the sender tells you.

A better solution is to point the recipe’s action to a special mailbox that you can check from time to

time in order to look for false positives, or messages that inadvertently matched the conditions. Once

you are satisﬁed that no messages are accidentally being matched, you can delete the mailbox and

direct the action to send the messages to /dev/null.

Procmail is primarily used as a ﬁlter for email, automatically placing it in the right place so that you

do not have to sort it manually. The recipe in Figure 16-12 grabs email sent from a particular mailing

list and puts in the correct folder for you.

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* ^(From|CC|To).*tux-lug

tuxlug

Figure 16-12. Example of list ﬁltering

Any messages sent from the [email protected] mailing list will be placed in the tuxlug mail-

box automatically for your MUA. Note that the condition in this example will match the message if it

has the mailing list’s email address on the From, CC, or To lines.

Procmail can also be used to block spam, although this is not a good long-term solution for junk mail.

Consider the following temporary spam ﬁltering solution in Figure 16-13, where multiple recipes are

set to use a common mailbox to store the junk.

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Red Hat LINUX 7.2 - OFFICIAL LINUX CUSTOMIZATION GUIDE Guida di Installazione Pagina 217