2.2.1.1 PidTagBlockStatus Property

Type: PtypInteger32 ([MS-OXCDATA] section 2.11.1)

The PidTagBlockStatus property ([MS-OXPROPS] section 2.608) indicates whether the user's preference for viewing external content (such as links to images on a Hypertext Transfer Protocol (HTTP) server) is allowed or blocked in the message body.

A client can ignore this property and always allow or always block external content based on factors that are determined by the implementer. For example, a client can always allow or always block external content based on whether the sender is on a safe senders list. For information about the safe senders list, see the description of the PidTagJunkAddRecipientsToSafeSendersList property in [MS-OXCSPAM] section 2.2.2.1.

Valid values for this property are given in the following table.

Value

Meaning

0x00000000

Default value. Block external content.

Variable nonzero value

Allow or block external content, as described following this table.

If this property is used, the default (0x00000000) is to block the external content. However, if the value of this property falls within a specific range, as described in this section, viewing external content is allowed. The allowed value is computed from the PidTagMessageDeliveryTime property (section 2.2.3.9): because the sender of a message does not have knowledge of this value, the sender cannot reliably set the value of the PidTagBlockStatus property to the allowed values.

To compute the allowed values, convert the value of the PidTagMessageDeliveryTime property to a PtypFloatingTime ([MS-OXCDATA] section 2.11.1) type (floatdate), where the date is represented as the number of days from 00:00:00, December 30, 1899, Coordinated Universal Time (UTC). Apply the following formula.

result = ((floatdate - floor(floatdate)) * 100000000) + 3;

where floor(x) returns the largest integer ≤ x.

Convert the value result to a 32-bit integer computed value.

When a client first receives the message, it SHOULD set the value of the PidTagBlockStatus property to this computed value to allow external content. However, when determining whether to accept external content, clients SHOULD allow external content if the absolute value of the difference between the computed value and the value of the PidTagBlockStatus property is 1 or less. After the message is received and the value of the PidTagBlockStatus property has been calculated, clients SHOULD persist the value of this property for future reference.

The server MUST NOT alter the value of this property.

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