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Chapter 16. Email 209

16.4. Fetchmail

Fetchmail is a program that can retrieve email from remote servers for on-demand TCP/IP connec-

tions. Many users appreciate the ability to separate the process of downloading their messages located

on a remote server from the process of reading and organizing their email in an MUA. Designed with

the needs of dial-up users in mind, Fetchmail will connect and quickly download all of your email

messages to your mail spool ﬁle using any number of protocols, including the POP3 and IMAP. It can

even forward your email messages to an SMTP server, if necessary.

Before attempting to use Fetchmail, be sure that it is installed on your system. If it is not, you can

install it using the fetchmail RPM on the Red Hat Linux CD-ROMs.

Fetchmail is conﬁgured for each user through the use of a .fetchmailrc ﬁle in the user’s home

directory. A program bundled with Fetchmail, called fetchmailconf, is very helpful for conﬁguring

a basic .fetchmailrc ﬁle that you can customize at will.

Using preferences in the .fetchmailrc ﬁle, Fetchmail will check for email on a remote server and

pull it off, attempting to deliver it to port 25 on the local machine, using the local MTA to place the

email in the correct user’s spool ﬁle. If Procmail is available, it can then be utilized to ﬁlter the email

and place it in a mailbox so that it can be read by an MUA.

16.4.1. Fetchmail Conﬁguration Options

Although it is possible to pass all options on the command line necessary to check for email on a

remote server when executing Fetchmail, using a .fetchmailrc ﬁle is much easier. All of your

conﬁguration options go in the .fetchmailrc ﬁle, but you can override them at the time Fetchmail

is run by specifying that option on the command line.

A user’s .fetchmailrc ﬁle is divided into three particular types of conﬁguration options:

• global options — Gives Fetchmail instructions that control the operation of the program or provide

settings for every connection that checks for email.

• server options — Speciﬁes necessary information about the server being polled, such as the host-

name, as well as preferences you would like to see enforced with a particular email server, such as

the port to check or number of seconds to wait before timing out. These options affect every user

option utilized with that server.

• user options — Contains information, such as username and password, necessary to authenticate

and check for email using a particular email server.

Global options go at the top of the .fetchmailrc ﬁle, followed by one or more server options,

each of which designate a different email server that Fetchmail should check. User options follow

server options for each user account you would like to check on that email server. Like server options,

multiple user options may be speciﬁed for use with a particular server, such as when you would like

to check multiple email accounts on the same server.

Server options are called into service in the .fetchmailrc ﬁle by the use of a special option verb,

poll or skip, that precedes any of the server information. The poll action tells Fetchmail to use

this server option when it is run, which actually checks it for email using the various user options.

Any server options after a skip action, however, are not checked unless you specify this server’s

hostname when Fetchmail is invoked. The skip option allows you to set up test conﬁgurations in

.fetchmailrc and only check using that server when speciﬁcally desired, without affecting any

currently working conﬁgurations.

A sample .fetchmailrc ﬁle looks like this:

1 2 ... 204 205 206 207 208 209 210 211 212 213 214 ... 281 282

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Red Hat LINUX 7.2 - OFFICIAL LINUX CUSTOMIZATION GUIDE Guida di Installazione Pagina 209

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