Secure Sockets Layer (SSL) enables the HTTP protocol to be secured. This page will show you how to configure SSL in Apache and SquirrelMail.
Configuring Apache for SSL
2. Edit the file /etc/httpd/conf.d/ssl.conf and edit the lines below.DocumentRoot /usr/share/squirrelmail ServerName mail.acme.local:443 SSLCertificateFile /etc/pki/tls/certs/mail.acme.local.cert SSLCertificateKeyFile /etc/pki/tls/private/mail.acme.local.keyReplace mail.acme.local with your server name.
If you are using Red Hat Enterprise Linux 6 or CentOS 6, the generated certificate file will have a .crt extension instead of .cert.If you are not using Red Hat Enterprise Linux or CentOS, make sure the lines below are present.
LoadModule ssl_module modules/mod_ssl.so Listen 443
3. Restart the httpd service. Learn how to restart services here.
4. Try accessing SquirrelMail using https instead of http.You can force browsers to always use the SSL version. See Relocating SquirrelMail into the domain root.