First, make sure the administrator email address is hosted at DreamHost. You can verify this by doing an MX record lookup on the following site:
Once you've confirmed your email is hosted with DreamHost, you can proceed with spoofing your FROM address in a useful manner.
Some WordPress contact forms created by plugins or themes have settings that let you completely control how emails are sent. Contact Form 7 is an example. You can use the plugin settings in the WordPress admin panel to send emails out with the name of the site visitor and an email address of a site admin, webmaster, or anyone associated with running the site:
- From: [your-name] <firstname.lastname@example.org>
You can also configure the Reply-To header so that replies to these emails will go directly to the site visitor:
- Reply-To: [your-name] <[your-email]>
There is a separate Configure SMTP plugin you can use to set the From information on all emails sent from WordPress, regardless of the plugin or theme that sends the email.
Additional WordPress information can be reviewed at WordPress troubleshooting contact forms. Please note however that not all plugins and themes allow you to control this.
The Contact Reply-To module changes Drupal's contact form to send from the website's email address. It also sets a reply-to header to the actual user, avoiding the restrictions discussed here.
Joomla has a "Custom Reply" that sends emails with the site visitor's from address. You can turn that off in the Joomla dashboard configuration. Go to 'Components -> Contacts -> Options'. On the Form tab, make sure the "Custom Reply" is set to NO.
If this is not done, Joomla may not even generate the email, and might result in the form being non-functional.
For Joomla versions 3.1 or higher, you can access the SMTP authentication settings in the Joomla dashboard at Site -> Global Configuration -> Server tab -> Mail Settings.
WooCommerce includes the option to change the sender from name and email address in the Settings -> Emails tab. This should be set to a DreamHost-hosted mail account.