Filter, nofilter, destinationfilter, nodestinationfilter, sourcefilter, nosourcefilter, disablesourcefilter, disabledestinationfilter Channel Options

Filter file location
For the Messaging Server MTA, user and group Sieve filters are normally enabled simply by storing them in the users&#x27; (and groups&#x27;)  attribute - or more precisely, storing them in the attribute named by the    MTA option. However, user Sieve filters may be located in an alternate sort of location (in files on disk, for instance) via use of the  channel option. So while not normally used, in principle the  option may be used on the  , native, and   channels to specify the location of user Sieve filters for that channel. It takes a required URL argument describing the users&#x27; Sieve filter location -- typically a (templated, making use of substitution based on user)  file location. is the default; it means that only filters enabled implicitly via user/group LDAP entries will be used (and no additional, external Sieve lookup will be performed by the MTA).

IMPORTANT NOTE: Due to the way the MTA caches Sieves internally - the URL is used as a cache key - it&#x27;s vital that each user have a distinct Sieve file or be associated with a distinct LDAP entry when the  channel option is used. Failure to insure this separation will cause Sieve ownership checks to behave in unexpected ways and may allow users to bypass certain security checks.

The  and   channel options may be used on general MTA channels to specify a channel-level Sieve filter to apply to incoming and outgoing messages, respectively. (More precisely, a  is applied when the source channel on which it is specified is enqueueing a message; a   is applied when any channel is enqueuing a message to the destination channel on which it is specified.) These channel options take a required  URL  argument describing the channel Sieve filter location (typically a file). and  are the defaults and mean that no channel Sieve filter is enabled for either direction of the channel.   The obsolete  and   channel options are synonyms for   and , respectively.

IMPORTANT NOTE: It&#x27;s very important not to confuse the  and   channel options. The critical difference is that  Sieves are system-level whereas   Sieves are user-level. As such, a system-level Sieve invoked with  may not have access to the capabiities it needs, while a user-level Sieve invoked with   would give the user control over various aspects of message disposition handling they should not be able to change.

New in Messaging Server 7.0 update 3 are the  and   channel options. These options can be used to suppress the evaluation and interpretation of Sieve filters based on source or destination channel, respectively. Each option takes a single nonnegative integer argument, whose value is interpreted as follows:

See also:
 * ldap_filter MTA Option
 * Recipient access mapping tables
 * systemfilter MTA Option
 * Sieve filters
 * LDAP URL substitution sequences
 * MTA URL types
 * ims-ms channels
 * LMTP client TCPIP channels
 * Sieve filters and delivery flags channel options
 * Channel options