1)Install the following packages on the server.
[root@server1 ~]#yum install sendmail-8.13.8-2.el5 [root@server1 ~]#yum install sendmail-doc-8.13.8-2.el5 [root@server1 ~]#yum install sendmail-cf-8.13.8-2.el5 [root@server1 ~]#yum install cyrus-sasl-lib-2.1.22-5.el5 [root@server1 ~]#yum install cyrus-sasl-devel-2.1.22-5.el5 [root@server1 ~]#yum install cyrus-sasl-gssapi-2.1.22-5.el5 [root@server1 ~]#yum install cyrus-sasl-2.1.22-5.el5 [root@server1 ~]#yum install cyrus-sasl-plain-2.1.22-5.el5 [root@server1 ~]#yum install cyrus-sasl-md5-2.1.22-5.el5 [root@server1 ~]#yum install dovecot-1.0.7-7.el5
2)Make sure that host name entries are correct in the /etc/hosts file.Entries will be like this:-
[root@server1 ~]# cat /etc/hosts 127.0.0.1 localhost.localdomain localhost 220.127.116.11 server1.openhelp.info. server1
3) Setup the RDNS for the server IP address.Here the IP address of the server is 18.104.22.168
Make sure that the forward and RDNS are setup correctly.
[root@server1 ~]# host 22.214.171.124 126.96.36.199.in-addr.arpa domain name pointer server1.openhelp.info. [root@server1 ~]# host server1.openhelp.info. server1.openhelp.info has address 188.8.131.52
4)Configure The /etc/resolv.conf FileCheck for the name server entries in the /etc/resolv.conf.
Entries will be like this:-
[root@server1 ~]# cat /etc/resolv.conf domain openhelp.info nameserver 184.108.40.206 nameserver 220.127.116.11The MX record for your domain must point to the IP address of the mail server.
5)Configure the send mail configuration file.For that you need to edit the /etc/mail/sendmail.mc file.
Make sure that the following lines are not commented:-
DAEMON_OPTIONS(`Port=smtp, Name=MTA')dnl dnl DAEMON_OPTIONS(`port=smtp,Addr=::1, Name=MTA-v6, Family=inet6')dnlComment out the SMART_HOST Entry in sendmal.mc.
The mail server doesn’t need a SMART_HOST entry in its sendmail.mc file.
Comment this out with a dnl at the beginning.
Execute the following command to regenerate sendmail.cf.
[root@server1 ~]#make sendmail.cf -C /etc/mailYou may also use the following command to generate a new sendmail.cf file:
[root@server1 ~]#m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
6)Configure access.dbMake sure that the following entries are there:-
[root@server1 ~]# cat /etc/mail/ access localhost.localdomain RELAY localhost RELAY 127.0.0.1 RELAY 18.104.22.168 RELAYThe IP address entries in the /etc/mail/ access can only relay mail throgh the server.
You’ll then have to convert this text file into a sendmail readable database file named /etc/mail/access.db.
Execute the following commands:-
[root@server1 ~]#cd /etc/mail [root@server1 ~]#make
7) The /etc/mail/local-host-names File:-The domain entries which is present in the /etc/mail/local-host-names can only receive the mails in the server.
Entries will be like this:-
[root@server1 ~]# cat /etc/mail/local-host-names openhelp.info server1.openhelp.info
The /etc/mail/virtusertable fileA virtusertable is a database that maps virtual domains into news addresses. With this feature, mail for virtual domain on your network can be delivered to local, remote, or a single user address.
[root@server1 ~]# cat /etc/mail/virtusertable email@example.com james firstname.lastname@example.org email@example.com @openhelp.info admin @tuxplanet.com tuxFirst column is the the target email address and the second column is the local user’s mail box or a remote email addressor a mailing list entry present in the in the /etc/aliases file to which the email should be forwarded.If matching entries are not there in the /etc/mail/virtusertable, then sendmail checks the email address in the /etc/aliases fle.After editing the file /etc/mail/virtusertable execute the commands:-
[root@server1 ~]#cd /etc/mail [root@server1 ~]#makeThese commands will convert the entries in the file /etc/mail/virtusertable to a sendmail-readable database file named /etc/mail/virtusertable.db
9)The /etc/mail/aliases fileThe aliases database contains a list of virtual mailboxes that are expanded to other user(s), files, programs or other aliases.
Here are a few examples that can be used in /etc/mail/aliases
[root@server1 ~]#cat /etc/mail/aliases root: jack hacker : john,mark, kat abuse:: /dev/null procmail: "|/usr/local/bin/procmail"The file format is simple; the mailbox name on the left side of the colon is expanded to the target(s) on the right. The first example simply expands the mailbox root to the mailbox jack,
which is then looked up again in the aliases database. If no match is found, then the message is delivered to the local user jack. The next example shows a mail list. Mail to the mailbox hacker is expanded to the three local mailboxes john,mark and kat . The next example shows writing mail to a file, in this case /dev/null. The last example shows sending mail to a program, in this case the mail message is written to the standard input of /usr/local/bin/procmail through a UNIX® pipe. When this file is updated, you need to run make in /etc/mail/ to update the database.
10)Configure saslauthdSaslauthd is a daemon process that handles plaintext authentication requests on behalf of the SASL library. The server fulfills two roles: it isolates all code requiring superuser privileges into a single process, and it can be used to provide proxy authentication services to clients that do not understand SASL based authentication.
By default authentication mechanism is the local shadow password file. But here we are using PAM.
Entries should be like this:-
[root@server1 ~]# cat /etc/sysconfig/saslauthd. # the default is "shadow", but we're using "pam" MECH=pam # these two settings are the defaults SOCKETDIR=/var/run/saslauthd FLAGS="-n 2"Check the /usr/lib/sasl2/Sendmail.conf file and make sure that the following entries are there:-
[root@server1 ~]# cat /usr/lib/sasl2/Sendmail.conf pwcheck_method:saslauthd
11)Make sure that saslauthd is started at boot time.
root@ [~]#chkconfig saslauthd on
12)Configure PAMMake sure that the following entries are there in /etc/pam.d/smtp
root@ [~]# cat /etc/pam.d/smtp auth required pam_stack.so service=system-auth account required pam_stack.so service=system-auth
13) Configure dovecotCheck the /etc/dovecot.conf file add/uncomment the following line:-
protocols = imap imaps pop3 pop3s
14)Restart the following services:-
[root@server1 ~]#/etc/init.d/saslauthd start [root@server1 ~]#/etc/init.d/sendmail start [root@server1 ~]#/etc/init.d/dovecot start