Message Attributes

Select message attributes you want to filter messages by. You can filter by sender, header, or message size.

Select one of the following attributes:

• Header: Check if the header value matches a regular expression, contains a substring, equals a value, or if the header exists or not.
• Source: Add IP addresses and domains to compare them with.
• Size: Set size limits for email attachments, the whole email, or both. Attachment size limits apply to individual attachments, not the total size of all the attachments.

After you've entered the attribute and its condition, click Add to include it in the list of filters.

Under Match for, if you've added multiple attributes, select how the rule evaluates them:

• Any: The rule matches if any of the attributes are true.
• All: The rule matches only if all attributes are true.

If you use a message attribute rule with another rule type, the match is against both types. For example, if you select message attribute for attachment size, and a keyword rule type, the rule is only matched if the attachment size limit is met and the keyword is found.

We calculate attachment size using the email's MIME-encoding. We don't use the size of the raw files. This means attachment file sizes are often reported as larger than the actual file. You must take this into account when filtering on attachment size. See Calculating email attachment file sizes.