이 Messaging Server 릴리스의 새로운 기능

(54) A new facility has been added to store information 
that previously would
	have gone in the general, forward, and reverse databases in the compiled
	configuration instead. A new MTA option, USE_TEXT_DATABASES, has been
	added to control this capability. This option is bit encoded. If bit
	0 (value 1) is set the file IMTA_TABLE:general.txt is read as the MTA
	configuration is initialized and the information from that file replaces
	all uses of the general database. If bit 1 (value 2) is set the file
	IMTA_TABLE:reverse.txt is read and used in instead of the reverse
	database. Finally, if bit 2 (value 4) is set the file
	IMTA_TABLE:forward.txt is read and used instead of the forward
	database. The default value for this option is 0, which disables all
	use of text databases. Note that use of the text database option
	means that changes to the underlying files will only be seen after
	a cnbuild, and in the case of running processes, after a reload.

Several additional MTA options can be used to set the initial size of
the various text database tables:
   
GENERAL_DATA_SIZE - Initial number of entries in the general text database.
REVERSE_DATA_SIZE - Initial number of entries in the reverse text database.
FORWARD_DATA_SIZE - Initial number of entries in the forward text database.

The MTA stores the database template strings in string pool 3, so the
STRING_POOL_SIZE_3 MTA option controls the  initial allocation of space
for this purpose.
   
Note that these various options only control initial sizes; the
various tables and arrays will resize automatically up to the
maximum allowed size. The maximum string pool size in 6.2P8 and
earlier is 10Mb, after 6.2P8 is has been increased to 50Mb. Up
to 1 million entries are allowed in 6.2P8 and earlier, this has
been increased to 2 million entries in later releases.


(144) A new MTA option, USE_CANONICAL_RETURN, has been added. This option
is bit-encoded with the various bits matching those of the USE_ORIG_RETURN
option. Each place where the MTA performs a comparison operation against
	the envelope from (MAIL FROM) address has an assigned bit. If the bit
	in USE_CANONICAL_RETURN is clear normal rewriting is applied to the
	envelope from address prior to use. In particular rewriting from
	mailAlternateAddress attributes to mail attributes will be performed;
	mailEqvuialentAddress attributes won't be rewritten to the corresponding
	mail attribute. If, however, the bit is set, the corresponding address
	will be rewritten if it appears in a mailEquivalentAddress attribute.

	 It should be noted that the bit USE_ORIG_RETURN will, if set, disable
	rewriting entirely. So setting a bit in USE_ORIG_RETURN makes the
	corresponding bit in USE_CANONICAL_RETURN a noop.

	 Note that the various bits of USE_ORIG_RETURN don't appear to be
	documented at this time, so here's a list of them:

Bit	 Value	 Usage
0	 1	 When set, use the original envelope From: address in
			 ORIG_SEND_ACCESS mapping table probes
1	 2	 When set, use the original envelope From: address in
			 SEND_ACCESS mapping table probes
2	 4	 When set, use the original envelope From: address in
			 ORIG_MAIL_ACCESS mapping table probes
3	 8	 When set, use the original envelope From: address in
			 MAIL_ACCESS  mapping table probes
4	 16	 When set, use the original envelope From: address in mailing
			 list [AUTH_LIST], [MODERATOR_LIST], [SASL_AUTH_LIST], and
			 [SASL_MODERATOR_LIST] checks
5	 32	 When set, use the original envelope From: address in mailing
			 list [CANT_LIST] and [SASL_CANT_LIST] checks
6	 64	 When set, use the original envelope From: address in mailing
			 list [AUTH_MAPPING], [MODERATOR_MAPPING], [SASL_AUTH_MAPPING],
			 and [SASL_MODERATOR_MAPPING] checks
7	 128	 When set, use the original envelope From: address in mailing
			 list [CANT_MAPPING] and [SASL_CANT_MAPPING] checks
8	 256	 When set, use the original envelope From: address in mailing
			 list [ORIGINATOR_REPLY] comparisons
9	 512	 When set, use the original envelope From: address in mailing
			 list [DEFERRED_LIST], [DIRECT_LIST], [HOLD_LIST], and
			 [NOHOLD_LIST]	checks
10	 1024	 When set, use the original envelope From: address in mailing
			 list [DEFERRED_MAPPING], [DIRECT_MAPPING], [HOLD_MAPPINGS],
			 and [NOHOLD_MAPPING] checks
11	 2048	 When set, use the original envelope From: address in mailing
			 list checks for whether the sender is the list moderator
12	 4096	 When set, use the original envelope From: address in mailing
			 list LDAP_AUTH_DOMAIN LDAP attribute (e.g.,
			 mgrpAllowedDomain) checks
13	 8192	 When set, use the original envelope From: address in mailing
			 list LDAP_CANT_DOMAIN LDAP attribute (e.g.,
			 mgrpDisallowedDomain) checks
14	 16384	 When set, use the original envelope From: address in mailing
			 list LDAP_AUTH_URL LDAP attribute (e.g.,
			 mgrpAllowedBroadcaster) checks
15	 32768	 When set, use the original envelope From: address in mailing
			 list LDAP_CANT_URL LDAP attribute (e.g.,
			 mgrpDisallowedBroadcaster) checks
16	 65536	 OBSOLETE. In Messaging Server 5.0 and Messaging Server 5.1, when set use the original
			 envelope From: address in mailing list LDAP_MODERATOR_RFC822
			 comparisons; since as of Messaging Server 5.2 there is no longer any such
			 global MTA option nor need for such an attribute (since the
			 LDAP_MODERATOR_URL attribute value can, in fact, specify a
			 mailto: URL pointing to an RFC 822 address), this bit no
			 longer has any meaning.
17	 131072	 When set, use the original envelope From: address in mailing
			 list LDAP_MODERATOR_URL LDAP attribute (e.g., mgrpModerator)
			 comparisons
18	 262144	 When set, use the original envelope From: address in any
			 source-specific FORWARD mapping tables probes
19	 524288	 When set, use the original envelope From: address in any
			 source-specific FORWARD database probes

	Bit 0 is the least significant bit.

(145) The SPAMFILTERn_OPTIONAL MTA options now accept two additional values: -2
	and 2. -2 and 2 are the same as 0 and 1 respectively except that they also
	cause a syslog message to be sent in the event of a problem reported by
	the spam filter plugin.

(146) Old-style mailing lists defined in the aliases file or aliases database now
	accept a nonpositional [capture] parameter. If used the [capture] parameter
	specifies a capture address with the same semantics as capture addresses
	specified by the LDAP_CAPTURE attribute applied to a user or group in LDAP.

(147) The default value for the MISSING_RECIPIENT_POLICY MTA option has been changed
	from 2 (add envelope recipient list as a To: field) to 1 (ignore missing
	recipient condition). This brings Messaging Server in line with what RFC 2822 recommends.

(148) Although it will rarely make sense to do so, the x_env_to keyword can now
	be used without also setting single on a channel.

(149) The MTA now has the ability to process multiple different LDAP attributes
	with the same semantics. Note that this is not the same as processing of
	multiple values for the same attribute, which has always been supported.
	The handling attributes receive depends on the semantics of the attribute.
	The possible options are:

	 (a) Multiple different attributes don't make sense and render the user
		entry invalid. In 6.2 and later this handling is the default for
		all attributes unless otherwise specified.
	 
	(b) If multiple different attribute are specified one is chosen at random
		and used. LDAP_AUTOREPLY_SUBJECT, LDAP_AUTOREPLY_TEXT, and
		LDAP_AUTOREPLY_TEXT_INT all receive this handling in 6.2 only; in
		6.3 and later they receive the handling described in item 153 below.
		6.3 adds the LDAP_SPARE_3 and LDAP_PERSONAL_NAME attribute to this
		category. Note that this was how all attributes were handled prior
          to 6.2.
	 
	(c) Multiple different attributes do make sense and should all be acted
		on. This handling is currently in effect for LDAP_CAPTURE,
		LDAP_ALIAS_ADDRESSES, LDAP_EQUIVALENCE_ADDRESSES and
		LDAP_DETOURHOST_OPTIN. Note that LDAP_DETOURHOST_OPTIN attribute
		was first added to Messaging Server in 6.3.
	 
(150) The MTA now has the ability to chose between multiple LDAP attributes
	and attribute values with different language tags and determine the
	correct value to use. The language tags in effect are compared against
	the preferred language information associated with the envelope from
	address. Currently the only attributes receiving this treatment are
	LDAP_AUTOREPLY_SUBJECT (normally mailAutoReplySubject),
	LDAP_AUTOREPLY_TEXT (normally mailAutoReplyText), LDAP_AUTOREPLY_TEXT_INT
	(normally mailAutoReplyTextInternal), LDAP_SPARE_4, LDAP_SPARE_5,
	LDAP_PREFIX_TEXT and LDAP_SUFFIX_TEXT.

	 It is expected that each attribute value will have a different language
	tag value; if different values have the same tag value the choice between
	them will be essentially random.

151) The length of URLs that can be specified in a mapping URL lookup has been
	increased from 256 to 1024. The same increase also applies to expressions
	evaluated by mappings and mapping calls to other mappings.

(152) A new MTA option, LOG_REASON, controls storage of error reason information
	in log records. Setting the option to 1 enables this storage, 0 (the
	default) disables it. This information, if present, appears just before
	diagnostic information in log records.

(153) A :percent argument has been added to spamtest. If present it changes the
	range of the spamtest result from 0-10 to 0-100. See the Internet Draft
	draft-ietf-sieve-spamtestbis-05.txt for additional information on this
      change.

(154) The SpamAssassin spam filter plugin's DEBUG option setting now accepts an
	integer value instead of a boolean 0 or 1. The larger the value the more
	debugging will be generated. In particular, a setting of 2 or greater
	reports exactly what was received from spamd.

(155) The conversion mapping now allows a new "PREPROCESS" directive. If specified
	it allows charset conversions to be done on messages prior to sending them to
	the conversion channel.

(156) The $. metacharacter sequence can now be used in a mapping or rewrite
	rule to establish a string which will be processed as the mapping entry
	result in the event of a temporary LDAP lookup failure. By default
	temporary LDAP failures cause the current mapping entry to fail.
	This is problematic in cases where different actions need to be taken
	depending on whether the LDAP lookup failed to find anything versus the
	directory server being unavailable or misconfigured.  The temporary
	failure string is terminated by an unescaped ".". In the case of mappings
	once a failure string has been set using this construct it will remain
	set until current mapping processing is completed. Rewrite rules behave
	differently; a temporary failure string remains set only for the duration
	of the current rule. "$.." can be used to return to the default state
	where no temporary failure string is set and temporary LDAP failures
	cause mapping entry or rewrite rule failure. Note that all errors other
	than failure to match an entry in the directory are considered to be
	temporary errors; in general it isn't possible to distinguish between
	errors caused by incorrect LDAP URLs and errors caused by directory
	server configuration problems.

(157) Setting the LOG_FORMAT MTA option to 4 now causes log entries to be
	written in an XML-compatible format. Entry log entry appears as
	a single XML element containing multiple attributes and no subelements.
	Three elements are currently defined, en for enqueue/dequeue entries, co
	for connection entries, and he for header entries.

	 Enqueue/dequeue (en) elements can have the following attributes:

	ts - time stamp (always present)
	no - node name (present if LOG_NODE=1)
	pi - process id (present if LOG_PROCESS=1)
	sc - source channel (always present)
	dc - destination channel (always present)
	ac - action (always present)
	sz - size (always present)
	so - source address (always present)
	od - original destination address (always present)
	de - destination address (always present)
	de - destination address (always present)
	rf - recipient flags (present if LOG_NOTARY=1)
	fi - filename (present if LOG_FILENAME=1)
	ei - envelope id (present if LOG_ENVELOPE_ID=1)
	mi - message id (present if LOG_MESSAGE_ID=1)
	us - username (present if LOG_USERNAME=1)
	ss - source system (present if bit 0 of LOG_CONNECTION
		is set and source system information is available)
	se - sensitivity (present if LOG_SENSITIVITY=1)
	pr - priority (present if LOG_PRIORITY=1)
	in - intermediate address (present if LOG_INTERMEDIATE=1)
	ia - initial address (present if bit 0 of LOG_INTERMEDIATE
		is set and intermediate address information is available)
	fl - filter (present if LOG_FILTER=1 and filter information
		is available)
	re - reason (present if LOG_REASON=1 and reason string is set)
	di - diagnostic (present if diagnostic info available)
	tr - transport information (present if bit 5 of LOG_CONNECTION
		is set and transport information is available)
	ap - application information (present if bit 6 of LOG_CONNECTION
		is set and application information is available)

		Here is a sample en entry:
en ts="2004-12-08T00:40:26.70" pi="0d3730.10.43" sc="tcp_local"
	dc="l" ac="E" sz="12" so="info-E8944AE8D033CB92C2241E@whittlesong.com"
	od="rfc822;ned+2Bcharsets@mauve.sun.com"
	de="ned+charsets@mauve.sun.com" rf="22"
	fi="/path/ZZ01LI4XPX0DTM00IKA8.00" ei="01LI4XPQR2EU00IKA8@mauve.sun.com"
	mi="<11a3b401c4dd01$7c1c1ee0$1906fad0@elara>" us=""
	ss="elara.whittlesong.com ([208.250.6.25])"
	in="ned+charsets@mauve.sun.com" ia="ietf-charsets@innosoft.com"
	fl="spamfilter1:rvLiXh158xWdQKa9iJ0d7Q==, addheader, keep"

      Here is a sample co entry:

co ts="2004-12-08T00:38:28.41" pi="1074b3.61.281" sc="tcp_local" dr="+"
       ac="O" tr="TCP|209.55.107.55|25|209.55.107.104|33469" ap="SMTP"/

      Header (he) entries have the following attributes:

        ts - time stamp (always present, also used in en entries)
        no - node name (present if LOG_NODE=1, also used in en entries)
        pi - process id (present if LOG_PROCESS=1, also used in en entries)
        va - header line value (always present)

      Here is a sample he entry:

he ts="2004-12-08T00:38:31.41" pi="1074b3.61.281" va="Subject: foo"/

(158b) Added list authorization policy values SMTP_AUTH_USED and AUTH_USED.
       These are similar in effect to the old SMTP_AUTH_REQUIRED and AUTH_REQ
       but unlike the old values do not require posters to authenticate.
 
(159) Sieve errors are now logged as such in mail.log when LOG_FILTER is
      enabled.
 
(160) The ALLOW_TRANSACTION_PER_SESSION limit kicked in one transaction too
      early; it now allows the specified number of transaction instead of one
      less.
 
(161) The type of transport protocol in use (SMTP/ESMTP/LMTP) is now logged
      and made available to the various access mappings. In particular, two
      new modifier characters have been added to the set that can appear after
      an action indicator in the mail.log* files:
 
      E - An EHLO command was issued/accepted and therefore ESMTP was used
      L - LMTP was used

	Previously the only modifier characters that would appears were A
 	(SASL authentication used) and S (TLS/SSL used).

 	Additionally, the $E and $L flags respectively will be set as
 	appropriate for the various *_ACCESS mappings.

(162) Wildcards are now allowed in the strings used to match verdicts
 	returned by spam filters.

 (163) imsimta encode now supports three new switches:

      -disposition=VALUE	   Sets the content-disposition to the specified
                                   VALUE
 	-parameters=NAME=VALUE	   Specifies one or more additional content-type
                                   parameters and their values
 	-dparameters=NAME=VALUE	   Specifies one or more additional content-disposition
                                   parameters and their values

 	(164) Bit 4 (value 16) of the DOMAIN_UPLEVEL MTA option is now used to
 	control whether address reversal rewriting is:

 	(1) Skipped if the address is a mailEquivalentAddress (bit clear)
 	(2) Performed only if the address is a mailAlternateAddress (bit set)

 	(165) A value "/" given as an [envelope_from] nonpositional alias parameter,
 	as an errors to positional alias parameter, or as a value of the
 	mgrpErrorsTo LDAP attribute is now interpreted as a request to
 	revert to using the original envelope from address for the incoming
 	message while retaining mailing list semantics. This can be useful
 	for setting up mailing lists that report all forms of list errors
 	to the original sender.

(166) The Job controller directory sweep is now more sophisticated. Instead
 	of reading all the files in the queue directory in the order in which
 	they are found, it reads several channel queue directories at once.
 	This makes for much more reasonable behaviour on startup, restart, and
 	after max_messages has been exceeded.  The number of directories to be
 	read at once is controlled by the job controller option
 	Rebuild_Parallel_Channel. This can take any value between 1 and 100.
 	The default is 12.

 	(167) The sieve interpreter now keeps track of whether a response message was
 	generated by a notify or vacation action and logs this information as
 	needed.

      (168) Add the option Rebuild_In_Order parameter to the job_controller.	If
 	this is set to a non zero value, then on startup the job controller adds
 	previously untried (ZZ*) messages to the delivery queue in creation
 	order.  Previous (and default) behavior is to add the messages in the
 	order in which they are found on disk.  There is a cost associated with
 	recreating the queues in order.

     (169) Some additional reasons why a requested vacation response isn't sent
 	are now logged.

 	(170) Add the command imsimta cache -change command.  This command allows
 	certain job controller parameters to be changed on the fly.  The allowed
 	formats of this command are:

  	imsimta cache -change -global -debug=<integer>
 	imsimta cache -change -global -max_messages=<integer>
   imsimta cache -change -channel_template=<name> master_job=<command>
   imsimta cache -change -channel_template=<name> slave_job=<command>
   imsimta cache -change -channel=<name> master_job=<command>
   imsimta cache -change -channel=<name> slave_job=<command>
   imsimta cache -change -channel=<name> thread_depth=<integer>
   imsimta cache -change -channel=<name> job_limit=<integer>

   Changing parameters for a channel template (e.g. tcp_*) changes that
 	parameter for all channels derived from that template.

     (171) Add the command imsimta qm jobs.	This command displays what messages are
 	being processed by what jobs for what channels. Typical output might be:

   channel <channel name>
     job <pid>
       host <host name>
       host <host name>
         <count of hosts> HOSTS BEING PROCESSED BY JOB <pid>
       message <subdir/message name>
       message <subdir/message name>
       processed messages: <# messages sucessfully dequeued>
       failed processing attempts: <# messages reenqueued>
       <count of messages> MESSAGES BEING PROCESSED BY JOB <pid>
      <count of jobs> JOBS ACTIVE FOR CHANNEL foo
     <count of active channels> ACTIVE CHANNELS


	In the past they were only available to the various *_ACCESS mappings.

 	E - Incoming connection used ESMTP/EHLO.
 	L - Incoming connection used LMTP/LHLO.
 	F - NOTIFY=FAILURES active for this recipient.
 	S - NOTIFY=SUCCESSES active for this recipient.
 	D - NOTIFY=DELAYS active for this recipient.
 	A - SASL used to authenticate connection.
 	T - SSL/TLS used to secure connection.

(174) The buffer used for spamfilter verdict destination strings has been
 	increased in size from 256 to 1024 characters. This was done to
 	accomodate the much longer verdict destination strings that Brightmail
 	6.0 can return.

 	(175) Two new values now have meaning for the various SPAMFILTERx_OPTIONAL
 	MTA options: 3 and 4. A value of 3 causes spamfilter failures to
 	accept the message but queue it to the reprocess chanel for later
 	processing. A value of 4 does the same thing but also logs the
 	spam filter temporary failure to syslog.

 	(176) The ability to log the amouint of time a message has spent in the queue
 	has been added to the MTA logging facility. A new option, LOG_QUEUE_TIME,
 	enables this capability. Setting the option to 1 enables queue time
 	logging, while the default value of 0 disables it. The queue time is logged
 	as an integer value in seconds. It appears immediately after the application
 	information string in non-XML format logs. The attribute name in XML formatted
 	logs for this value is "qt".

 	(177) Source channel switching based on user or domain settings is now possible.
 	There are three new settings involved:

 	(a) A new channel keyword userswitchchannel. This keyword must be present
 	  on the initial source channel for user channel switching to occur.

 	(b) A new MTA option LDAP_DOMAIN_ATTR_SOURCE_CHANNEL that specifies the
 	  name of a domain-level attribute containing the name of the channel
 	  to switch to.

 	(c) A new MTA option LDAP_SOURCE_CHANNEL that specified is the name of a
 	  user-level attribute containing the name of the channel to switch
 	  to.

 	Additionally, the channel being switched to must be set to allow channel
 	switches, that is, it cannot be marked with the noswitchchannel keyword.

 	Switching is done based on information returned by rewriting the MAIL
 	FROM address. Note that MAIL FROM addresses are easily forged so this
 	functionality should be used with extreme care.

 	(178) List expansion in the context of the mgrpallowedbroadcaster LDAP attribute
 	now includes all the attributes used to store email addresses (normally
 	mail, mailAlternateAddress, and mailEquivalentAddress). Previously only
 	mail attributes were returned, making it impossible to send to lists
 	restricted to their own members using alternate addresses.

 	(179) The default for the GROUP_DN_TEMPLATE MTA option has been changed to
 	""ldap:///$A??sub?mail=*". It used to be ""ldap:///$A?mail?sub?mail=*".
 	This change makes the change described in item 178 work correctly in
 	the case of lists defined using DNs.

 	a domain-level attribute containing the default mailhost for the domain.
 	If set and the attribute is present on the domain the mailhost attribute
 	is no longer required on user entries in the domain. This option
 	currently has no default, but preferredmailhost is the logical attribute
 	to use as long as some other, conflicting usage doesn't exist.

 	(181) New channel keywords generatemessagehash, keepmessagehash, and
 	deletemessagehash. Generatemessage will, if specified on a destination
 	channel, cause a Message-hash: header field to be inserted into the
 	message. Keepmessagehash will cause any existing Message-hash: field
 	to be retained. Deletemessagehash will delete any existing Message-hash:
 	field. Deletemessagehash is the default.

 	The value placed in Message-Hash: fields is (obviously) a hash of the
 	message. Several new MTA options control how the hash is generated:

 	MESSAGE_HASH_ALGORITHM - The hash algorithm. Can be any of "md2",
 	"md4", "md5" (the default), "sha1", "md128" (for RIPE-MD128), or
 	"md160" (for RIPE-MD160).

 	MESSAGE_HASH_FIELDS - Comma separated list of fields from the header to
 	hash (in order). Any known header field can be specified. If this
 	option is not specified it defaults to "message-id,from,to,cc,bcc,
 	resent-message-id,resent-from,resent-to,resent-cc,resent-bcc,
 	subject,content-id,content-type,content-description".

 	(182) New MTA option UNIQUE_ID_TEMPLATE. This option specifies a template
 	used to convert an address into a unique identifier. The template's
 	substitution vocabulary is the same as that for delivery options.
 	The resulting unique identifier is intended for use by message
 	archiving tools.

 	(183) Per-user aliasdetourhost is now possible through the following set
 	of features:

    (a) Added a aliasoptindetourhost channel keyword. This is similar in
 	function to aliasdetourhost except detouring only occurs if the
 	user has opted in via the following attribute. The keyword's
 	value is a comma-separated list of potential detour hosts.

    (b) Added a LDAP_DETOURHOST_OPTIN MTA option, which specifies the name
 	of an attribute used to opt the user in to the detour (assuming of
 	course the source channel has aliasoptindetourhost set). If the
 	values of this attribute contain periods they will be compared
 	against the list of potential detour hosts and the first host
 	on the list that matches will be the chosen detour. If the
 	value doesn't contain a period the first detour host will be
 	used unconditionally.

    (c) Added a ALIASDETOURHOST_NULL_OPTIN MTA option. This is similar to
 	SPAMFILTERx_NULL_OPTIN - it specifies a "special" value which if
 	used in the optin attribute is treated as the same as the
 	attribute being omitted. The default valueis "", which means that
 	an empty attribute value is ignored.

 	(184) Support for a new IP_ACCESS table has been added. This access mapping
 	is consulted during SMTP client operations just prior to attempting to
 	open connections to a remote server. The mapping probe has the following
 	format:

 	source-channel|address-count|address-current|ip-current|hostname

 	source-channel is the channel the message is being dequeued from,
 	address-count is the total number of IP addresses for the remote
 	server, address-current is the index of the current ip address being
 	tried, ip-current is the current IP address, and hostname is the
 	symbolic name of the remote server.

 	The mapping can set the following flags:

 	$N - Immediately reject the message with an "invalid host/domain error"
           Any supplied text will be logged as the reason for rejection but
           will not be included in the DSN.

 	$I - Skip the current IP without attempting to connect.

 	$A - Replace the current IP address with the mapping result.

 	(185) The ACCESS_ORCPT MTA option has been changed from a simple boolean (0 or 1)
 	to a bit-encoded value. Bit 0 (value 1) has the same effect it always
 	had: It enables the addition of the ORCPT to all the various access mappings.
 	Bits 1-4 (values 2-16), if set, selectivey enable the addition to the
 	ORIG_SEND_ACCESS, SEND_ACCESS, ORIG_MAIL_ACCESS, and MAIL_ACCESS mappings
 	respectively.

 	(186) The new ACCESS_COUNTS MTA option provides a way to get at various types
 	of recipient count information in the various recipient *_ACCESS mappings.
 	ACCESS_COUNTS is bit-encoded in the same way as ACCESS_ORCPT now is (see
 	the previous item for specifics) and if set enables the addition of a
 	set of counts to the end of the access mapping probe string. Currently
 	the format of the count addition is:

 	RCPT-TO-count/total-recipient-count/

 	Note the trailing slash. It is expected that additional counter information
 	will be added to this field in the future; all mappings making use of this
 	information should be coded to ignore anything following the (current)
 	last slash or they may break without warning.

 	(187) Support for SMTP chunking (RFC 3030) has been added to both the SMTP
 	client and server. This support is enabled by default. Four new
 	channel keywords can be used to control whether or not chunking is
 	allowed. They are

 	chunkingclient - Enable client chunking support (default)
 	chunkingserver - Enable server chunking support (default)
 	nochunkingclient - Disable client chunking support
 	nochunkingserver - DIsable server chunking support

 	The log file action field has been extended to indicate whether or not
 	chunking was used to transfer a given message. Specifically, a C will
 	be appended if chunking is used. Note that ESMTP has to be used for
 	chunking to work, so you'll typically see field values like "EEC" or
 	"DEC".

 	(188) Support has been added for a new caption channel keyword. This keyword
 	is similar to the existing description channel keyword in that it takes
 	a quoted string as an argument that is intended for use in channel
 	displays. The difference is presumably that a "caption" is short than
 	a "description". JES MF appears to need both.

 	(189) A new utility routine has been written to verify domain-level Schema 1
 	and 2 information in the directory. This utilty routine is accessible
 	to user through a new verify command in the imsimta test -domain program:

 	% imsimta test -domain
 	DOMAIN_MAP> verify

 	Various checks are done by this utility, but the most important by far
 	is verification of canonical domain settings for domains with overlapping
 	user entries.

 	The verification utility can return the following fatal errors:

 	%DMAP-F-CANTGETDN, Cannot obtain DN of domain entry, directory error
 	%DMAP-F-INTDEFERROR, Internal defined flag error on domain '%.*s', aborting
 	%DMAP-F-INTHASHERROR, Internal hash error, aborting
 	%DMAP-F-INTTREESTRUCTERROR, Internal tree structure error, aborting

      These are all indicative of an internal error in the verification code
 	and should never occur.

 	The following domain errors can be reported:

 	%DMAP-E-ALIASTOOLONG, Domain alias '%s' in entry with DN '%s' is too long
 	%DMAP-E-BASEDNTOOLONG, Base DN pointer '%s' in entry for domain '%.*s' is too
                             long
 	%DMAP-E-CANONICAL, Overlapping domains '%.*s' and '%.*s' defined by entries
                         '%.*s' and '%.*s' have different canonical domains '%.*s'
                         and '%.*s'
 	%DMAP-E-CANONICALINVALID, Canonical domain '%.*s' defined/referenced by
                                domain entry with DN '%.*s' is syntactically
                                invalid
 	%DMAP-E-CANONICALTOOLONG, Canonical name '%s' in entry for domain '%.*s'
                                is too long
 	%DMAP-E-CANTCONVDCDN, Cannot convert DN '%s' in DC tree to domain name
 	%DMAP-E-CANTEXTALIAS, Empty alias pointer attribute in '%.*s' domain alias
                            entry
 	%DMAP-E-DOMAININVALID, Domain name '%.*s' defined/referenced by domain entry
                             with DN '%.*s' is syntactically invalid
 	%DMAP-E-DOMAINMULTDEF, Domain '%s' multiply defined by entries with DNs '%s'
                             and '%s'
 	%DMAP-E-DOMAINTOOLONG, Domain '%s' in entry with DN '%s' is too long
 	%DMAP-E-DOMAINUNDEF, Domain name '%.*s' referenced by domain entry with DN
                           '%.*s' never defined
 	%DMAP-E-EMPTYCANONICAL, Domain '%.*s' has an empty canonical name
 	%DMAP-E-INVALIDBASEDN, Base DN pointer '%.*s' in entry for domain '%.*s'
                             is not a valid DN
 	%DMAP-E-MULTICANONICAL, Multivalued canonical name in entry for domain
                              '%.*s', used value '%s' ignored '%s'
 	%DMAP-E-NOBASEDN, Domain '%.*s' has no base DN
 	%DMAP-E-EMPTYBASEDN, Domain '%.*s' has an empty base DN
 	%DMAP-E-NODOMAINNAME, Domain entry with DN '%s' does not have a domain
                            name

      The following warnings can be reported:

 	%DMAP-W-DISALLLOWEDATTR, Domain '%.*s' has a disallowed attribute '%s'
                               with value '%s'
 	%DMAP-W-DNTOOLONG, Domain entry DN '%s' is too long
 	%DMAP-W-EMPAPPSTAT, Domain '%.*s' has an empty application status
 	%DMAP-W-EMPDISALLLOWED, Domain '%.*s' has an empty disallowed attribute
                              '%s'
 	%DMAP-W-EMPDOMSTAT, Domain '%.*s' has an empty domain status
 	%DMAP-W-EMPUIDSEP, Domain '%.*s' has an empty UID separator
 	%DMAP-W-INVALIDAPPSTAT, Application status '%s' for domain '%.*s' is
                              invalid
 	%DMAP-W-INVALIDDOMSTAT, Domain status '%s' for domain '%.*s' is invalid
 	%DMAP-W-INVALIDUIDSEP, UID separator '%s' for domain '%.*s' is invalid
 	%DMAP-W-MULTDOMAINNAMES, Domain entry with DN '%s' has multiple domain
                               names, used value '%s' ignored '%s'
 	%DMAP-W-MULTIAPPSTAT, Multivalued application status in entry for domain
                            '%.*s', used value '%s' ignored '%s'
 	%DMAP-W-MULTIBASEDN, Multivalued base DN pointer in entry for domain
                           '%.*s', used value '%s' ignored '%s'
 	%DMAP-W-MULTIDOMSTAT, Multivalued domain status in entry for domain
                            '%.*s', used value '%s' ignored '%s'
 	%DMAP-W-MULTIUIDSEP, Multivalued UID separator in entry for domain '%.*s',
                           used value '%s' ignored '%s'
 	%DMAP-W-MULTIVALIAS, Multivalued alias pointer in entry for domain alias
                           '%.*s', used value '%s' ignored '%s'
 	%DMAP-W-NOBASEDNNODE, Base DN pointer '%.*s' in entry for domain '%.*s'
                            doesn't point at anything
 	%DMAP-W-NODOMAINNAME, Domain entry with DN '%s' has a blank domain alias
 	%DMAP-W-NOENTRIES, No domain entries found, aborting

      Additional messages will undoubtedly be added to this list over time.

      
(190) The ability to generate :addresses arguments to sieve vacation via an
 	LDAP autoeply attribute has been added to Messaging Server. The new MTA option
 	LDAP_AUTOREPLY_ADDRESSES provides the name of the attribute to use.
 	This option has no value by default. The attribute can be multivalued,
 	with each value specifying a separate address to pass to the
 	:addresses vacation parameter.

 	(191) The new LDAP_DOMAIN_ATTR_CATCHALL_MAPPING can now be used to specify
 	the name of a LDAP domain attribute. This option is not set by default.
 	If set the option specifies the name of a mapping which is consulted
 	when an address associated with the domain fails to match any user
 	entries. The format of the mapping probe is the same as that of the
 	forward mapping, and the USE_FORWARD_DATABASE MTA option controls the
 	format of the probe of this mapping in the same way as the forward
 	mapping. If the mapping sets the $Y metacharacter the resulting string
 	will replace the address being processed.

 	(192) The MTA now fetches the block limit associated with the envelope return
 	address and will set RET=HDRS if no return policy is specified and the
 	message size exceeds the block limit. This prevents nondelivery
 	reports for large messages from being undeliverable themselves. No new
 	options or settings are associated with this change.

(193) The $E metacharacter in a mapping template means "exit after processing
 	the current template". There are cases where it is desireable to exit
 	immediately without interpreting the rest of the template. The $+1E
 	metacharacter sequence now produces this behavior.

 	(194) Use of POP-before-SMTP via the MMP is now indicated in mail.log E records
 	by the addition of a "P" to the action code.

     (195) Use of POP-before-SMTP can now be checked in the various *_ACCESS mappings
 	(except PORT_ACCESS, which occurs before the necessary information has been
 	communicated to the server), the FORWARD mapping, and any domain catchall
 	mapping. The $P metacharacter flag is set if POP-before-SMTP is used.

 	(196) The restriction that the same attribute cannot be assigned to multiple
 	"slots" and hence can have multiple semantics during alias expansion
 	and address reversal.

 	(197) The internal separator character used to delimit multiple subject line
 	tag additions has been changed from space to vertical bar. This makes it
 	possible to add a tag containing spaces, as some spam filters want to do.
 	This change effectively prevents vertical bars from being used in tags,
 	but such usage is almost certainly nonexistant.

 	(198) The MIME specification prohibits the use of a content-transfer-encoding
 	other than 7bit, 8bit, and binary on multipart or message/rfc822 parts.
 	It has long been the case that some agents violate the specification
 	and encode multiparts and message/rfc822 objects. Accordingly, the Messaging Server
 	MTA has code to accept such encodings and remove them. However, recently
 	a different standards violation has shown up, one where a CTE field is
 	present with a value of quoted-printable or base63 but the part isn't

 	actually encoded! If the MTA tries to decode such a message the result
 	is typically a blank messages, which is pretty much what you'd expect.

 	Messages with this problem have become sufficiently prevalent that
 	two new pairs of channel keywords have been added to deal with the
 	problem - interpretation of content-transfer-encoding fields on
 	multiparts and message/rfc822 parts can be enabled or disabled.
 	The first pair is interpretmultipartencoding and
 	ignoremultipartencoding and the second is interpretmessageencoding and
 	ignoremessageencoding. The defaults are interpretmultipartencoding
 	and interpretmessageencoding.

 	(199) Several additional error messages the SMTP server either returns
 	or places in DSNs have been made configurable. The new options and
 	their default values are:

  ERROR_TEXT_MAILFROMDNSVERIFY		invalid/host-not-in-DNS return address not allowed
  ERROR_TEXT_INVALID_RETURN_ADDRESS	invalid/unroutable return address not allowed"  
  ERROR_TEXT_UNKNOWN_RETURN_ADDRESS	invalid/no-such-user return address
  ERROR_TEXT_ACCEPTED_RETURN_ADDRESS	return address invalid/unroutable but accepted anyway
  ERROR_TEXT_SOURCE_SIEVE_ACCESS	source channel sieve filter access error
  ERROR_TEXT_SOURCE_SIEVE_SYNTAX	source channel sieve filter syntax error:
  ERROR_TEXT_SOURCE_SIEVE_AUTHORIZATION source channel sieve filter authorization error
  ERROR_TEXT_TRANSACTION_LIMIT_EXCEEDED number of transactions exceeds allowed maximum"
  ERROR_TEXT_INSUFFICIENT_QUEUE_SPACE	insufficient free queue space available
  ERROR_TEXT_TEMPORARY_WRITE_ERROR	error writing message temporary file
  ERROR_TEXT_SMTP_LINES_TOO_LONG	lines longer than SMTP allows encountered; message rejected
  ERROR_TEXT_UNNEGOTIATED_EIGHTBIT	message contains unnegotiated 8bit

     (200) We're seeing cases of overly agressive SMTP servers which will issue a
 	"5xy bad recipient" response to the first RCPT TO and then disconnect
 	immediately. (This is of course a flagrant standards violation.) The
 	problem is Messaging Server treats this as a temporary error (which of course it
 	is) and tries later, only to get the same result. A better thing to
 	do which works around this server bug is to handle the one recipient
 	as bad and requeue any remaining recipients for a later retry.

 	(201) Two new actions are availabile to system sieves: addconversiontag and
 	setconversiontag. Both accept a single argument: A string or list of
 	conversion tags. Addconversiontag adds the conversion tag(s) to the
 	current list of tags while setconversiontag empties the existing list
 	before adding the new ones. Note that these actions are performed very
 	late in the game so setconversiontag can be used to undo all other
 	conversion tag setting mechanisms.

 	(202) A new MTA option, INCLUDE_CONVERSIONTAG, has been added to selectively
 	enable the inclusion of conversion tag information in various mapping
 	probes. This is a bit-encoded value. The bits are assigned as follows:

 	pos   value    mapping
 	0	1    CHARSET_CONVERSIOn - added as ;TAG= field before ;CONVERT
 	1	2    CONVERSION - added as ;TAG= field before ;CONVERT
 	2	4    FORWARD - added just before current address (| delim)
 	3	8    ORIG_SEND_ACCESS - added at end of probe (| delim)
 	4	16    SEND_ACCESS - added at end of probe (| delim)
 	5	32    ORIG_MAIL_ACCESS - added at end of probe (| delim)
 	6	64    MAIL_ACCESS - added at end of probe (| delim)

 	In all cases the current set of tags appears in the probe as a comma
 	separated list.

(203) The sieve envelope test now accepts "conversiontag" as an envelope
  	field specifier value. The test checks the current list of tags,
 	one at a time. Note that the :count modifier, if specified, allows
 	checking of the number of active conversion tags.

      This type of envelope test is restricted to system sieves. Also
 	note that this test only "sees" the set of tags that were present
 	prior to sieve processing - the effects of setconversiontag and
 	addconversiontag actions are not visible.

 	(204) Trailing dots on domains, e.g. "foo@bar.", are illegal in email but
 	have been tolerated in some contexts by Messaging Server for a long time. RFC 1123
 	points out that trailing dots are syntactically illegal in email but
 	notes that some convention needs to exist in user interfaces where
 	short form names can be used. Accordingly, it may be handy in contexts
 	like SMTP submission to be able to accept addresses with trailing dots,
 	remove the dot while attaching special semantics to its presence.

 	Accordingly, Messaging Server has modified in two ways: (1) Trailing dots are now
 	accepted by the low-level address parser, making it possible to use them
 	in context where they could not previously be used, like addresses
 	inside of group constructs. (2) Trailing dots, when specified will
 	cause a rewrite of the address with a trailing dot. If the rewrite
 	with a trailing dot isn't found or otherwise fails rewriting will
 	continue as before without the trailing dot.

 	(205) Metacharacter substitutions can now be specified in mgrpModerator,
 	mgrpAllowedBroadcaster and mgrpDisallowedBroadcaster attributes. In
 	particular, the various address-related metacharacter sequences ($A for
 	the entire address, $U for the mailbox part, $D for the domain part) refer
 	to the current envelope from address and can in some cases be used to
 	limit the results returned by the URL to entries that are likely (or
 	guaranteed) to match. This may make authorization checks much more
 	efficient.

 	The new MTA option PROCESS_SUBSTITUTIONS controls whether or not
 	substitutions are performed in various LDAP attributes that specify
 	a URL. This is a bit-encoded value, with the bits defined as follows:

 	Bit	Value
 	0		1		Enables substitutions in mgrpDisallowedBroadcaster if set
 	1		2		Enables substitutions in mgrpAllowedBroadcaster if set
 	2		4		Enables substitutions in mgrpModerator if set
 	3		8		Enables substitutions in mgrpDeliverTo if set
 	4		16	Enables substitutions in memberURL

      The PROCESS_SUBSTITUTIONS MTA option defaults to 0, meaning that all of
 	these substitutions are disabled by default.

 	Note that the information available for substitution varies depending
 	on whether the attribute is used for authorization checks or for actual
 	list expansion. For authorization attributes the whole address ($A),
 	domain ($D), host ($H), and local-part ($L) are all derived from the
 	authenticated sender address. In the case of list expansion attributes
 	all of these substitution values are derived from the envelope recipient
 	address that specified the list. In both cases, however, the subaddress
 	substitution ($S) is derived from the current envelope recipient address.

 	The ability to access subaddress information in list expansion URLs makes
 	it possible to define "metagroups", that is, a single group entry that
 	in effect creates an entire collection of different groups. For example,
 	a group with a mgrpDeliverTo value of:

 	  ldap:///o=usergroup?mail?sub?(department=$S)

 	would make it possible to send mail to every member of a given department
 	with an address of the form group+department@domain.com. Note that a
 	mechanism like a forward mapping could be used to alter the syntax if
 	subaddresses are seen as too difficult.

206) New MTA option LDAP_DOMAIN_ATTR_UPLEVEL. This option specifies the name of
      a domain-level attribute used to store a domain-specific uplevel value
      which overrides the value of the DOMAIN_UPLEVEL MTA option for this
      one domain.
 
      Note that this attribute is only consulted if the domain is looked up.
      This means that setting bit 0 of this value to 1 for a domain won't
      make subdomains of the domain match unless bit 0 of DOMAIN_UPLEVEL is
      also set. As such, the way to get subdomain matching for some domains
      but not others is to set bit 0 of DOMAIN_UPLEVEL (this enabling subdomain
      matches for all domains) then clear bit 0 of the attribute for the
      domains where you don't want uplevel matching to occur.
 
      (207) Rewrite rules can now be used to override the default ALIAS_MAGIC setting.
      Specifically, a construct of the form $nT, where n is an appropriate
      value for the ALIAS_MAGIC MTA option, overrides the setting for
      the domain when the rule matches during alias expansion.
 
      ((208) $U in a PORT_ACCESS mapping template can now be used to selectively
      enable channel level debugging.
 
      (209) In 6.2 and earlier the PORT_ACCESS mapping was only reevaluated by the
      SMTP server (as opposed to the dispatcher) when bit 4 (value 16) of
      the LOG_CONNECTION MTA option is set, SMTP auth is enabled, or both.
      Additionally, evaluation only occurred when an AUTH, EHLO, or HELO
      command was issued. This has now been changed; PORT_ACCESS is
      now evaluated unconditionally as soon as the SMTP server thread
      starts, before the banner is sent. PORT_ACCESS may be reevaluated
      with different transport information when proxying from the MMP is
      used.
 
      (210) A useful spam-fighting strategy is to delay sending the SMTP banner
      for a brief time (half a second, say), then clear the input buffer,
      and finally send the banner. The reason this works is that many
      spam clients are not standards-compliant and start blasting SMTP
      commands as soon as the connection is open. Spam clients that do this
      when this capability is enabled will lose the first few commands in
      the SMTP dialogue, rendering the remainder of the dialogue invalid.
 
      This feature has now been implemented in Messaging Server. It can be enabled
      unconditionally by setting the BANNER_PURGE_DELAY SMTP channel
      option to the number of centiseconds to delay before purging and
      sending the banner. A value of 0 disabled both the delay and purge.
 
      The PORT_ACCESS mapping can also be used to control this capability.
      Specifying $D in the template causes an additional argument to be
      read from the template result, after the mandatory SMTP auth
      rulset and realm and optional application info addition. This value
      must be an integer with the same semantics as the BANNER_PURGE_DELAY
      value. Note that any PORT_ACCESS mapping setting overrides the
      BANNER_PURGE_DELAY SMTP channel option.
 
      (211) Added channel keywords acceptalladdresses and acceptvalidaddresses.
      Keyword acceptvalidaddresses is the default and corresponds to the
      MTA's standard behavior where any recipient errors are reported
      immediately during the SMTP dialogue.  If the keyword acceptalladdresses
      is specified on a channel, then all recipient addresses are accepted
      during the SMTP dialogue. Any invalid addresses will have a DSN sent
      later.

   (212) Support has been added for postprocessing LDAP expansion results with
 	a mapping. The new LDAP_URL_RESULT_MAPPING MTA option can be used to
 	specify the name of a group attribute which in turn specifies the name of

 	a mapping. This mapping will be applied to any results returned by
 	expanding either a mgrpDeliverTo or memberURL attribute. The mapping
 	probe will be of the form:

 	LDAP-URL|LDAP-result

 	If the mapping returns with $Y set the mapping result string will replace
 	the LDAP result for alias processing purposes. If the mapping returns with
 	$N set the result will be skipped.

 	This mechanism can be used to define groups based on attributes that don't
 	contain proper email address. For example, suppose a company has placed
 	pager numbers in all their user entries. Messages can be sent to these
 	numbers via email by suffixing them with a particular domain. A group
 	could then be defined as follows:

 	(a) Define a new mgrpURLResultMapping attribute in the directory and
 	  set the  LDAP_URL_RESULT_MAPPING MTA option to this attribute's name.

 	(b) Define a page-all group with the following attributes:

            mgrpDeliverto: ldap:///o=usergroup?pagerTelephoneNumber?sub
            mgrpURLResultMapping: PAGER-NUMBER-TO-ADDRESS

 	(c) Define the mapping:

            PAGER-NUMBER-TO-ADDRESS

              *|*		"$1"@pagerdomain.com$Y

      Even more interesting effects can be acheived by combining this mechanism
 	with the PROCESS_SUBSTITUTION mechanism described in item 205 above. For
 	example, it would be easy to create a metagroup where sending to an
 	address of the form

 	pager+user@domain.com

 	sends a page to the user named "user".

 	(213) Setting the LOG_QUEUE_TIME MTA option to 1 now causes an additional field
 	to be selectively written to connection log records. This new field
 	appears immediately after any diagnostic information and is labelled
 	as "ct" in the XML-based log format. The value of this field is an
 	integer count of the number of seconds that elapsed when performing the
 	operation. So, for connection open ("O") records, the time shown is
 	the number of seconds needed to open the connection. For connection
 	close ("C") records it indicates the number of seconds the connection
 	was open. For connection failure records ("Y") the value indicates the
 	amount of time that was spent attempting to open the connection.

 	(214) "S" transaction log entries now increment the various submitted message
 	counters associated with the channel.

 	(215) The $( metacharacter in a FROM_ACCESS specifies that an address should
 	be read from the result string and used to replace the current overriding
 	postmaster address. $) has the same effect with the added constraint
 	that the overriding postmaster address must not be set prior to invoking
 	the mapping. This allows for specific postmaster addresses to be used
 	with addresses in nonlocal domains - domain postmaster addresses by
 	definition only work with locally defined domains. The override address
 	is (currently) the last string read from the FROM_ACCESS result prior to
 	reading any $N/$F failure result.

   (216) The capture sieve action now has two optional nonpositional parameter:
 	:dsn and :message. Only one of these can be specified in a single
 	capture action. :dsn is the default, and encapsulates the captured
 	message inside a special type of DSN. :message eliminates the
 	enacapsulation and behaves more like a redirect. But unlike redirect,
 	capture :message is only available to system sieves, always takes
 	effect even when a more specific sieve specifies some other sort of
 	action, and the envelope from address will be overridden with the
 	address of the sieve owner.

 	(217) The MTA now checks to make sure the UID attribute has a single value and
 	reports an alias expansion error if it does not. The UID attribute is
 	required to be single-valued in order to insure the user has a single,
 	unique mailbox.

 	(218) Two additional MTA options have been added to support more efficient
 	domain lookups from user base DNs. They are:

      LDAP_BASEDN_FILTER_SCHEMA1

	 String specifying filter used to identify Schema 1 domains when
		 performing baseDN searches. Default is the value of
		 LDAP_DOMAIN_FILTER_SCHEMA1 if that MTA option is specified.
		 If neither option is specified the default is
		 "(objectclass=inetDomain)".

      LDAP_BASEDN_FILTER_SCHEMA2

	String specifying additional filter elements used to identify
	 Schema 2 domains when performing baseDN searches. Default is the
	 value of LDAP_DOMAIN_FILTER_SCHEMA2 if that MTA option is specified.
	 If neither option is specified the default is an empty string.

      (219) A new MTA option MESSAGE_SAVE_COPY_FLAGS has been added to control how the
 	probes are constructed for the MESSAGE-SAVE-COPY mapping. If bit 0 (value
 	1) is  set it adds the transport and application information to the
 	beginning of the probe, if bit 1 (value 2) is set the original source
 	channel is added, if bit 2 (value 4) is set the most recent conversion
 	tag string is added. If all three bits are set the overall probe format is:

  transport|orig-source-channel|conversion-tags|queue-channel|return-address|D|filename

 	(220) The LDAP_OPTIN1 through LDAP_OPTIN8 MTA options specify attributes
 	for per-user optins to spam filtering based on destination addresses.
 	There are now 8 new MTA options, LDAP_SOURCE_OPTIN1 through
 	LDAP_SOURCE_OPTIN8, that provide comparable originator-address-based
 	per-user spam filter optins.

 	(221) Some additional switches have been added to imsimta test -rewrite:

   -saslused	 - Set internal flag indicating SASL authentication was used
 	-tlsused - Set internal flag indication TLS is in use
 	-esmtpused - Set internal flag indicating ESMTP is in use
 	-lmtpused - Set internal flag indicating LMTP is in use
 	-proxyused - Set internal flag indicating proxy authentication was used

 	Only -saslused and -tlsused are available in 6.2; the other depend on
 	other changes made in 6.3 and hence cannot be implemented in earlier
 	versions. -lmtpused and -esmtpused cannot be set at the same time.
 	-proxyused requires that -esmtpused or -lmtpused also be set.

(222) New LMTP channel option MAILBOX_BUSY_FAST_RETRY. If set to 1 (the default)
 	a 4.2.1 Mailbox busy error in response to LMTP message data is handled
 	by retrying the message after a random but short interval; normal
 	message backoff values do not apply. Setting the option to 0 disables
 	this behavior.