[root@linux ~]# yum -y install dovecot 
Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
core                                                                 [1/3]
updates                                                              [2/3]
extras                                                               [3/3]
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Downloading header for dovecot to pack into transaction set.
dovecot-1.0-0.beta8.2.fc5 100% |=========================|  25 kB    00:00
---> Package dovecot.i386 0:1.0-0.beta8.2.fc5 set to be updated
--> Running transaction check
--> Processing Dependency: libmysqlclient.so.15 for package: dovecot
--> Processing Dependency: libmysqlclient.so.15(libmysqlclient_15) for package: dovecot
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. Please wait.
---> Downloading header for mysql to pack into transaction set.
mysql-5.0.22-1.FC5.1.i386 100% |=========================|  37 kB    00:00
---> Package mysql.i386 0:5.0.22-1.FC5.1 set to be updated
--> Running transaction check
--> Processing Dependency: perl(DBI) for package: mysql
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. Please wait.
---> Downloading header for perl-DBI to pack into transaction set.
perl-DBI-1.50-2.2.i386.rp 100% |=========================|  17 kB    00:00
---> Package perl-DBI.i386 0:1.50-2.2 set to be updated
--> Running transaction check

Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size
=============================================================================
Installing:
 dovecot                 i386       1.0-0.beta8.2.fc5  updates           1.2 M
Installing for dependencies:
 mysql                   i386       5.0.22-1.FC5.1   updates           3.0 M
 perl-DBI                i386       1.50-2.2         core              581 k

Transaction Summary
=============================================================================
Install      3 Package(s)
Update       0 Package(s)
Remove       0 Package(s)
Total download size: 4.7 M
Downloading Packages:
(1/3): dovecot-1.0-0.beta 100% |=========================| 1.2 MB    00:04
(2/3): perl-DBI-1.50-2.2. 100% |=========================| 581 kB    00:03
(3/3): mysql-5.0.22-1.FC5 100% |=========================| 3.0 MB    00:12
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing: perl-DBI                     ######################### [1/3]
  Installing: mysql                        ######################### [2/3]
  Installing: dovecot                      ######################### [3/3]

Installed: dovecot.i386 0:1.0-0.beta8.2.fc5
Dependency Installed: mysql.i386 0:5.0.22-1.FC5.1 perl-DBI.i386 0:1.50-2.2
Complete!

[root@linux ~]# vi /etc/dovecot.conf 

  :
  :
# Protocols we want to be serving:
#  imap imaps pop3 pop3s
# プロトコルを指定
protocols = imap imaps pop3 pop3s
  :
  :
# Default MAIL environment to use when it's not set. By leaving this empty
# dovecot tries to do some automatic detection as described in
# doc/mail-storages.txt. There's a few special variables you can use:
#
#   %u - username
#   %n - user part in user@domain, same as %u if there's no domain
#   %d - domain part in user@domain, empty if user there's no domain
#   %h - home directory
#
# You can also limit a width of string by giving the number of max. characters
# after the '%' character. For example %1u gives the first character of
# username. Some examples:
#
#   maildir:/var/mail/%1u/%u/Maildir
#   mbox:~/mail/:INBOX=/var/mail/%u
#   mbox:/var/mail/%d/%n/:INDEX=/var/indexes/%d/%n
#
# メールボックス(Maildir)を各ユーザのホームディレクトリに配置
default_mail_env = maildir:~/Maildir
  :
  :

[root@linux ~]# service dovecot start 
dovecot を起動中:                                          [  OK  ]

[root@linux ~]# chkconfig dovecot on 
[root@linux ~]# chkconfig --list dovecot 
dovecot         0:off   1:off   2:on    3:on    4:on    5:on    6:off