Sieve: Editheader Extension

The editheader extension (RFC 5293) enables Sieve scripts to delete and add message header fields, thereby allowing interaction with other components that consume or produce header fields.

Configuration

The editheader extension is not available by default and needs to be enabled explicitly by adding it to sieve_extensions.

Settings

sieve_editheader_header

Default	[None]
Value	Named List Filter
See Also	Sieve editheader extension sieve_editheader_header_name sieve_editheader_header_forbid_add sieve_editheader_header_forbid_delete

Configures a new message header, which can be forbidden to be added or deleted. The filter name refers to the sieve_editheader_header_name setting.

sieve_editheader_header_forbid_add

Default	no
Value	boolean
See Also	Sieve editheader extension sieve_editheader_header

Forbid adding the sieve_editheader_header_name to the message header.

Addition of the Subject: header cannot be prohibited, as required by the RFC specification. Therefore, adding this header to this setting has no effect.

sieve_editheader_header_forbid_delete

Default	no
Value	string
See Also	Sieve editheader extension sieve_editheader_header

Forbid deleting the sieve_editheader_header_name from the message header.

Deleting the Received: and Auto-Submitted: fields is always forbidden, while removing the Subject: header cannot be prohibited, as required by the RFC specification. Therefore, using this setting with one of these headers has no effect.

sieve_editheader_header_name

Default	[None]
Value	string
See Also	Sieve editheader extension sieve_editheader_header

The name of the message header that is forbidden to be added or deleted.

sieve_editheader_max_header_size

Default	2k
Value	size
See Also	Sieve editheader extension

The maximum size in bytes of a header field value passed to the addheader command.

The minimum value for this setting is 1024 bytes.

Example

# Use editheader
sieve_extensions {
  editheader = yes
}

# Header fields must not exceed one kilobyte
sieve_editheader_max_header_size = 1k

# Protected special headers
sieve_editheader_header X-Verified {
  forbid_add = yes
  forbid_delete = yes
}
sieve_editheader_header X-Seen {
  forbid_delete = yes
}