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 (192.168.0.14)
Domain Name: abc.com
Trusted IP Pool: 192.168.0.0/24
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.
Configure all service to start at boot time.
chkconfig sendmail on
chkconfig httpd on
chkconfig dovecot on
Configure /etc/hosts file. In this scenario /etc/hosts file should look like this:
192.168.0.14 linuxbox4 www.abc.com
Outgoing Mail Server Configuration (Sendmail):
Open /etc/mail/sendmail.mc file and change the following two lines.
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl FEATURE(`accept_unresolvable_domains')dnl
dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, 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 sendmail.cf file from sendmail.mc file.
m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf
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:
Save and exit and convert this text database into DB format by following command.
makemap hash access.db < access
Tell sendmail that it will be acting as a primary mail server for "abc.com" 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 "abc.com" 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.
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:
Finally restart sendmail service.
service sendmail restart