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SquirrelMail Configuration Easy Steps (SquirrelMail + Sendmail + Apache On RedHat/CentOS/Fedora)

This tutorial explains how you can install and configure SquirrelMail on a RedHat/CentOS/Fedora based mail server which uses Sendmail and Apache.


Primary Mail Server:  linuxbox4 (
Domain Name:
Trusted IP Pool:

Note:  Replace domain name and system name and IP according to your scenario.



1.  DNS is configured with proper MX record.
2.  All necessary packages/ softwares are installed.


Step 1:

Configure all service to start at boot time.

chkconfig sendmail on
chkconfig httpd  on
chkconfig dovecot on


Step 2:

Configure /etc/hosts file. In this scenario /etc/hosts file should look like this:    linuxbox4


Step 3:

Outgoing Mail Server Configuration (Sendmail):

Open /etc/mail/ file and change the following two lines.


DAEMON_OPTIONS(`Port=smtp,Addr=, Name=MTA')dnl 


dnl DAEMON_OPTIONS(`Port=smtp,Addr=, Name=MTA')dnl 
dnl FEATURE(`accept_unresolvable_domains')dnl

Save and exit.

– First line here enables sendmail to receive incoming emails on all installed the NICs. Otherwise mail server would only be able to receive mails from it.

– Second line here tells sendmail, do not receive emails from mail servers whose PTR record is not configured in DNS server. This is a basic level SPAM control settings in sendmail.

Generate file from file.

m4 /etc/mail/ > /etc/mail/


Step 4:

Allow RELAY for trusts (organization’s) IP addresses that you want to permit sending emails using this mail server. Open /etc/mail/access in this file we specify all those addresses that will be sending emails through this mail server. At the end of this file add the following line:

192.168.0 RELAY

Save and exit and convert this text database into DB format by following command.

makemap hash access.db < access


Step 5:

Tell sendmail that it will be acting as a primary mail server for “” domain. We do this by adding domain name in /etc/mail/local-host-names. If this server is acting as a mail server for more then one domains then add names of all of the domains in this file on separate line. Open /etc/mail/local-host-names and add “” at the end of this file.

Note: A mail server can act as a primary mail server for more then one domains at the same time and as well as can act as a primary and secondary mail server for more than one domain at the same time.


Step 6:

All system users are mail users as well. Now create mail only users.

useradd -s /usr/sbin/smrsh mailuser1
useradd -s /usr/s2n/smrsh mailuser1

Also set their passwords:

passwd mailuser1
passwd mailuser2


Step 7:

Finally restart sendmail service.

service sendmail restart

Step 8:

Incoming Mail Server Configuration (Dovecot):

Open /etc/dovecot.conf and change the following lines.


#protocols = imap  pop3


protocols = imap imaps pop3 pop3s

Save and exit and restart dovecot service.

service dovecot restart



Step 9:

Webserver Configuration (Apache):

Apache  comes  pre-configured, you  just  have  to  change the ServerName parameter  in /etc/httpd/conf/httpd.conf  file and restart the service, that’s all. Open /etc/httpd/conf/httpd.conf  and set the ServerName parameter.


Save and exit and restart httpd service.

service httpd restart


Installation & Configuration of Squirrelmail    

•  Check that Squirrelmail is installed on the system.

# rpm –q squirrelmail

•  If squirrelmail is not installed on the system then install it through rpm:

# rpm –ivh squirrelmail

•  Now go to the squirrelmail directory, located in /usr/share.

# cd /usr/share/squirrelmail

•  Then go to the config directory:

# cd config

•  Now run one of the following commands to configure squirrelmail.

# ./



•  Now select option 1 (Organization Preferences).

Organization Name  :  YOUR_ORG_NAME
Organization Title  :  YOUR_ORG_NAME Webmail
Provider link    :  http://YOUR_ORG_SITE_ADDRESS
Provider name  :  YOUR_ORG_NAME

•  Now select option 2 (Server Settings). 

Domain                   :
Sendmail or SMTP :  Sendmail
IMAP Server          :  localhost
IMAP Port               :  143
Server software     :  uw
Delimiter                :  /

•  Now select option 3 (Folder Settings).

Default Folder Prefix                : mail/
Show Folder Prefix Option       : true 

Trash Folder                            : Trash
Sent Folder                              : Sent
Drafts Folder                           : Drafts
By default, move to trash        : true
By default, move to sent         : true
By default, save as draft          : true

List Special Folders First         : true
Show Special Folders Color    : true
Auto Expunge                          : true
Default Sub. of INBOX            : false
Show ‘Contain Sub.’ Option    : true
Default Unseen Notify             : 2
Default Unseen Type              : 1
Auto Create Special Folders   : true

Folder Delete Bypasses Trash  : false
Enable /NoSelect folder fix   : false

•  Now select option 4 (General Settings).

Data Directory                       : /var/lib/squirrelmail/prefs/
Attachment Directory            : /var/spool/squirrelmail/attach/
Directory Hash Level            : 0
Default Left Size                   : 150
Usernames in Lowercase     : false
Allow use of priority              : true
Hide SM attributions             : false
Allow use of receipts            : true
Allow editing of identity        : true
Allow editing of name          : true
Remove username from header : false
Allow server thread sort       : true
Allow server-side sorting     : true
Allow server charset search : true
Enable UID support             : true

PHP session name              : SQMSESSID
Location base                       :

•  Now choose option 8 (Plugins) and select the plugins that you wish to provide to your webmail users.

•  Now open the browser with the following link: