这次我们来学习Linux系统中的Sendmail服务器的配置。（邮件服务器的IP192.168.1.2 主机域名为mail.ltest.com）
前提：首先我们 把DNS服务器安装OK 能够解析，不明白的看http://www.cublog.cn/u/21675/showart_263507.html
1.首先安装Sendmail所需软件
[root@localhost ~]# rpm -q sendmail m4
sendmail-8.13.1-2
m4-1.4.1-16 已经默认安装了，还需挂载第4张光盘，安装与sendmail相关的软件
[root@localhost RPMS]# rpm -ivh sendmail-*
warning: sendmail-cf-8.13.1-2.i386.rpm: V3 DSA signature: NOKEY, key ID db42a60e
Preparing... ########################################### [100%]
1:sendmail-doc ########################################### [ 33%]
2:sendmail-cf ########################################### [ 67%]
3:sendmail-devel ########################################### [100%]
2.修改/etc/mail/local-hosts-name文件。
增加本地域和主机的FQDN，记住只是本地主机的FQDN和域名FQDN，不要添加其他域的，否则向外域发送邮件的时候会出现user unknown的错误：
[root@localhost named]# cat /etc/mail/local-host-names
# local-host-names - include all aliases for your machine here.
ltest.com
3.更改/etc/mail/sendmail.mc文件，修改下列地方：
DaemonPortsOptions=Port=smtp,Addr=127.0.0.1, Name=MTA 更改为：
DaemonPortsOptions=Port=smtp,Addr=yourip或者0.0.0.0, Name=MTA
然后m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
4.用户管理
认证的配置：修改/etc/mail/sendmail.mc中的字段，取消 “TRUST_AUTH_MECH”一行和下一行“define”处的注释。（于sendmail.mc文件的第48、49）然后m4 /etc/ mail/sendmail.mc>/etc/mail/sendmail.cf。
[root@localhost named]# chkconfig --list saslauthd 开启认证
saslauthd 0:off 1:off 2:off 3:off 4:off 5:off 6:off
[root@localhost named]# chkconfig --level 35 saslauthd on
建立用户帐号
[root@localhost named]# groupadd mailuser
[root@localhost named]# adduser -g mailuser -s /sbin/nologin mike
[root@localhost named]# adduser -g mailuser -s /sbin/nologin john
[root@localhost named]# passwd mike
[root@localhost named]# passwd john 密码都是123
设置邮件别名和邮件群发
修改/etc/aliases文件实现邮件转发和邮件列表：
admin: mike 为邮件用户mike设置别名admin
testgroup: mike,john 实现群发 发给testgroup的邮件发给mike 和 john 以上2个可以分别测试
#newaliases
5.访问控制设置
更改/etc/mail/accesss文件，增加：
[root@localhost named]# cat /etc/mail/access
# Check the /usr/share/doc/sendmail/README.cf file for a description
# of the format of this file. (search for access_db in that file)
# The /usr/share/doc/sendmail/README.cf is part of the sendmail-doc
# package.
#
# by default we allow relaying from localhost...
localhost.localdomain RELAY
localhost RELAY
127.0.0.1 RELAY
ltest.com RELAY
完成后makemap hash /etc/mail/access.db < /etc/mail/access进行数据库更新。
6.#service sendmail restart
[root@localhost named]# service sendmail restart 启动服务
Shutting down sendmail: [FAILED]
Starting sendmail: [ OK ]
Starting sm-client: [ OK ]
[root@localhost named]# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
220 localhost.localdomain ESMTP Sendmail 8.13.1/8.13.1; Sat, 17 Mar 2007 12:54:47 +0800
ehlo localhost
250-localhost.localdomain Hello localhost.localdomain [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-AUTH DIGEST-MD5 CRAM-MD5 LOGIN PLAIN ---认证应该生效
250-DELIVERBY
250 HELP
quit
221 2.0.0 localhost.localdomain closing connection
Connection closed by foreign host.
7.安装邮局服务
[root@localhost RPMS]# rpm -ivh dovecot-0.99.11-2.EL4.1.i386.rpm --aid
warning: dovecot-0.99.11-2.EL4.1.i386.rpm: V3 DSA signature: NOKEY, key ID db42a60e
Preparing... ########################################### [100%]
1:perl-DBI ########################################### [ 20%]
2:postgresql-libs ########################################### [ 40%]
3:mysql ########################################### [ 60%]
4:dovecot ########################################### [ 80%]
5:perl-DBD-MySQL ########################################### [100%]
把1-5这些软件都安装完毕才可以继续下去呢，，，，
[root@localhost /]# vi /etc/dovecot.conf在protocols = imap imaps 后添加pop3 pop3s
启动dovecot服务
[root@localhost /]# service dovecot restart
Stopping Dovecot Imap: [FAILED]
Starting Dovecot Imap: [ OK ]
[root@localhost /]# chkconfig --level 35 dovecot on
OK了 我们使用客户机测试。
