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Rule condition

The Rules condition wizard lets you add conditions for a rule. Select the condition Type and an Operation from the drop-down menu. The list of operations changes depending on what rule type you have chosen. Then select a Parameter. Parameter fields will change depending on the rule type and operation.

For example, choose File size > is greater than, and under Parameter specify 10 MB. Using these settings, any file that is larger than 10 MB will be processed using the rule actions you have specified. For this reason, you should specify the action taken when a given rule is triggered if you have not already done so when setting that rule's parameters.

If you want to import your custom list from a file instead of adding entries manually, right-click in the middle of the window and select Import from the context menu. Then you can browse for your file (.xml or .txt, and containing entries delimited by new lines) that you want to add to the list. Likewise, select Export from the context menu if you need to export your existing list to a file.

Alternatively, you can specify Regular expression by selecting Operation: matches regular expression or does not match regular expression.


note

ESET Mail Security uses std::regex. Refer to ECMAScript syntax for constructing regular expressions. Regular expression syntax is not case sensitive, including search results.


important

You can define multiple conditions. If you do so, all conditions must be met for the rule to apply. All conditions are connected using the logical operator AND. Even if most conditions are met and only a single one is not, the condition evaluation result is considered not met and the rule's action cannot be executed.

The following condition types are available for Mail transport protection, Mailbox database protection and On-demand mailbox database scan (some of the options might not display depending on your previously selected conditions):

Condition name

Mail transport protection

Mailbox database protection

On-demand mailbox database scan

Description

Subject

Applies to messages which contain or do not contain a specific string (or a regular expression) in the subject.

Sender

Applies to messages sent by a specific sender.

Envelope sender (SMTP sender)

MAIL FROM envelope attribute used during SMTP connection. Also used for SPF verification.

Sender's IP address

Applies to messages sent from a specific IP address.

Envelop sender's domain / Sender's domain

Applies to messages from a sender with a specific domain in their email addresses.

SMTP sender's domain

Applies to messages from a sender with a specific domain in their email addresses.

From header - address

"From:" value contained in message headers. This is the address that is visible to the recipient, but no checks are done to ensure that the sending system is authorized to send on behalf of that address. It is often used for spoofing the sender.

From header - display name

"From:" value contained in message headers. This is the display name that is visible to the recipient, but no checks are done to ensure that the sending system is authorized to send on behalf of that address. It is often used for spoofing the sender.

Recipient

Applies to messages sent to a specific recipient.

Recipient's organizational units

Applies to messages sent to a recipient of a specific organizational unit.

Recipient validation result

Applies to messages sent to a recipient validated in Active Directory.

Attachment name

Applies to messages containing attachments with a specific name.

Attachment size

Applies to messages with an attachment that does not meet a specified size, is within a specified size range, or exceeds a specified size.

Attachment type1

Applies to messages with a specific file type attached. File types are categorized in groups for easy selection, you can select multiple file types or whole categories. ESET Mail Security detects the actual file type regardless of the file extension. The same applies to the content of an archive.

Message size

Applies to messages with attachments that do not meet a specified size, are within a specified size range or exceed a specified size.

Mailbox

Applies to messages located in a specific mailbox.

Message headers

Applies to messages with specific data present in the message header.

Message body

Message body is searched for specified phrase. You can use the Strip HTML tags feature to remove HTML tags, attributes and values, and preserve text only. The body text will then be searched.

Internal message

Applies depending on whether a message is internal or not internal.

Outgoing message

Applies to outgoing messages.

Signed message

Applies to signed messages.

Encrypted message

Applies to encrypted messages.

Antispam scan result

Applies to messages flagged or not flagged as Ham or Spam.

Antivirus scan result

Applies to messages flagged as malicious or not malicious.

Anti-Phishing scan result

Applies to messages which were evaluated as phishing.

Received time

Applies to messages received before or after a specific date, or during a specific date range.

Contains password protected archive

Applies to messages with archive attachments that are protected by a password.

Contains damaged archive

Applies to messages with archive attachments that are damaged (most likely unable to open).

Attachment is password protected archive

Applies to attachments that are protected by a password.

Attachment is damaged archive

Applies to attachments that are damaged (most likely unable to open).

Folder Name

Applies to messages located in a specific folder, if the folder does not exist, it will be created. This does not apply to Public folders.

DKIM result

Applies to messages that passed or failed verification by DKIM, alternatively if not available.

SPF result

Applies to messages that the SPF evaluation result is:

Pass—the IP address is authorized to send from the domain (SPF qualifier "+").

Fail—SPF record does not contain the sending server or IP address (SPF qualifier "-").

Soft fail—the IP address may or may not be authorized to send from the domain (SPF qualifier "~").

Neutral—means the domain owner stated in the SPF record that they do not want to assert that the IP address is authorized to send from the domain (SPF qualifier "?").

Not available—SPF result of None means that no records were published by the domain or that no checkable sender domain could be determined from the given identity.

You can read RFC 4408 for more details about SPF.

If you use SPF result, whitelists within Filtering and verification are not taken into account for rules.

DMARC result

Applies to messages that passed or failed verification by SPF, DKIM or both, alternatively if not available.

Has reverse DNS record

Applies to messages with sender's domain that has reverse DNS record.

NDR result

Applies to messages that failed verification by NDR.

SPF result - From header

Applies to messages that the SPF evaluation result is:

Pass—the IP address is authorized to send from the domain (SPF qualifier "+").

Fail—SPF record does not contain the sending server or IP address (SPF qualifier "-").

Soft fail—the IP address may or may not be authorized to send from the domain (SPF qualifier "~").

Neutral—means the domain owner stated in the SPF record that they do not want to assert that the IP address is authorized to send from the domain (SPF qualifier "?").

Not available—SPF result of None means that no records were published by the domain or that no checkable sender domain could be determined from the given identity.

You can read RFC 4408 for more details about SPF.

If you use SPF result, whitelists within Filtering and verification are not taken into account for rules.

Envelope sender and From header comparison result

Compares the domain(s) contained in the "From:" email header field and Envelope sender against the domain lists.

SPF result HELO

Applies to messages that the HELO evaluation result is:

Pass—the IP address is authorized to send from the domain (SPF qualifier "+").

Fail—SPF record does not contain the sending server or IP address (SPF qualifier "-").

Soft fail—the IP address may or may not be authorized to send from the domain (SPF qualifier "~").

Neutral—means the domain owner stated in the SPF record that they do not want to assert that the IP address is authorized to send from the domain (SPF qualifier "?").

Not available—SPF result of None means that no records were published by the domain or that no checkable sender domain could be determined from the given identity.

You can read RFC 4408 for more details about SPF.

If you use SPF result, whitelists within Filtering and verification are not taken into account for rules.


note

1 The Attachment type rule condition has a known limitation where ESET Mail Security detection engine cannot detect extra small text files under 10 bytes in length in ASCII/ANSI encoding.

Condition type has the following Operations:

String: is, is not, contains, does not contain, matches, does not match, is in, is not in, in on the list, is not on the list, matches regular expression, does not match regular expression

Number: is less than, is greater than, is between

Text: contains, does not contain, matches, does not match

Date-time: is less than, is greater than, is between

Enum: is, is not, is in, is not in


note

If Attachment name or Attachment type is Microsoft Office file it is treated by ESET Mail Security as an archive. This means that its content is extracted and each file contained in the Office file archive (for example .docx, .xlsx, .xltx, .pptx, .ppsx, .potx) is scanned separately.

If you disable Antivirus protection in the Setup menu or Advanced setting (F5) > Server > Antivirus and Antispyware for Mail transport and Mailbox database protection layer, it will affect these rule conditions:

Attachment name

Attachment size

Attachment type

Antivirus scan result

Attachment is password protected

Attachment is damaged archive

Contains damaged archive

Contains password protected archive