xref: /csrg-svn/usr.sbin/sendmail/RELEASE_NOTES (revision 66338)

8.1C/8.1B	93/06/27
	Serious security bug fix: it was possible to read any file on
		the system, regardless of ownership and permissions.
	If a subroutine returns a fully qualified address, return it
		immediately instead of feeding it back into rewriting.
		This fixes a problem with mailertable lookups.
	CONFIG: fix some M4 frotz (concat => CONCAT)

8.1B/8.1A	93/06/12
	Serious bug fix: pattern matching backup algorithm stepped by
		two tokens in classes instead of one.  Found by Claus
		Assmann at University of Kiel, Germany.

8.1A/8.1A	93/06/08
	Another mailertable fix....

8.1/8.1		93/06/07
	4.4BSD freeze.  No semantic changes.

6.65/6.34	93/06/06
	Fix some lintish problems.
	Fix some cases where server SMTP behaved poorly when handed bogus
		input, pointed out by Eric Wassenaar.
	CONFIG: fix some more (sigh) mailertable bugs -- thanks to
		Motonori Nakamura of Kyoto University (again).

6.64/6.33	93/06/05
	Don't send 050 (-v) information after the 250 response to a QUIT
		command in srvrsmtp -- clients usually close the connection
		at this point, and it causes bogus error messages.
	Don't send messages that have errors on input (such as unbalanced
		parentheses) during SMTP transactions, since a return
		message has (probably) already been sent.
	Give better diagnostics on timeouts during network reads, including
		information similar to the SMTP phase.
	Fix bug that caused SMTP messages to deliver synchronously; this
		happened after the DATA 250, and hence caused reading the
		next command to be delayed.
	Ignore Errors-To: header unless 'l' (lower case el) header is
		specified.  The Errors-To: header violates RFC 1123.
		Errors-To: was only needed to take the place of the
		envelope sender in the days when most Unix mailers
		didn't understand about the two kinds of senders.
	Don't send warning messages in response to automatically generated
		messages (that is, those From:<>).
	CONFIG: fix some rather stupid typos in the mailertable code
		pointed out by Motonori Nakamura of Kyoto University.
	CONFIG: add confUSE_ERRORS_TO configuration option.
	CONFIG: if ALWAYS_ADD_DOMAIN is selected, try to use $M
		(masquerade name) instead of $j.
	CONFIG: don't add dots to relay names (added in 6.29); it breaks
		several things, and can be simulated by dot terminating
		the names of relays.  For example, use:
			DBbit.net.relay.
		(note the trailing dot).

6.63/6.32	93/06/01
	Fix prototypes to eliminate chars in argument lists -- some
		compilers are pissy about this.
	Log protocol ($r) and body type if set so we can determine if
		the adaptive algorithms are working.
	Pessimize on locking of database files (particularly for NEWDB
		databases) during opens.  There were problems with
		processes opening the file while it was rebuilt; since
		NEWDB caches heavily, the reader opened an empty file,
		which is an error.  If your system has the ability to
		lock atomically on open, this works properly; otherwise,
		there are race conditions.
	Check mod time on .pag file instead of .dir in NDBM aliases
		because the .dir file doesn't get updated for small
		alias files.  From John Gardiner Myers of CMU.
	More Solaris portability -- it now compiles on Solaris, but
		hangs up in gethostbyname().
	Move setting of RES_DEBUG flag before first myhostname() call
		so we can see name server traffic on that call.
	Fsync() queue files.
	Fix a problem that causes -bi to try to rebuild maps other than
		the alias file(s).
	Fix a problem that caused udb to reject entries from any but
		the first database listed.
	Rearrange doc subdirectory for 4.4BSD release tape.
	CONFIG: put $r into the Received line.  This was an oversight.
	CONFIG: fix typo (call to ruleset 99 should have been rulset 90).
	CONFIG: move "auxiliary" subroutines to be in ruleset 90-99
		range -- in the long run, single digit rulesets may
		become reserved for builtin use by sendmail.
	CONFIG: fix major problem that causes host aliases (that is,
		anything in $=w != $j) to not be recognized.  This has
		been around since 6.30.

6.62/6.31	93/05/28
	BETA RELEASE
	Fix recursive syserr (if there is an error printing a syserr
		message).  This makes the code much less eager to consider
		a write error as serious.  This also includes some
		heuristics to be clever about closed connections.
	Lock NEWDB files during gets.  This requires version 1.5 or later
		of the db library.  If you have an older version, you
		can use -DOLD_NEWDB.  This will go away in a few weeks.
	Fix problem causing aliases that use host maps to get overwritten.
	Do appropriate byte swapping on port numbers in ident protocol
		code.  Fix from Allan Johannesen of WPI.
	Defer opening of map files to the same time as alias files so that
		the daemon will tend to pick up new versions more promptly.
	Prototype a bunch more functions.
	Some Solaris 2.1 changes (still doesn't link though).
	Try to simplify Makefiles by including more subordinate #defines
		in conf.h (based on OS type).
	CONFIG: check for domains if FEATURE(mailertable) is defined.
		For example, if the host name is "knecht.cs.berkeley.edu"
		it will search the following mailertable keys:
			knecht.cs.berkeley.edu
			.cs.berkeley.edu
			.berkeley.edu
			.edu
		This could be used to replace the special relays for bitnet
		and similar nets.

6.61/6.30	93/05/24
	Fix problem that prevented appending dots on canonified host
		names.  This breaks tons of config files -- very
		important fix.
	Fix improper pointer dereference in response to HELO command.
	Fix core dump if debugging set in map_rewrite.
	CONFIG: add FEATURE(always_add_domain) to always attach the
		local domain (only impacts local mail).
	CONFIG: try to avoid turning names into $j -- although
		technically a host can only have one "canonical name",
		it seems to be common practice to have several.

6.60/6.29	93/05/22
	Major change: merge alias databases with maps.  This expands and
		changes the map class interface but fixes a bunch of bugs.
		The important user-visible change is that the file name
		in a K line now does not include the ".db" extension; this
		is added automatically.  Also, the -d (NIS domain) flag is
		missing from the K config line; use @domain instead.
		When compiling, the *_MAP names are gone -- just compile
		in NDBM, NEWDB, and/or NIS support.
	Announce mailer/host/user triple on -bv flag -- from Brian
		Bullen of Stirling University.
	Don't send more than one line in response to HELO -- it confuses
		Pony Express, which then behaves very badly.  However,
		this change does send two line 220 greetings, with the
		second line reading "ESMTP spoken here".  The usersmtp
		module recognizes this and goes into ESMTP mode regardless
		of the setting of the "a" mailer flag.  Thus, "a" means
		"always try EHLO".
	AIX portability changes (thanks to Christophe Wolfhugel of
		Herve Schauer Consultants (Paris) for providing me with
		an INSA account for this purpose).  Lightly tested.  Use
		-D_AIX3.  This probably breaks compatibility with some
		older systems (e.g., 4.2bsd) but still works on SunOS
		4.1.2, Ultrix 4.2A, HP-UX 8.07, OSF/1 T1.3, and AIX 3.2.3.
	Fix a problem causing an error message loop if the output channel
		is hosed.
	Add the Makefiles that I use for various environments -- some are
		Berkeley make versions and some are old make versions.
		My makefile for the NeXT box has gotten lost, alas!
	PRALIASES: support for printing NEWDB databases.  From
		Michael J. Corrigan of U.C. San Diego.
	CONFIG: don't pass pseudo-domains to $[ ... $] (if you have
		a wildcard MX it can have wierd results).  From
		Christophe Wolfhugel.
	CONFIG: dot terminate relay hostnames in S0.  From Christophe
		Wolfhugel.

6.59/6.28	93/05/13
	Log version with SMTP daemon startup message.
	Adjust setproctitle to work on NetBSD and BSD/386.
	Fix null pointer reference in MX fallback code.
	A bunch of minor fixes from Eric Wassenaar:
		If deliver cannot execv the mailer, return EX_OSERR
			instead of EX_TEMPFAIL (to give better
			error messages).
		Consistently malloc e_message.
		Catch degenerate case of calling returntosender()
			with an empty returnq.
		MIME reformatting.

6.58/6.28	93/05/13
	Fix bug that can cause incorrect verbose display of user smtp
		messages.
	Disable SMTP VERB command if PRIV_NOEXPN is set (since this
		could reveal the same information.
	Allow failure when reading SMTP greeting message to go on to
		next MX host.
	Add "MIME-Version: 1.0" header if using MIME (this was NOT
		included in RFC 1344, but Bill King of Allan-Bradley
		Company forwarded me email from Nathaniel Borenstein
		claiming that it was an inadvertent omission).
	Don't use Content-Type: X-message-header.  According to John
		Myers of CMU, many MIME readers will completely ignore
		the data if they don't recognize it.  Instead, just
		add a blank line to make it a legal (empty) message.
	Fix problem causing dots to keep getting appended to cached
		hostnames.  This can cause buffer overrun conditions.
		The problem was found by Erik Forsberg of Retix,
		although I used a different bug fix than he provided.
	Fix parsing of split header/envelope rewriting specs -- from
		Eric Forsberg.
	Fix from Eric Wassenaar to correct To: lists in error messages.

6.57/6.28	93/05/11
	Fix minor glitch causing extra ctladdrs to be output to queue
		file.  Just an annoyance.
	Cache results of name server canonification lookups to avoid
		backed up queue runs.
	Major rewrite of alias.c: considerable cleanup, plus sample
		(untested) support for NIS aliases.  The "A" option
		can now be a comma separated list (or be repeated) --
		that is, you can have multiple alias databases.  Each
		database can have the syntax ``class:file''; if no class
		is specified, the "implicit" class is assumed.  Implicit
		searches through a list of compiled in types -- hash,
		dbm, nis, and stab.  Alias files are searched in the
		order they are listed.  For example:
			OAhash:/etc/aliases.local,/etc/aliases
			OAnis:mail.aliases@my.nis.domain
		first searches the hash database /etc/aliases.local,
		then the regular /etc/aliases database, then the NIS
		map "mail.aliases" in the NIS domain "my.nis.domain".
	If in Verbose mode (probably from VERB command) run SMTP job
		in foreground and don't do RCPT optimizations.
	Add udb :mailsender as equivalent to owner- for regular aliases.
	Delete option 8; add option 7 that means the opposite.  That is,
		default to 8-bit mode; a special option is needed to
		force sendmail into 7 bit mode.
	Send error messages in encapsulated MIME format.
	New compile flag "NIS" that turns on NIS alias and NIS map
		support.
	Add "j" option to send error messages in MIME (RFC 1341)
		encapsulated message format per RFC 1344.  The
		syntax is pretty ugly if you don't have MIME-aware
		user agents.
	Clean up message handling (for display in mailq output).
	New setproctitle implementation for 4.4bsd.
	Create files (such as ~/dead.letter) using mode FileMode (the
		F option value) instead of 0666.
	Fix bug causing output of EXPN command to not be fully qualified.
		This may cause some problems with UUCP addresses that
		will require some config file assistance -- specifically,
		the $: part has to include the host name for this output
		to make sense.
	Fix a problem that sometimes diagnosed errors and still sent the
		message if the header syntax was bad.
	Fix a bug that caused an error message to be emailed when sendmail
		was operating in -bv mode.
	Add "ListenQueueSize" keyword to daemon options option (OO) to
		set the queue size parameter passed to listen().  You
		will normally have to tweak your kernel to up this.
	Strip spaces off of beginning of message-id before logging (in
		case it was folded across lines).
	Tweak compile flags in daemon.c -- there were some cases where
		it wouldn't work without NETINET.
	Change *file* mailer to output all the usual default headers
		(From, Date, Message-Id).  It gets used when sending
		back error messages.
	CONFIG: explicitly catch and diagnose list:; syntax in ruleset
		zero -- this is not a valid recipient syntax according
		to RFC 821.
	CONFIG: add confMIME_FORMAT_ERRORS to send error messages in
		MIME format.  Defaults to on.
	CONFIG: add SMTP_MAILER_FLAGS and UUCP_MAILER_FLAGS to augment
		the flags for those mailers.

6.56/6.27	93/05/01
	Fix problem that causes the fallback mail to postmaster
		(case ESM_POSTMASTER in savemail()) to not look at
		aliases (ugh).
	Some more HPUX tweaking (compile flag hpux => __hpux so it
		still works in ANSI mode).
	Don't try to flock non-regular files when mailing to a file.
		In particular, this was a problem if you tried to
		send to /dev/null.
	Fix a wierd bug that can cause senders to be queued as
		recipients if the name server is down when the mail
		is initially sent.  This hack just ignores sender
		deletion (essentially, it sets the MeToo flag) if there
		is a TEMPFAIL during processing of the sender address.
		Obscure.
	Fix a dangling else problem -- from Brian Bullen from University
		of Stirling, UK.
	Add the "b" mailer flag to force a blank line on the end of
		messages.  Some brilliant versions of /bin/mail insist
		on this but do not add it themselves.
	Add the "g" mailer flag to prevent user SMTP from sending
		"MAIL From:<>".  This is only intended to be a
		transitional gesture, and should not be used if at
		all possible.  It appears that Berkeley and IDA
		config files have always handled this properly; the
		UK config kit apparently does not.
	Don't lowercase and then capitalize header field names -- leave
		them with original capitalization.  Fixes from Bill
		King of Allen-Bradley Company.
	Further cleanup and improved reporting of error messages,
		particularly conditions that cause messages to be
		requeued for future delivery.
	Tweak syslog priorities in some cases.
	CONFIG: clean up route-addr on UUCP addresses.

6.55/6.25	93/04/27
	HPUX 8.07 compatibility changes in getla() -- I had to make
		these changes to get it to work at Berkeley, although
		others seem to have been working before (???).
	Various patches to XLA code.
	Fix problem that causes setuid bit on files to be ignored from
		SMTP or in queue runs.  Problem noted by Jason Ornstein
		of Under The Wire, Inc.
	Fix problem that can cause CNAMEs to be ignored.
	Generalize getmxrr to match local host in $=w instead of a
		single name passed in.
	Some cleanup from Eric Wassenaar:
		Use FileMailer instead of ProgMailer in two places.
		Eliminate duplicate 8th-bit stripping in commaize.
		Fix a problem with mis-parsing of backslash escapes
			under some circumstances.
	NIS map fix (was always including trailing null character)
		from Mike Glendinning of Ingres UK.
	Add "a" mailer flag to try using ESMTP.  It tries the EHLO
		command and if that fails falls back to regular SMTP.
		Also parses EHLO option keywords.  If host supports
		SIZE extension, this is added to the MAIL FROM:
		command.
	Extend "b" option to include a second value which is the
		maximum message size this server is willing to accept.
		For example, a value of "10/1000000" says that there
		must be ten blocks free, and sendmail will reject
		any message larger than one megabyte.
	Some portability hooks for NeXT (this could be applicable
		to Mach in general).  You have to create an empty
		file called "unistd.h" to get it to compile.
	Adjust config values (MAXLINE, MAXATOM, and PSBUFSIZE) to
		be more generous.
	Add X400-Received: to the list of headers tagged with H_TRACE
		in conf.c.  From Bill King, Allen-Bradley Co.

6.54/6.25	93/04/19
	Fix problem that caused redefinition of SMTP and QUEUE compile
		flags.  Pointed out by Jon Forrest of the Sequoia 2000
		project at Berkeley.
	Properly handle \! hack -- it was treating host\!user as one
		token (host!user) instead of three (host, !, user).
		Fix from Eric Wassenaar of NIKHEF-H.
	Fix compilation problem in getauthinfo() if IDENTPROTO is off.
	Turn off DEFNAMES and DNSRCH when getting the hostsignature
		(i.e., MX records) in level 1 configuration files; this
		matches the old behaviour.  From Motonori Nakamura of
		Kyoto University.
	Improve error message printing -- if sent through an alias,
		error messages include the name of the alias in the
		message.  Unfortunately, in order to make this work
		properly in queue runs, this changes the format of the
		C line in the qf file.  The relatively uselessness of
		the previous information was pointed out to me by
		Allan E Johannesen of WPI.
	Add XLA compile flag to add hooks to Christophe Wolfhugel's
		extended load average code.  This is still in very early
		form.  For information regarding the guts of the xla
		code, contact Christophe.Wolfhugel@grasp.insa-lyon.fr.
	Additional hooks for detecting tempfails in rewriting rules
		(that is, in map lookups).

6.53/6.25	93/04/15
	Properly diagnose ruleset zero returning null (instead of a mailer
		triple).  From Motonori Nakamura of Kyoto University.
	More generalization of socket code for other protocols.
	Shorten timeouts on reverse name lookups -- since they are done
		during connection establishment, long timeouts here can
		cause higher level timeouts.  This mainly serves to accept
		mail from hosts that do not have proper reverse (PTR) DNS
		records set up.
	Reset e_statmsg before each mailer invocation to avoid bogus
		messages in the log.
	Redefine $r, $s, and $_ in error envelopes so you don't get
		incorrect cruft in the error message.  Problem noted by
		Motonori Nakamura of Kyoto University.
	Fix a problem that can cause failure to return errors to Postmaster
		in certain cases.  From Motonori Nakamura.
	Fix a problem that can cause some systems to give duplicate error
		messages when a bad syntax address such as "<a" is presented
		to an SMTP server.   It doesn't seem to occur on all
		machines.  From Motonori Nakamura.
	Default IDENTPROTO off for Ultrix and HPUX, which apparently have
		the interesting "feature" that when they receive a "Host
		unreachable" message they closes all open connections to
		that host.  However, some firewall gateways send this message
		if you try to connect to an unauthorized port, such as the
		IDENT port (113).  Thus, no email can be received from such
		hosts.  There is some evidence that versions of Ultrix before
		4.3 do not have this problem.  Thanks to Tom Ivar Helbekkmo
		for pointing out this behaviour to me and to Michael Corrigan
		of U.C. San Diego for informing me about the HPUX problem.
	Allow IPC mailers to return a colon-separated list of hosts in the
		$@ clause; these are searched in order as though they were
		MX records.
	When sending an error report, print the list of addresses tagged
		as bad.  Requested by Allan E Johannesen of WPI.
	Change map function calls to return a status code.  This gets
		passed back as the result of rewrite.  Parseaddr marks
		the address as a QUEUEUP address if the return code is
		EX_TEMPFAIL.  All this to queue properly if the name
		server is down.  This code is not well tested.  This code
		changes the interface to map lookup functions (a fifth
		parameter, int *statp, is added).  Feature requested by
		Dan Oscarsson.
	Don't delete quotes (in the dequote map) if there are spaces in
		the string, since this would cause them to be replaced by
		the SpaceSub character.
	Accept BODY=8BITMIME on SMTP MAIL command.  This isn't advertised
		because the 8BIT to 7BIT translation doesn't exist yet.
		This does add a "bodytype" field to both envelope and
		queue file and a -B command line flag to pass the type in
		during direct invocations.
	Discard return error messages only on responses to responses to
		responses, not on responses to responses.  That is, the
		algorithm is to try return to sender, then return to
		postmaster, then discard.  Previously it discarded
		immediately if the return to sender pass failed.
	CONFIG: back out change to hide unqualified hostnames behind %-hack.
		This screws up local aliases and .forward files.
	CONFIG: add FEATURE(nocanonify) to turn off calls to $[ ... $];
		some sites only handle completely canonified names.
		Requested by John Gardiner Myers of CMU.
	CONFIG: some UUCP code was still included even if FEATURE(nouucp)
		was specified.

6.52/6.24	93/04/10
	Clean up some minor glitches on error return messages pointed out
		by Motonori Nakamura of Kyoto University.
	Fix reply() to not reset SmtpReplyBuffer on fatal errors; this
		was supposed to reset SmtpMsg Buffer.  This makes the
		client side code virtually useless.  Reported by Allan
		E Johannesen of WPI and Phil Brandenberger of Swarthmore.
	Better debug messages if fuzzy is disabled, suggested by Allan
		E Johannesen of WPI.
	Offset SmtpReplyBuffer by four in usersmtp when checking for
		loopback.  From Eric Wassenaar.
	Don't set $s until after runinchild in srvrsmtp -- otherwise
		it gets cleared.  From Eric Wassenaar.
	Implement IDA-style $&x for deferred macro expansion.
	More POSIX compatibility.
	CONFIG: Hide unqualified hostnames behind %-hack using $s as the
		actual sender.  This is only done if $r is non-null, that
		is, if this is not locally submitted mail.
	CONFIG: Add FEATURE(bitdomain) allowing mapping of BITNET host
		names to internet domains.  A program contributed by
		John Gardiner Myers of CMU to create the maps is included
		in the contrib directory (in the "misc" tar file).
	CONFIG: Add FEATURE(uucpdomain) for a similar mapping for UUCP
		hosts.  There is currently no tool to create this map.

6.51/6.23	93/04/04
	Add D= mailer flag to specify a path of possible working directories
		in which to execute the mailer.  This is intended for the
		prog mailer; some shells can get upset if they don't have
		access to the current directory.
	Add RFC 1413 (IDENT) protocol support.  This is only very loosely
		tested.  This adds a $_ macro to be the authenticated
		info (in ``user@domain [address]'' form) and debug flag
		9 to trace the protocol.
	Check for loopbacks in usersmtp instead of srvrsmtp -- there is no
		reason for a local agent to not be talking to the localhost
		(although the inverse is not true).
	Add a few hooks for automated map rebuilding.  This is certainly
		not done yet.
	CONFIG: Have prog mailer specify a path of ``D=$z:/'' -- that is,
		user's home directory then the root.
	CONFIG: Log RFC 1413 identification in Received: line.

6.50/6.22	93/04/01
	Fixes to requeueing code to make it compute priority, nrcpts,
		and the like properly.

6.49/6.22	93/04/01
	Diagnose incorrect privacy flags.  Suggested by Bryan Costales
		of ICSI.
	Some ANSI C fixes.
	Arrange to quote backslashes as well as other special characters
		in the phrase part of a route-addr.
	Some fixes to FallBackMX code suggested by Motonori Nakamura of
		Kyoto University.
	More vigorous zeroing of CurHostAddr to avoid logging of bogus
		host addresses when you are actually just printing
		information from the MCI structure; problem noted by
		Michael Corrigan of U.C. San Diego.
	Don't ignore rest of queue if any job is not runnable.  This can
		also cause an incorrect job to be lost.  Fix from
		Eric Wassenaar.
	Always respond "quickly" to RCPT command; do alias expansion and
		the like later.  This also means that mail for lists that
		have errors will be acccepted, and an error sent back
		later.  This is done by instantiating the queue file
		and then immediately running and requeueing it.

6.48/6.22	93/03/30
	Fix incorrect diagnosis of infinite loop in ruleset.  Problem noted
		by several people.
	Improve information printed when infinite loops are discovered.
	Zero CurHostAddr to fix erroneous internet addresses in log when no
		addresses can be bound.  Pointed out by Motonori Nakamura
		of Kyoto University.
	"Probe" SMTP connections using RSET instead of NOOP "just in case".
		Suggested by John Gardiner Myers of CMU.
	Don't warn about -f if you are setting sender to yourself.

6.47/6.22	93/03/29
	Fix incompatible call to endmailer in smtpquit which causes core
		dumps.  Noted by Allan E Johannesen of WPI.
	HPUX portability changes from Michael J. Corrigan of UC San Diego.
	Require MAIL before RCPT command in srvrsmtp.c.  This had been
		intentional from the 821 draft days when the order wasn't
		clear, but is silly now.
	Fix bug in nis_magic routine that was initializing parameters
		incorrectly.  Fix from Takahiro Kanbe of Fuji Xerox
		Information Systems Co., Ltd.
	Change default for PrivacyFlags in conf.c to 0 -- since it always
		"or"s in new values, there was no way to turn off the
		AuthWarning stuff.
	Add O option to set SMTP daemon options.
	Add V option to set fallback MX host.  This always sorts at lower
		priority than anything it gets from the name server.  It
		should only be used for environments with very bad network
		connectivity.  Requested by several people.
	Log sending info.  It's not clear this is a good idea.
	CONFIG: fix typo in mailertable code.  Noted by Phil Brandenberger
		of Swarthmore.
	CONFIG: add confDAEMON_OPTIONS and confFALLBACK_MX to set options
		O and V, respectively.

6.46/6.21	93/03/26
	Fix botch in server SMTP that broke transactions that did not
		use HELO first (like MH).  Fix from Michael Corrigan
		of U.C. San Diego.
	Fall back to other MX records if there is an error anywhere
		in delivery (actually on MAIL or DATA -- RCPT is harder).
		Suggested by John Gardiner Myers and Motonori Nakamura.
	Revert to non-prototypes -- it turns out that our ANSI C
		compiler is more forgiving than most others about
		mixing prototyped extern declarations with non-prototyped
		function definitions.
	Fix a problem with multi-word class matching pointed out by
		Neil Rickert.  Given:
			CX b a.b.c
			R$+ $=X $+	$: $1 < $2 > $3
		the input "user@a.b.c" failed instead of being properly
		rewritten as "user@a.<b>.c".
	Neil also convinced me that it was correct that $~ should match
		only one token -- the problem is that it's always possible
		to add another token, so $~ matches far too eagerly.

6.45/6.21	93/03/25
	Implement multi-word classes (properly!).

6.44/6.21	93/03/25
	Add X-Authentication-Warning: headers to clue users into possible
		attempts to forge mail.  This is on the authwarnings
		privacy flag, but is the default.  Suggested by Bryan
		Costales of ICSI.
	Pass default units for convtime in so they can be more reasonable.
	Allow config files to always add a new Comments: header (i.e.,
		they will be added even if an old one already exists).
		Suggested by Bryan Costales of ICSI.
	Allow config files to delete an existing Return-Path: header.
		These should only be added at final delivery.  Suggested
		by Bryan Costales of ICSI.
	Some debugging additions.  Suggested by Bryan Costales of ICSI.
	Clean up logging of Family 0 addresses.  Noted by David Muir
		Sharnoff and others.
	Add a "dequote" map class.  This allows config files to strip
		quotes off of addresses.  Note that this is not a builtin
		map, just a class -- so you have to define the map
		using the K line.
	Fix a bug in the queueup() loop getting a locked tf where in
		very odd cases it can fall off the bottom and core dump.
		Of course, it was P{r Emanuelsson who found it....
	Open a new transcript when splitting an envelope.  Problem found
		by Allan E Johannesen of WPI.
	Improved error output in endmailer if the mailer core dumps.
	CONFIG: Fix typo in UUCP mailer definition.
	CONFIG: Default several of the new options on: eight bit input,
		privacy flags set to "authwarnings", and message warning
		set to 4h.
	CONFIG: Use dequote map.

6.43/6.20	93/03/23
	Fix problem with assumption of an sa_len field in a generic
		sockaddr -- it turns out that most vendors haven't
		picked up this (very important) fix.
	Change compilation flags for daemon code -- select one or both
		of NETINET or NETISO, but don't ever set DAEMON manually.
	CONFIG: add FEATURE(mailertable) to do IDA-style mailertables.

6.42/6.19	93/03/19
	Use Postmaster as default fallback return address, not root.
	POSIX changes for file descriptor handling.
	Diagnose errors writing new queue file.
	If you change the owner using an owner- alias, also change the
		error mode to EM_MAIL so that errors don't get dropped
		into an inappropriate directory.  Problem noted by
		Allan E Johannesen of WPI.
	If you are su'ed to root, send email as who you really are, not
		as root.  From Brian Kantor of U.C. San Diego.
	Allow warning messages to be sent after a configurable interval
		has passed without delivery.  The message is sent only
		once per envelope.  This changes the format of the qf
		file to have an F line, and the format of the T option
		to accept take the format "return/warn" (both intervals).
	Don't force all local names to lower case -- this was left over
		from the wierd handling of case mapping on aliases.  It
		is now driven (as expected) by the "u" mailer flag.
		Problem noted by P{r Emanuelsson.
	Fix problem that caused headers on returned email to be trashed;
		they were getting freed, but are still accessible via
		BlankEnvelope.
	Fix problem that caused bogus ids to be created on returned
		mail.
	Add support for ISO and other non-INET networking.  This is by
		no means finished yet.  This does assume a lot of other
		system support, like a version of gethostbyname that
		returns non-AF_INET addresses.
	CONFIG: change default on prog mailer to keep upper case in
		user names (i.e., in the program command line).
	CONFIG: strip trailing dots off of hosts in uucp mailer before
		convert to bang format.
	CONFIG: create new "relay" mailer for $R (LOCAL_RELAY) and $H
		(MAIL_HUB) delivery that doesn't add local domain.  Note
		that this violates 821, but is probably "more correct"
		for what we are trying to do.  Problem pointed out by
		Michael Graff of Iowa State.

6.41/6.18	93/03/18
	Clean up unnecessary creates of queue ids (i.e., empty qf files)
		when not needed, such as when starting up an SMTP
		connection.
	Fix problem where split envelopes aren't instantiated in the queue.
		This is quite a serious bug.
	Owner- aliases had problems with leading spaces causing a
		premature delimitation.

6.40/6.18	93/03/18
	Have ending 250 (after DATA) include the id; suggested by
		Brian Kantor of UC San Diego.
	Add logging on envelope splitting.
	Change queue ids to have one more letter encoding the hour of
		the day so that during a single day there is a greater
		likelihood of uniqueness; requested by Brian Kantor.

6.39/6.18	93/03/18
	Fix minor compile problem if LOCKF is defined.
	Define size of tobuf in conf.h.  Observed by Toshinari Takahashi
		of Toshiba.
	Restore e_sender -- this is equivalent to e_from.q_paddr without
		decorations such as angle brackets and comments.
	OSF/1 on Alpha changes from Allan E Johannesen of WPI.
	CONFIG: fix typo in S3 for list syntax (;: => :;).  Thanks to
		Christopher Hoover for noting the problem.

6.38/6.17	93/03/17
	Pass envelope to disconnect to avoid another use of CurEnv, which
		can apparently end up being null at inopportune times.
	Log "received from" as "relay=" for consistency (suggested by
		John Gardiner Myers).
	Fix major bug in header handling:  if no From: line existed in
		the header (so sendmail inserts one), and the sender is
		an alias that has an owner, the From: line shows the
		owner (as well as the envelope).  Fixed by early binding
		the headers (which will change debugging output).
	HPUX portability patches from Michael J. Corrigan of UC San Diego.
	Some attempts to adapt better to out of open file conditions.
	Some changes to ctladdr handling in queue files.

6.37/6.17	93/03/16
	MAJOR CHANGE:  delete e_sender and e_returnpath (why are these
		different from e_from?) and $< macro.
	Log correct IP address in relay= field even if the connection
		times out.
	Log "received from [RESPONSE]" on EF_RESPONSE messages (from
		John Gardiner Myers).
	Fixes to SysExMsg logging (sometimes just got "message: %s"
		instead of "message: error message"), noted by Eric
		Wassenaar.  Also reported by Motonori Nakamura.
	Improvements to MX piggybacking code, from Motonori Nakamura.
	Fix case where CurHostName points to an auto variable that has
		been deallocated (from Motonori Nakamura).
	Fix bug causing newlines to be included in aliases if option
		"n" (check alias RHS) is set; bug noted by David Muir
		Sharnoff.
	Fix problem causing user names that should be mapped to lower
		case to not be mapped if they are sent during a queue
		run.  This greatly simplifies the case mapping code.
		Problem noted by Allan E Johannesen of WPI.
	Don't do recipient address rewriting in buildaddr.  This
		improperly did recipient rewriting on sender addresses,
		and just seems bogus in general -- but the change could
		break some .cf files.
	Pass TZ envariable to child processes for System V.
	CONFIG: allow LOCAL_RULE_1 and LOCAL_RULE_2 if you want to
		define those rulesets.
	KNOWN PROBLEM:  I have seen some problems on SunOS that causes
		the User Data Base to give errors on some addresses.  I
		have tracked the problem back at least as far as 93.02.15
		(version 6.22).  Running with debugging on makes it
		go away, so I conclude that it is referencing uninitialized
		stack data.  I haven't been able to track this down yet.

6.36/6.16	93/03/08
	Allow local mailer to specify $@host -- this lets you assign the
		"foo" part of jgm+foo to $h for passing in to the local
		mailer.
	Additional debug printing in getcanonname (show query type).
	Don't add the e_fromdomain on sender addresses -- this interacts
		wierdly with the owner- code.
	Improve delivery logging to not log obvious or meaningless stuff.
	Include numeric IP address in Received: lines per RFC 1123 section
		5.2.8.
	Fixed a bug in checking stat() return value if restrictmailq is
		set.  Also, check the entire group set instead of just the
		primary group.  Both from John Gardiner Myers.
	Don't have usrerr automatically print errno, since this is often
		misleading.
	Use transienterror() in makeconnection after connect() fails and
		in openmailer after execve() fails (from Eric Wassenaar).
		Also moved transienterror() from util.c to conf.c.
	Clean up from= logging on response messages.
	Undo patch allowing prescan to return a null vector -- it breaks
		too many things.
	Config: FEATURE(notsticky) lets you use UDB for everything coming
		in to the machine, even if it is specifically targetted
		to this machine.  Without it, UDB is bypassed if the user
		name is fully qualified.
	Config: fix another minor botch with <> (local mailer wasn't
		mapping them properly).

6.35/6.15	93/03/05
	Fix getrealhostname to return null if sinlen <= 0 -- this can
		occur if stdin is a pipe.
	Avoid infinite loop in getcanonname if name server return
		NO_DATA (for example).
	Config: avoid having C flag qualify list syntax and error syntax.

6.34/6.14	93/03/05
	Fix logging in deliver to not pass too many parameters to Ultrix
		versions of syslog.
	Don't write the pid file until after the daemon has actually
		opened and conditioned the connection.
	Consider addresses "different" if their q_uids differ (so that
		two users forwarding to the same program will be seen
		as different, rather than the same).
	Fix problem with bad parameters in main() -- they set ExitStat
		but don't exit.
	Fix null pointer references through RealHostName -- painfully
		discovered by Allan E Johannesen of WPI.
	Fix bug causing user@@localhost to core dump (yuch).
	Config: don't put two @host.dom.ain on users in $=E in SMTP
		mailer.  Also, catch user@ (no host) in ruleset 0.

6.33/6.13	93/03/03
	Config: add confCW_FILE as the name of the cw configuration file
		(defaults to /etc/sendmail.cw).  From P{r Emanuelsson.
	Allow prescan to return a pointer to an empty list -- this is
		not an error.  Also, clean up error reporting to avoid
		double errors (prescan reports once, then the caller
		reports again).
	Changes to avoid trusting T_ANY queries -- run them, but if you
		don't get the info you expected, do T_A and T_MX queries
		anyhow.  This also fixes an oversight where _res.options
		bits were being ignored.
	If PRIV_NOVRFY is set, use 252 response code instead of 502 per
		RFC 1123 section 5.2.3.  It's not 100% clear that this
		is correct, but it probably works better with stupid
		mailers that do a VRFY and only check the first digit.

6.32/6.12	93/03/02
	Fix uninitialized variable "protocol" in smtp code.
	Include <unistd.h> in sendmail.h -- move towards POSIX/ANSI.
	Additional hooks for RFC 1427 (ESMTP SIZE extension).  This
		includes requiring that enoughspace() know the system
		block size, which will undoubtedly break most ports.
	Trace flag 19 in use for srvrsmtp.c.
	Additional logging -- notably the sending mailer name.  This
		also changes the delivery logging to strict field=value
		syntax.
	Fix some problems with messages getting sent even to addresses
		that had been marked bad -- from Eric Wassenaar.
	More WIDE changes: accept host name inside [...] as non-MXed
		host.  This is intended ONLY for use inside firewalled
		environments, where the MX points at the gateway.
	Change .cf file conventions so that mapping for <> addresses
		don't have an @ in them (to avoid confusing the C mailer
		flag).  Pointed out by Neil Rickert.
	Config extensions for Sam Leffler's FlexFAX software.

6.31/6.10	93/02/28
	Fix some more bugs in alias owner code -- there were some wierd
		cases where an error in a non-aliased name would override
		the return info in an aliased name with an owner.
	Changes from WIDE Project, forwarded to me by Motonori Nakamura:
		Log actual delivery host (after MX et al); from
			yasuhiro@dcl.co.jp.
		Log daemon startup.
		Deliver Postmaster copies without a body.
		Better logging of SMTP senders.
		Send all program email as daemon even when local.
	As requested in various forms from many people, accept -qIstring
		to limit queue runs to jobs with queue-id matching string.
		Similarly for -qRstring for recipients, -qSstring for
		senders.
	Initial hooks for ESMTP support (see RFC 1425).
	Fixed a syntax error in the UUCP mailer specification that caused
		core dumps on startup.
	Check for missing A= or P= arguments in mailer definitions.

6.30/6.10	93/02/27
	Require FROZENCONFIG compilation flag to include frozen
		configuration code.  Frozen configuration is really
		not a very good idea any more, particularly in shared
		library environments.
	Do better checking of errno after opens of :include: and .forward
		files to defer delivery on network and other transient
		errors.  Suggestion from Craig Everhart.
	Fix minor botch in read timeout macro processing.
	Add FEATURE(nouucp) to config files for sites that know absolutely
		nothing about UUCP.
	Add built cf files to distribution tape and clarify how to build
		them if you don't have the Berkeley make.
	Some sizeof(long) portability changes for the Alpha, from Allan
		E Johannesen.
	Add "restrictmailq" privacy flag -- if set, only people in the same
		group as your queue directory can print the queue.  If you
		set this, be sure you also restrict access to log files....
	Fix another bug in owner-list stuff that can cause data files to
		be "lost".
	Fix a bug with queue runs that cause forwards to yourself to go
		into alias/forwarding loops.  I'm still iffy about this
		fix.
	Fix from Eric Wassenaar for suppression of return message code.

6.29/6.9	93/02/24
	Fix yet another problem in alias owner code -- put the wrong return
		address on the enclosed return-to-sender letter.

6.28/6.9	93/02/24
	Fix botch in alias owner code that caused it to not operate if the
		error was detected locally.

6.27/6.9	93/02/24
	M_LOCAL => M_LOCALMAILER to avoid conflict with Ultrix include
		file <sys/mount.h>.
	Miscellaneous bug fixes from Eric Wassenaar:
		sendmail -bv -t logs the from line even though in verify
			mode only.
		sendmail -v can go into queue mode if shouldqueue returns
			TRUE.
	Add route-addr pruning per RFC 1123 section 5.3.3.  This can be
		disabled using the "R" option.
	Delete (always undocumented) -R flag (save original recipients);
		there are ways to syslog(3) these now.
	Clean up SMTP reply codes -- specify them as needed in the code,
		instead of in conf.c -- this was needed during the NCP to
		TCP transition, but seems silly now.  This also changes
		parameters to message and nmessage.
	Have mailstats read the .cf file to find the sendmail.st file and
		get text versions of mailer names.  An initial version of
		this code was provided by Tuominen Keijo (although the
		comments indicate the good bits were written by "E.V.").
	Add yet more System V compatibility hacks.
	Fix bug in VRFY code (assumes everything must be a local user).
	Allow specification of any of the hard-wired pathnames in the
		Makefile.
	Delete concept of "trusted users" -- this really didn't provide
		any security anyway, and caused some problems.
	Delete last vestige of support for the word "at" as an equivalent
		to the character "@".
	Propagate owner-foo alias information into the envelope sender.
		Based on code from John Gardiner Myers.  This is a major
		semantic change -- beware!
	Allow $@ on LHS to indicate "match zero" -- this is used to match
		the null expression.

6.26/6.8	93/02/21
	Don't "lose" queue runs.  Very important fix from (who else?)
		Eric Wassenaar.
	Completely reset state on RSET command -- from Eric Wassenaar.
	Send error messages and return receipts using an envelope sender
		of <> regardless of the setting of $n.  Rewriting rules
		can undo this if they feel the necessity, as might be
		needed for networks that don't understand the syntax.
		This is permitted by RFC 821 section 3.6 and required by
		RFC 1123 section 5.3.3.  THIS REQUIRES VERSION 4 CONFIG
		FILES because the rulesets must be able to parse <>
		properly.
	Don't ever send error messages to "<>" -- they will get sent to
		the local postmaster or dumped in /usr/tmp/dead.letter
		instead.  Per RFC 1123 section 5.3.3.
	Explicitly check for email to yourself as a dotted quad.  You
		have to call $[ [ ... ] $] to get this.
	Up the message timeout to five days per RFC 1123 section 5.3.1.1.
	Make all read timeouts individually configurable, as strongly
		recommended by RFC 1123 section 5.3.2.
	Use f_bavail (blocks available to regular users) instead of f_bfree
		(blocks available to superuser) in free block checks.
	Change $d macro to be the current time, not the origination time,
		since this is consistent with how it is used now.
	Generalization of enoughspace from Eric Wassenaar covering
		SGI, Apollo, HPUX, Ultrix, and SunOS.
	Ignore process group signals -- some front ends can do this if
		you kill a window too quickly.  From Eric Wassenaar.
	Change umask to 022.

6.25/6.8	93/02/20
	Close all cached connections before calling mailers and after
		forking for delivery (caused double closes which resulted
		in false errors).
	Add FEATURE(redirect) in config files -- this allows you to alias
		old addresses to a pointer to the new address that will
		give a 551 error message, but not deliver the mail.
	Some code changes to make the 551 errors look pretty.
	Names of M4 program paths in config files have changed -- they
		are all XXX_MAILER_PATH now, to match XXX_MAILER_FLAGS.
	Fix a bug in the QSELFREF code having to do with empty .forward
		files, reported by Eric Wassenaar.
	Add option "p" (privacy flags); this allows you to tune how
		picky the SMTP server will be.  This also adds the
		confPRIVACY_FLAGS M4 macro in the config files.
	Add option "b" (minimum blocks free).  If there are fewer than
		this number of blocks free on the filesystem containing
		the queue directory, the SMTP MAIL command will return
		a 452 response and ask you to try again later.  This
		also adds the confMIN_FREE_BLOCKS M4 macro in the config
		files.
	Made VRFY just verify (doesn't expand aliases and .forward files);
		EXPN does full expansion.  RCPT in queue-only mode also
		doesn't chase aliases and .forward.

6.24/6.7	93/02/19
	Increase the number of domain search entries in domain.c to allow
		for the extra "" entry indicating the root domain.
		Reported by Motonori Nakamura of Kyoto U.
	Add a "SMART_HOST" in the configs for UUCP-connected sites that
		want to forward all mail with extra "@"s to that site.
		Also allows SMART_HOST, LOCAL_RELAY, and MAIL_HUB to
		be specified as ``mailer:hostname'' to use an alternate
		mailer.
	Clarified and updated some wording in the Operations Guide.
	Add the "c" mailer flag -- this suppresses all comment parts of
		addresses (requested by John Curran of NEARnet).
	Have -v print prompts in -bt mode even if stdin is not a terminal
		(default behaviour is to be silent if not reading from
		a terminal).  Suggested by Bryan Costales, ICSI.
	Move the metacharacters from C0 space (\001-\037) into C1 space
		(\201-\237).  This also fixes a bunch of potential bugs
		with G1 characters (\240-\276) in headers relating to
		negative numbers passed to isspace() et al.
	Add YP_LAST_MODIFIED and YP_MASTER_NAME to DBM version of alias
		database if YPCOMPAT is #defined.  Enhancement from
		Takahiro Kanbe of Fuji Xerox Information Systems Co., Ltd.
	Add "list" Precedence (-30); this can be used with old sendmails
		which will map to precedence 0 (which will return error
		messages).  Suggested by Stephen R. van den Berg.
	Many bug fixes from Eric Wassenaar of the National Institute for
			Nuclear and High-Energy Physics, Amsterdam:
		Clear timeouts properly on open failures in include().
		Don't dereference through NULL if no home directory found.
		Re-establish SIGCHLD signal on System 5 in reapchild().
		Avoid NULL pointer reference on -pFOO flag.
		Properly handle backslash escapes in comments.
		Correctly check reply status on SMTP NOOP command.
		Properly save SMTP error message if peer gives
			"Service Shutting Down" message.
		Avoid writing to the transcript if it couldn't be opened.
		Signal errors in SMTP children to parent properly.
	Handle self references in a list more globally (include a
		QSELFREF bit in the address flags).  This enhancement
		was suggested by Eric Wassenaar.
	Use initgroups() in hpux, even though it's System-V based.  The
		HASINITGROUPS compile flag can set this on other systems.
		This HPUX behaviour was pointed out by Eric Wassenaar.

6.23/6.6	93/02/16
	Clean up handling of LogLevel to make it easier to figure out
		what's on what level.
	Change log levels to have some consistency:
		1    serious system failures, security problems
		2    lost communications, protocol failures
		3    other serious failures
		4    minor errors
		5    message collection
		6    vrfy logging, creation of return-to-sender
		7    delivery failures
		8    delivery successes
		9    delivery tempfails (queue ups)
		10   database expansion
		>64  debugging
	Allow IDA-style separated processing on S= and R= in Mailer
		definition lines.  Note that rulesets 1 and 2 are
		still used for both addresses as before.  Bruce Lilly
		gave a convincing argument that RFC976 insists on
		this behaviour.
	Added some time zones to arpatounix -- they may not be in the
		standards, but they are in use.  However, I may delete
		arpatounix entirely -- there appears to be no reason
		for it to exist.
	Change to UUCP mailer (in cf directory) to try to do a saner job.
		I'm still not certain about this mailer in general.

6.22/6.5	93/02/15
	Fix bug that prevents saving letters in ~/dead.letter.
	Don't add angle brackets in VRFY command if angle brackets already
		exist in the address.
	Fix bogus error message in udbexpand.
	Null terminate host buffers in buildaddr (broken in 6.21) --
		IMPORTANT FIX!!

6.21/6.5	93/02/15
	Fix another incorrect error message in alias.c, found by Azuma
		Okamoto.
	Fix a couple of problems in the more-configurable config files,
		found by Tom Ivar Helbekkmo.
	Fix problem with quoted :include: entries.
	Don't duplicate the filename on verbose printing of .forward and
		:include: contents.
	Extend size of prescan buffer (to allow bigger addresses).  Also,
		detect some buffer overflows.
	Log user SMTP protocol errors (log level 4).

6.20/6.4	93/02/14
	Fix another problem in the MCI state machine caused when there
		were errors generated from the other end to commands
		other than RCPT.

6.19/6.4	93/02/14
	Include load average support for DEC Alpha running OSF/1.
	Fix multiple-response problem with errors in MAIL From: line.
	Fix SMTP reply codes for invalid address syntaxes (give 501;
		never give multiple error messages for a single message).
	Fix problem where a cached connection timeout rejects all
		later connects to that host.
	Fix incorrect error message if alias.c is compiled with DBM only.
	Additional changes to fix nested conditionals (from Bruce Lilly).
	Recover more gracefully from operating system failures, particularly
		NULL returns from openmailer (from Noritoshi Demizu,
		OMRON Corporation).
	Log forward, alias, and userdb expand operations on log level 10;
		concept suggested by P{r (Pell) Emanuelsson.
	Changes for HPUX 8.07 compatibility.

6.18/6.4	93/02/12
	Allow any config option to be set using an M4 define.
	Change UNAME compile flag to HASUNAME for IDA compatibility
		(besides, it's a better name).
	Note in README that on SunOS it must be linked -Bstatic.
	Fairly major change in domain.c to handle wildcard MX records
		more rationally.  NOTE: the "w" option (no wildcard MX
		records match local domain) has been eliminated.
	Fix some unset variable references pointed out by Bruce Lilly.
	Fix host name in process titles when using cached connection.

6.17/6.3	93/01/28
	Fix System 5 compatibility changes to be compatible with the rest
		of the world.

6.16/6.3	93/01/28
	Experimental fix for problem handling errors in the SMTP
		protocol in conjunction with connection caching.
	System 5 compatibility changes.

6.15/6.3	93/01/26
	Fix a bug that causes local mail delivered using -odq to be
		eliminated as a duplicate (because it matched the
		ctladdr, now passed in as a C line).  These changes
		are pretty tricky......

6.14/6.3	93/01/25
	Add debugging for some MCI errors.

6.13/6.3	93/01/22
	Fix -e compatibility flag to take a value.
	Fix a couple of minor compilation warnings on Sun cc.
	Improve error messages in a few cases to be more self-explanatory.

6.12/6.3	93/01/21
	Fix yet-another problem with environment handling, pointed out
		by Yoshitaka Tokugawa and Tom Ivar Helbekkmo.
	Some heuristics to try to limit resource exhaustion problems
		if a downstream host has been down for a long time.
	Fix problem with incorrect host name being logged in "Connection
		timed out" messages (from Tom Ivar Helbekkmo).
	Fix some ANSI C problems (from Takahiro Kanbe).
	Properly log message sender on returned mail during queue run.
	Count number of recipients properly.
	Fix a problem in yp map code.
	Diagnose "message timed out" (from Motonori Nakamura).

6.11/6.3	93/01/20
	Fix problem with address delimitor inside quotes.
	Define $k and $=k to be the UUCP name (from the uname call)
		based on code from Bruce Lilly.

6.10/6.2	93/01/18
	Implement arpatounix (largely code from Bruce Lilly).
	Log more info (suggested by John Myers).
	Allow nested $?...$|...$. (inspired by code from Bruce Lilly of
		Sony US).
	POSIX compatibility (noted by Keith Bostic).
	Handle SMTP MAIL command errors properly (urged by several people,
		notably John Myers of CMU).
	Do early diagnosis of .cf errors (notably referencing a RHS
		substitution that isn't on the LHS).
	Adjust checkpointing to better handle batched recipients, suggested
		by John Myers.
	Fix miscellaneous bugs.
	(config files:)  Implement MAIL_HUB for all local mail (to handle
		NFS-mounted directories) as urged by Tom Ivar Helbekkmo
		of the Norwegian School of Economics.

6.9/6.1 	93/01/13
	Environment handling simplification/bug fix -- child processes
		get a minimal, fixed environment.  This avoids different
		behaviour in queue runs.
	Handle commas inside comments properly.
	Properly limit large messages submitted in -obq mode.

6.8/6.1		93/01/10
	Check mtime of thaw file against .cf and sendmail binary, based on
		code from John Myers.

6.7/6.1		93/01/10
	MX piggybacking, based on code from John Myers@CMU.
	Allow checkcompat to return -1 to mean tempfail.
	Bug fix in m_mno computation.

6.6/6.1		93/01/09
	Tuning of queueing functions as recommended by John Gardiner Myers.
	Return mail headers (no body) on messages with negative precedence.
	Minor other bug fixes.

6.5/6.1		93/01/03
	Fix botch causing queued headers to have ?XX? prefixes.

6.4/6.1		93/01/02
	Changes to recognize special mailer types (e.g., file) early.

6.3/6.1		93/01/01
	Pass timeouts to sfgets.
	Check for control characters in addresses.
	Fixed deferred error reporting.
	Report duplicate aliases.
	Handle mixed case recursive aliases.
	Misc bug fixes.

6.2/6.1		92/12/30
	Put return-receipt-to on a conf.c flag (but don't set it).
	Fix minor syslog problem.