Email spoofing is the creation of an email with a forged sender address to intentionally mislead the recipient about its origin. This technique is often used in phishing campaigns and generally attempts to get a user to click a link and share their credentials or reply with sensitive information.
Z Services Cloud offers functionality to help prevent email spoofing. There are two types of From addresses in an email, both of which can be spoofed:
Envelope From: This is sent during the MAIL FROM command. Envelope From is straight forward to protect and isn't commonly used for legitimate mail to spoof. This is generally protected using SPF (Sender Policy Framework).
Mime-Encoded From: This is sent during the DATA command. It is not protected by any SMTP mechanism and as such is open to spoofing.
Go to Filter Rules > Anti-Spoofing Settings to access Z Services Cloud's anti-spoofing functionality. If you are a Domain Group Administrator, the Anti-Spoof Domains window displays showing a list of your domains:
Check the box to the left of the domain you want to edit and click the edit icon or Edit button. Check multiple boxes to edit multiple domains at once.
The Anti-Spoof Settings window displays for your selected domain(s). If you are a Domain Administrator, the Anti-Spoof window is your default view:
Follow the steps below to enable and modify your anti-spoof settings.
By default, anti-spoof settings are not enabled. Click Enable and the display expands:
Use SPF Record for IP Validation: Enable this option to use your SPF record to determine if a sender is valid instead of specifying IPs in the IP List. By default, this option is not enabled.
IP List: If you have not enabled Use SPF Record for IP Validation, you can add a list of CIDR notation ranges here that are allowed to send email using your domain. Click Add... to add an entry. Once added, click the edit icon to edit an IP, or the delete icon to delete an IP from the list.
Using IP List is more secure than using Hostname List. Generally, try to use Hostname List only if you are not using SPF and a service you are using has too many IPs to list.
Hostname List: Click Add... to enter hostnames that are allowed to send email using your domain, e.g. www.example.com.
Enter example.com to include any sub-domains such as support.example.com, mail.example.com, docs.example.com, etc.
Regular expression patterns can be used here, but are not necessary. If using regular expression, note that the more generic the expression, the easier it is to bypass spoofing.
If logged in as Domain Group Administrator and editing multiple domains, click Save to save changes to all domains and return to the Anti-Spoof Domains window.
If you do not click Save when editing multiple domains, only changes to the first domain checked will be saved.