1 $Cambridge: exim/doc/doc-txt/Exim3.upgrade,v 1.1 2004/10/07 15:04:35 ph10 Exp $
3 This document contains information about upgrading Exim to the last of the 3.xx
4 releases. It is provided to help anybody who is upgrading to release 4.xx from
5 a release that is earlier than 3.33. It goes back as far as release 2.12. If
6 you are upgrading to release 4.xx from an even earlier release, it is probably
7 best to start again from the default configuration.
10 Upgrading from release 3.16
11 ---------------------------
13 1. The way LDAP returns values for multiple attributes has been changed to be
14 the same as the NIS+ lookup.
16 If you specify multiple attributes, they are returned as space-separated
17 strings, quoted if necessary.
19 e.g. ldap:///o=base?attr1,attr2?sub?(uid=fred)
21 used to give: attr1=value one, attr2=value2
22 now gives: attr1="value one" attr2=value2
24 If you don't specify any attributes in the search, you now get them in
25 the tagged format as well.
27 e.g. ldap:///o=base??sub?(uid=fred)
29 used to give: top, value one, value2
30 now gives: objectClass=top attr1="value one" attr2=value2
32 The reason for these changes is so that the results can be safely parsed -
33 in fact, the existing ${extract{key}{val}} function does this nicely.
34 This in turn allows a single LDAP query to be reused - one query can return
35 the destination delivery address, the quota, and so forth.
37 This is NOT a backwards compatible change, so there is a compile-time option
38 to reverse it in the src/lookups/ldap.c module, for use in emergency. But it is
39 not thought that the old behaviour was particularly useful as it stood, because
40 a field that contained ',' or '=' would make the result unparseable.
42 In the common case where you explicitly ask for a single attribute in your
43 LDAP query, the behaviour is unchanged - the result is not quoted, and if there
44 are multiple values they are comma-separated.
46 2. The hosts_max_try option in the smtp transport limits the number of IP
47 addresses that will actually be tried during one delivery attempt. The default
48 is 5. Previously, all available addresses were tried.
50 3. The extension of the "extract" expansion item has resulted in a change to
51 the way Exim decides between the keyed form and the numeric form. If the first
52 argument consists entirely of digits, the numeric form is assumed. This means
53 that it is impossible to have keys that are digit strings, without manipulating
54 the data first (e.g. by using ${sg} to add a letter to each key).
57 Upgrading from release 3.15
58 ---------------------------
60 1. The handling of "freeze" and "fail" in system filter files has changed.
61 Previously, any deliveries set up by a filter that ended with "freeze" or
62 "fail" were discarded. This no longer happens; such deliveries are honoured.
63 A consequence of this is that first_delivery becomes false after freezing in a
64 system filter; previously it remained true until a real delivery attempt
68 Upgrading from release 3.13
69 ---------------------------
71 1. The handling of maildir_tag has been changed (see NewStuff). There are two
72 small incompatibilities: (a) Exim now inserts a leading colon only if the
73 string begins with an alphanumeric character. So if you were using a string
74 starting with a special character, you will have to add the leading colon to
75 it to remain compatible. (b) The expansion of maildir_tag now happens after the
76 file has been written, and $message_size is updated to the correct file size
77 before the expansion. The tag is not used on the temporary file (it was
80 2. The handling of Exim's configuration has changed in two ways:
82 (a) Any line may be continued by ending it with a backslash. Trailing white
83 space after the backslash, and leading white space on continuation lines is
84 ignored. This means that quotes are no longer needed just to make it possible
85 to continue an option setting. The difference between quoted and non-quoted
86 strings is that quoted strings are processed for internal backslashed items
87 such as \n. The only possible incompatibility of this change is if any
88 existing configuration has a non-quoted line ended in backslash, which seems
89 a very remote possibility.
91 (b) All lists, with the exception of log_file_path, can now use a different
92 character to colon as the separator. This is specified by starting the list
93 with <x where x is any punctuation character. For example:
95 local_interfaces = <; 127.0.0.1 ; ::1
97 The new feature is provided to make life easier with IPv6 addresses. It is
98 recommended that its use be confined to circumstances where it really is
99 needed, and that colon be used in most cases. I don't believe this change
100 is incompatible, because I don't think any list item can legitimately begin
101 with a '<' character.
103 3. Previously, Exim took no action to ensure that the timestamps in its log
104 files were "wall clock time". If the TZ environment variable was set when Exim
105 was called, it could cause strange times to be logged. For the majority of
106 operating systems, I have been able to fix this problem by deleting the entire
107 environment. However, this doesn't work in some systems, and a macro called
108 HANDS_OFF_ENVIRONMENT is defined in their OS/os.h files to suppress the action.
109 These OS are: AIX, DGUX, HP-UX, IRIX, and SCO, and their behaviour should be
110 unchanged from previous releases. On any other OS, if you find you are getting
111 weird timestamps, it may be that your OS needs HANDS_OFF_ENVIRONMENT.
113 4. As a result of the change described in 3, there may be some cases where Exim
114 runs an external program that previously got passed the environment, and now do
115 not. This does *not* apply to the pipe transport, where the environment has
116 always been set up specifically, as described in the manual.
118 5. The way in which Exim scans its queue when split_spool_directory is set has
119 changed, but this shouldn't make any noticeable difference. See doc/NewStuff
123 Upgrading from release 3.03
124 ---------------------------
126 The from_hack option in the appendfile and pipe transports has been replace by
127 two string options, check_string and escape_string. If your configuration
128 contains any references to from_hack they should be replaced. Exim continues to
129 recognize from_hack as a transitional measure. If no_from_hack is specified in
130 an appendfile transport, the two new options are forced to be unset. Otherwise
131 the setting of from_hack is ignored.
134 Upgrading from release 3.02
135 ---------------------------
137 The exim_dbmbuild utility has been changed to write a warning to stderr on
138 encountering a duplicate key, and to return a value of 1. Formerly, it ignored
139 all but the last of a set of duplicates; now it ignores all but the first, to
140 make dbm-searched files behave the same way as lsearch-searched files. However,
141 there is an option -lastdup which makes it behave as before. The -nowarn option
142 suppresses the individual warnings, but the number of duplicates is always
143 listed on stdout at the end.
146 Updating from a release prior to 3.00
147 -------------------------------------
149 Prior to release 3.00 a lot of options which contained lists of various kinds
150 came in groups such as sender_accept, sender_reject, sender_reject_except. This
151 style of configuration has been abolished. Instead, it is now possible to put
152 negative entries in such lists, so that a single option is all that is
153 required. In addition to this, net lists have been abolished, and instead,
154 host lists can now contain items that specify networks as well as hosts. The
155 names of some of these options have also been changed.
157 As a result of these changes, most configuration files used for earlier
158 versions of Exim need to be changed. The opportunity has therefore been taken
159 to remove a number of other obsolete features and options.
161 A Perl script is built in the file util/convert4r3 to assist in updating Exim
162 configuration files. It reads a configuration file on the standard input,
163 writes a modified file on the standard output, and writes comments about what
164 it has done to the standard error file. It assumes that the input is a valid
165 Exim configuration file. A typical call to the conversion script might be
167 util/convert4r3 </opt/exim/configure >/opt/exim/configure.new
169 The way the script merges an accept/reject/reject_except triple into a single
170 accept option is to put the reject_except list first, followed by the reject
171 list with every item negated, followed by the accept list. For example, if an
172 old configuration file contains
174 sender_host_accept_relay = *.c.d : e.f.g
175 sender_host_reject_relay = *.b.c.d
176 sender_host_reject_relay_except = a.b.c.d
178 the new configuration will contain
180 host_accept_relay = a.b.c.d : ! *.b.c.d : *.c.d : e.f.g
182 The same ordering is used to merge a triple into a reject option, but this time
183 the first and third sublists are negated. For example, if an old configuration
186 sender_host_accept = *.c.d : e.f.g
187 sender_host_reject = *.b.c.d
188 sender_host_reject_except = a.b.c.d
190 the new configuration file will contain
192 host_reject = ! a.b.c.d : *.b.c.d : ! *.c.d : ! e.f.g : *
194 The output file should be checked before trying to use it. Each option change
195 is preceded by an identifying comment. There are several specific things that
196 you should look out for when checking:
198 (1) If you are using macros to contain lists of items, and these have to be
199 negated in the new world, convert4r3 won't get it right. For example, if
200 the old configuration contains
202 ACCEPTHOSTS = *.c.d : e.f.g
203 sender_host_reject = ACCEPTHOSTS
205 then the rewritten configuration will be
207 ACCEPTHOSTS = *.c.d : e.f.g
208 host_reject = !ACCEPTHOSTS
210 but because this is just textual macro handling, that is equivalent to
212 host_reject = !*.c.d : e.f.g
214 which is not the correct translation, because the second item is not
215 negated. There is unfortunately no easy way to use a macro to provide a
216 list of things that are sometimes negated.
218 (2) The conversion adds some settings of file_transport, pipe_transport, and
219 reply_transport to aliasfile and forwardfile directors. This is done
220 because the global implicit defaults for these options have been removed.
221 The default configuration now contains explicit settings, so convert4r3
222 makes these additions to be compatible with that. If your aliasfile and
223 forwardfile directors do not make use of the pipe, file, or autoreply
224 facilities, you can remove these new settings.
226 (3) If you are using +allow_unknown in a host list which also has an exception
227 list, you may need to move +allow_unknown in the new configuration. For
228 example, if the old configuration contains
230 sender_host_reject = +allow_unknown : *.b.c
231 sender_host_reject_except = *.a.b.c
233 then the rewritten configuration will be
235 host_reject = ! *.a.b.c : +allow_unknown : *.b.c
237 Because the negated item contains a wild card, the reverse lookup for the
238 host name will occur before +allow_unknown is encountered, and therefore
239 +allow_unknown will have no effect. It should be moved to the start of the
242 One way of upgrading Exim from a pre-3.00 release to a post-3.00 release is as
245 1. Suppose your configuration file is called /opt/exim/configure, and you want
246 to continue with this name after upgrading. The first thing to do is to make
247 another copy of this file called, say, /opt/exim/configure.pre-3.00.
249 2. Rebuild your existing Exim to use the copy of the configuration file instead
250 of the standard file. Install this version of Exim under a special name such
251 as exim-2.12, and point a symbolic link called "exim" at it. Then HUP your
252 daemon. You can check on the name of the configuration file by running
254 exim -bP configure_file
256 Ensure that everything is running smoothly.
258 3. Build the new release, configured to use the standard configuration file.
260 4. Use the convert4r3 utility to upgrade your configuration file for the new
261 release. After running it, check the file by hand.
263 5. If any of the options that convert4r3 rewrote contained regular expressions
264 that had backslashes in them, and were not previously in quotes, they will
265 need modification if convert4r3 has put them into quotes. Either re-arrange
266 the option to remove the quoting, or escape each backslash. For example, if
269 sender_reject_recipients = ^\d{8}@
270 sender_reject_except = ^\d{8}@x.y.z
272 convert4r3 will have combined the two settings into
274 sender_reject_recipients = "! ^\d{8}@x.y.z : \
277 This must be changed to
279 sender_reject_recipients = ! ^\d{8}@x.y.z : ^\d{8}@
281 sender_reject_recipients = "! ^\\d{8}@x.y.z : ^\\d{8}@"
283 In the second case, the quoted string could of course still be split
286 6. If your configuration refers to any external lists of networks, check them
287 to ensure that all the masks are in the single-number form, because Exim no
288 longer recognizes the dotted quad form of mask. For example, if an item in
291 131.111.8.0/255.255.255.0
293 you must change it to
297 Otherwise Exim will not recognize it as a masked IP address, and will treat
298 it as a host name. The convert4r3 utility makes this conversion for networks
299 that are mentioned inline in the configuration, but it does not handle
302 7. Check the newly-built Exim as much as possible without installing; you can,
303 for example, use a command such as
307 in the build directory to test that it successfully reads the new
308 configuration file. You can also do tests using -bt and -bh.
310 8. Install the new release under a special name such as exim-3.00.
312 9. You can then easily change between the new and old releases simply by moving
313 the symbolic link and HUPping your daemon.
316 Details of syntax changes at 3.00
317 =================================
319 1. A bare file name without a preceding search type may appear in a domain
320 list; this causes each line of the file to be read and processed as if it were
321 an item in the list, except that it cannot itself be a bare file name (that is,
322 this facility cannot be used recursively). Wild cards and regular expressions
323 may be used in the lines of the file just as in the main list.
326 local_domains = /etc/local-domains
328 then the file could contain lines like
332 This is different to an lsearch file, which operates like any other lookup type
333 and does an exact search for the key. If a # character appears anywhere in a
334 line of the file, it and all following characters are ignored. Blank lines are
337 2. Any item in a domain list (including a bare file name) can be preceded by an
338 exclamation mark character, to indicate negation. White space after the ! is
339 ignored. If the domain matches the rest of the item, it is *not* in the set of
340 domains that the option is defining. If the end of the list is reached, the
341 domain is accepted if the last item was a negative one, but not if it was a
342 positive one. If ! precedes a bare file name, then all items in the file are
343 negated, unless they are preceded by another exclamation mark. For example:
345 relay_domains = !a.b.c : *.b.c
347 sets up a.b.c as an exception to the more general item *.b.c, because lists are
348 processed from left to right. If the domain that is being checked matches
349 neither a.b.c nor *.b.c, then it is not accepted as a relay domain, because the
350 last item in the list is a positive item. However, if the option were just
352 relay_domains = !a.b.c
354 then all domains other than a.b.c would be relay domains, because the last item
355 in the list is a negative item. In effect, a list that ends with a negative
356 item has ": *" appended to it.
358 3. Negation and bare file names are available as above in lists of local parts
359 (e.g. in local_parts options) and complete addresses (address lists). For the
360 special "@@" lookup form in address lists, negation also can be used in the
361 list of local parts that is looked up for the domain. For example, with
363 sender_reject_recipients = @@dbm;/etc/reject-by-domain
365 the file could contain lines like this:
367 baddomain.com: !postmaster : !hostmaster : *
369 If a local part that actually begins with ! is required, it has to be specified
370 using a regular expression. Because local parts may legitimately contain #
371 characters, a comment in the file is recognized only if # is followed by white
372 space or the end of the line.
374 4. Host lists may now contain network items, as in the former net list options,
375 which have all been abolished. The only form of network masking is the /n
376 variety. Negation and bare file names can appear in host lists, and there is a
377 new type of item which allows masked network numbers to be used as keys in
378 lookups, thus making it possible to used DBM files for faster checking when the
379 list of networks is large.
381 The complete list of types of item which can now appear in a host list is:
383 . An item may be a bare file name; each line of the file may take the form of
384 any of the items below, but it may not itself be another bare file name. If
385 the file name is preceded by ! then all items in the file are negated, unless
386 they are preceded by another exclamation mark. Comments in the file are
387 introduced by # and blank lines are ignored.
389 . If the entire item is "*" it matches any host.
391 . If the item is in the form of an IP address, it is matched against the IP
392 address of the incoming call.
394 . If the item is in the form of an IP address followed by a slash and a mask
395 length (e.g. 131.111.0.0/16) then it is matched against the IP address of the
396 incoming call, subject to the mask.
398 . If the item is of the form "net<number>-<search-type>;<search-data>", for
401 net24-dbm;/networks.db
403 then the IP address of the incoming call is masked using <number> as the mask
404 length; a textual string is then constructed from the masked value, followed
405 by the mask, and this is then used as the key for the lookup. For example, if
406 the incoming IP address is 192.152.34.6 then the key that is looked up for
407 the above example is "192.152.34.0/24".
409 . If the entire item is "@" the primary host name is used as the the match
410 item, and the following applies:
412 . If the item is a plain domain name, then a forward DNS lookup is done on that
413 name to find its IP address(es), and the result is compared with the IP
414 address of the incoming call.
416 The remaining items require the host name to be obtained by a reverse DNS
417 lookup. If the lookup fails, Exim takes a hard line by default and access is
418 not permitted. If the list is an "accept" list, Exim behaves as if the current
419 host is not in the set defined by the list, whereas if it is a "reject" list,
420 it behaves as if it is.
422 To change this behaviour, the special item "+allow_unknown" may appear in the
423 list (at top level - it is not recognized in an indirected file); if any
424 subsequent items require a host name, and the reverse DNS lookup fails, Exim
425 permits the access, that is, its behaviour is the opposite to the default.
427 . If the item starts with "*" then the remainder of the item must match the end
428 of the host name. For example, *.b.c matches all hosts whose names end in
429 .b.c. This special simple form is provided because this is a very common
430 requirement. Other kinds of wildcarding require the use of a regular
433 . If the item starts with "^" then it is taken to be a regular expression which
434 is matched against the host name. For example, ^(a|b)\.c\.d$ matches either
435 of the two hosts a.c.d or b.c.d. If the option string in which this occurs is
436 given in quotes, then the backslash characters must be doubled, because they
437 are significant in quoted strings. The following two settings are exactly
440 host_accept = ^(a|b)\.c\.d$
441 host_accept = "^(a|b)\\.c\\.d$"
443 . If the item is of the form <search-type>;<filename or query>, for example
445 dbm;/host/accept/list
447 then the host name is looked up using the search type and file name or query
448 (as appropriate). The actual data that is looked up is not used.
450 5. Early versions of Exim required commas and semicolons to terminate option
451 settings in drivers. This hasn't been the case for quite some time. The code to
452 handle them has now been removed.
455 Details of option changes at 3.00
456 =================================
461 * address_directory_transport, address_directory2_transport,
462 address_file_transport, address_pipe_transport, and address_reply_transport
463 have been abolished as obsolete. The aliasfile and forwardfile directors
464 have been able for some time to set the transports they want to use for
465 these special kinds of delivery; there seems little need for global
466 defaults. The default configuration has been altered to add settings for
467 file_transport and pipe_transport to the aliasfile and forwardfile
468 directors, and to add reply_transport to forwardfile.
470 * check_dns_names, a deprecated synonym for dns_check_names, has been
473 * helo_accept_junk_nets is abolished; nets can now appear in
474 helo_accept_junk_hosts.
476 * helo_verify_except_hosts and helo_verify_except_nets have been abolished,
477 and helo_verify has been changed from a boolean to a host list, listing
478 those hosts for which HELO verification is required.
480 * the obsolete option helo_verify_nets (a synonym for host_lookup_nets) has
481 been abolished. Note that host_lookup_nets itself has been replaced by
484 * hold_domains_except has been abolished. Use negated items in hold_domains.
486 * host_lookup_nets has been replaced by host_lookup, which can contain hosts
489 * ignore_fromline_nets has been replaced by ignore_fromline_hosts.
491 * If message_filter is set and the filter generates any deliveries to files,
492 pipes, or any autoreplies, then the appropriate message_filter_*_transport
493 options must be set to define the transports, following the abolition of
494 the global defaults (see above).
496 * queue_remote and queue_remote_except have been abolished and replaced by
497 queue_remote_domains, which lists those domains that should be queued. The
498 effect of queue_remote=true is now obtained by queue_remote_domains=*.
500 * queue_smtp and queue_smtp_except have been abolished and replaced by
501 queue_smtp_domains, which lists those domains that should be queued after
502 routing. The effect of queue_smtp=true is now obtained by
503 queue_smtp_domains=*.
505 * rbl_except_nets has been abolished and replaced by rbl_hosts, which can
506 contain hosts and nets. This defaults to "*" and defines the set of hosts
507 for which RBL checking is done.
509 * receiver_unqualified_nets is abolished; nets can now appear in
510 receiver_unqualified_hosts.
512 * receiver_verify_except_hosts and receiver_verify_except_nets have been
513 abolished and replaced by receiver_verify_hosts, which defaults to "*".
514 This is used, however, only when receiver_verify is set - together with the
515 other conditions (receiver_verify_addresses, receiver_verify_senders).
517 * receiver_verify_senders_except has been abolished; the functionality is now
518 available by using negation in receiver_verify_senders.
520 * rfc1413_except_hosts and rfc1413_except_nets have been abolished, and
521 replaced by rfc1413_hosts, which defaults to "*".
523 * sender_accept, sender_accept_recipients and sender_reject_except have
524 been abolished; the functionality is now available via sender_reject and
525 sender_reject_recipients.
527 * sender_host_accept, sender_net_accept, sender_host_reject,
528 sender_net_reject, sender_host_reject_except, sender_net_reject_except,
529 sender_host_reject_recipients and sender_net_reject_recipients
530 have all been abolished, and replaced by the options host_reject and
531 host_reject_recipients.
533 * sender_host_accept_relay, sender_net_accept_relay,
534 sender_host_reject_relay, sender_host_reject_relay_except,
535 sender_net_reject_relay, and sender_net_reject_relay_except are abolished,
536 and replaced by host_accept_relay. This defaults unset, and this means that
537 all relaying is now by default locked out in the Exim binary. Previously,
538 if no relaying options were set, relaying was permitted.
540 * sender_unqualified_nets has been abolished; nets can now appear in
541 sender_unqualified_hosts.
543 * sender_verify_except_hosts and sender_verify_except_nets have been
544 abolished and replaced by sender_verify_hosts, which defaults to "*". This
545 is used, however, only when sender_verify is set (to make it similar to
546 receiver_verify, even though there aren't at present any other conditions.)
548 * sender_verify_log_details has been abolished. This was a little-used
551 * smtp_etrn_nets has been abolished; nets can now appear in smtp_etrn_hosts.
553 * smtp_expn_nets has been abolished; nets can now appear in smtp_expn_hosts.
555 * smtp_log_connections, a deprecated synonym for log_smtp_connections, has
558 * smtp_reserve_nets is abolished; nets can now appear in smtp_reserve_hosts.
560 Generic director and router options
561 -----------------------------------
563 * except_domains, except_local_parts, and except_senders have been abolished.
564 Use negated items in domains, local_parts, and senders instead, for
567 except_domains = a.b.c
573 If you already have a domains setting, add any negative items to the front
576 The aliasfile director
577 ----------------------
579 * The option "directory", an obsolete synonym for home_directory, has been
582 The forwardfile director
583 ------------------------
585 * The option "directory", an obsolete synonym for file_directory, has been
588 * The option forbid_filter_log, an obsolete synonym for
589 forbid_filter_logwrite, has been abolished.
591 The localuser director
592 ----------------------
594 * The option "directory", an obsolete synonym for match_directory, has been
597 The lookuphost router
598 ---------------------
600 * mx_domains_except and its obsolete old name non_mx_domains have been
601 abolished. Use negated items in mx_domains.
606 * The option "directory", an obsolete synonym for home_directory, has been
612 * mx_domains_except and its obsolete old name non_mx_domains have been
613 abolished. Use negated items in mx_domains.
615 * serialize_nets has been abolished; nets may now appear in serialize_hosts.
618 Other items relevant to upgrading from Exim 2.12
619 ================================================
621 1. RFC 2505 (Anti-Spam Recommendations for SMTP MTAs) recommends that the
622 checking of addresses for spam blocks should be done entirely caselessly.
623 Previously, although Exim retained the case of the local part, in accordance
624 with the RFC 821 rule that local parts are case sensitive, some of the string
625 comparisons were nevertheless done caselessly, but file lookups used the
628 The way addresses are compared with options whose values are address lists has
629 been changed. At the start of the comparison, both the local part and the
630 domain are now forced to lower case, and any comparisons that are done with
631 in-line strings are done caselessly. For example,
633 sender_reject = A@b.c
635 rejects both A@b.c and a@b.c. Any lookups that occur use lowercased strings as
636 their keys. If the @@ lookup facility is used, the lookup is done on the lower
637 cased domain name, but any subsequent string comparisons on local parts are
640 To retain possibility of caseful matching, the pseudo-item "+caseful" can
641 appear in an address list. It causes any subsequent items to do caseful matches
642 on local parts. The domain, however, remains lower cased.
644 2. The handling of incoming batched SMTP has been re-worked so as to behave in
645 a more useful way in cases of error:
647 (i) The option sender_verify_batch now defaults false.
648 (ii) EOF is no longer interpreted as end-of-message; the "." line must be
650 (iii) Exim stops immediately in cases of error, writing information to stdout
651 and stderr, and setting the return code to 1 if some messages have been
652 accepted, and 2 otherwise.
654 3. The first message delivered by -R, and all messages delivered by -Rf and -qf
655 are "forced" in the sense that retry information is over-ridden. Previously,
656 Exim also forcibly thawed any of these messages that was frozen. This no longer
657 happens. Additional options -Rff and -qff have been implemented to force
658 thawing as well as delivery.
660 4. When recipients are being rejected because the sending host is in an RBL
661 list, Exim used just to show the RBL text, if any, as part of the rejection
662 response. Now, if prohibition_message is set, it expands that string instead,
663 with the RBL message available in $rbl_text, and $prohibition_reason set to
666 5. When a trusted caller passed a message to Exim, it used to check the From:
667 header against the caller's login (even though the caller was trusted) unless
668 the -f option had been used to supply a different sender. This has been changed
669 so that From: is never checked if the caller is trusted.