Merge branch 'master' of ssh://git.exim.org/home/git/exim

[users/heiko/exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index ad4df88ea8abf3b6124bedff74fdb98bc7a88090..31767bf5552e1c36857d8fd39938f068b7f3672c 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -179,12 +179,7 @@
 <author><firstname>Exim</firstname><surname>Maintainers</surname></author>
 <authorinitials>EM</authorinitials>
 <revhistory><revision>
 <author><firstname>Exim</firstname><surname>Maintainers</surname></author>
 <authorinitials>EM</authorinitials>
 <revhistory><revision>

-  <revnumber>
-.version
-  </revnumber>
-  <date>
-.fulldate
-  </date>
+.versiondatexml

   <authorinitials>EM</authorinitials>
 </revision></revhistory>
 <copyright><year>
   <authorinitials>EM</authorinitials>
 </revision></revhistory>
 <copyright><year>


@@ -8268,10 +8263,13 @@ apply to temporary DNS errors, whose handling is described in the next section.
 
 .cindex "&`+include_unknown`&"
 .cindex "&`+ignore_unknown`&"
 
 .cindex "&`+include_unknown`&"
 .cindex "&`+ignore_unknown`&"

-By default, Exim behaves as if the host does not match the list. This may not
-always be what you want to happen. To change Exim's behaviour, the special
-items &`+include_unknown`& or &`+ignore_unknown`& may appear in the list (at
-top level &-- they are not recognized in an indirected file).
+Exim parses a host list from left to right. If it encounters a permanent
+lookup failure in any item in the host list before it has found a match,
+Exim treats it as a failure and the default behavior is as if the host
+does not match the list. This may not always be what you want to happen.
+To change Exim's behaviour, the special items &`+include_unknown`& or
+&`+ignore_unknown`& may appear in the list (at top level &-- they are
+not recognized in an indirected file).

 
 .ilist
 If any item that follows &`+include_unknown`& requires information that
 
 .ilist
 If any item that follows &`+include_unknown`& requires information that


@@ -8299,6 +8297,37 @@ Both &`+include_unknown`& and &`+ignore_unknown`& may appear in the same
 list. The effect of each one lasts until the next, or until the end of the
 list.
 
 list. The effect of each one lasts until the next, or until the end of the
 list.
 

+To explain the host/ip processing logic a different way for the same ACL:
+
+.ilist
+If you have name lookups or wildcarded host names and
+IP addresses in the same host list, you should normally put the IP
+addresses first. For example, in an ACL you could have:
+.code
+accept hosts = 10.9.8.7 : *.friend.example
+.endd
+The reason you normally would order it this way lies in the
+left-to-right way that Exim processes lists.  It can test IP addresses
+without doing any DNS lookups, but when it reaches an item that requires
+a host name, it fails if it cannot find a host name to compare with the
+pattern. If the above list is given in the opposite order, the
+&%accept%& statement fails for a host whose name cannot be found, even
+if its IP address is 10.9.8.7.
+
+.next
+If you really do want to do the name check first, and still recognize the IP
+address, you can rewrite the ACL like this:
+.code
+accept hosts = *.friend.example
+accept hosts = 10.9.8.7
+.endd
+If the first &%accept%& fails, Exim goes on to try the second one. See chapter
+&<<CHAPACL>>& for details of ACLs. Alternatively, you can use
+&`+ignore_unknown`&, which was discussed in depth in the first example in
+this section.
+.endlist
+
+

 
 .section "Temporary DNS errors when looking up host information" &&&
          "SECTtemdnserr"
 
 .section "Temporary DNS errors when looking up host information" &&&
          "SECTtemdnserr"


@@ -10882,6 +10911,16 @@ the value of &$authenticated_id$& is normally the login name of the calling
 process. However, a trusted user can override this by means of the &%-oMai%&
 command line option.
 
 process. However, a trusted user can override this by means of the &%-oMai%&
 command line option.
 

+.vitem &$authenticated_fail_id$&
+.cindex "authentication" "fail" "id"
+.vindex "&$authenticated_fail_id$&"
+When an authentication attempt fails, the variable &$authenticated_fail_id$&
+will contain the failed authentication id. If more than one authentication
+id is attempted, it will contain only the last one. The variable is
+available for processing in the ACL's, generally the quit or notquit ACL.
+A message to a local recipient could still be accepted without requiring
+authentication, which means this variable could also be visible in all of
+the ACL's as well.

 
 
 
 
 
 


@@ -15337,6 +15376,13 @@ live with.
 
 . Allow this long option name to split; give it unsplit as a fifth argument
 . for the automatic .oindex that is generated by .option.
 
 . Allow this long option name to split; give it unsplit as a fifth argument
 . for the automatic .oindex that is generated by .option.

+. We insert " &~&~" which is both pretty nasty visually and results in
+. non-searchable text.  HowItWorks.txt mentions an option for inserting
+. zero-width-space, which would be nicer visually and results in (at least)
+. html that Firefox will split on when it's forced to reflow (rather than
+. inserting a horizontal scrollbar).  However, the text is still not
+. searchable.  NM changed this occurrence for bug 1197 to no longer allow
+. the option name to split.

 
 .option "smtp_accept_max_per_connection" main integer 1000 &&&
          smtp_accept_max_per_connection
 
 .option "smtp_accept_max_per_connection" main integer 1000 &&&
          smtp_accept_max_per_connection


@@ -15388,10 +15434,9 @@ also &%queue_only%&, &%queue_only_load%&, &%queue_smtp_domains%&, and the
 various &%-od%&&'x'& command line options.
 
 
 various &%-od%&&'x'& command line options.
 
 

-. Allow this long option name to split; give it unsplit as a fifth argument
-. for the automatic .oindex that is generated by .option.
+. See the comment on smtp_accept_max_per_connection

 
 

-.option "smtp_accept_queue_per_ &~&~connection" main integer 10 &&&
+.option "smtp_accept_queue_per_connection" main integer 10 &&&

          smtp_accept_queue_per_connection
 .cindex "queueing incoming messages"
 .cindex "message" "queueing by message count"
          smtp_accept_queue_per_connection
 .cindex "queueing incoming messages"
 .cindex "message" "queueing by message count"


@@ -16031,6 +16076,21 @@ The available primes are:
 Some of these will be too small to be accepted by clients.
 Some may be too large to be accepted by clients.
 
 Some of these will be too small to be accepted by clients.
 Some may be too large to be accepted by clients.
 

+The TLS protocol does not negotiate an acceptable size for this; clients tend
+to hard-drop connections if what is offered by the server is unacceptable,
+whether too large or too small, and there's no provision for the client to
+tell the server what these constraints are.  Thus, as a server operator, you
+need to make an educated guess as to what is most likely to work for your
+userbase.
+
+Some known size constraints suggest that a bit-size in the range 2048 to 2236
+is most likely to maximise interoperability.  The upper bound comes from
+applications using the Mozilla Network Security Services (NSS) library, which
+used to set its &`DH_MAX_P_BITS`& upper-bound to 2236.  This affects many
+mail user agents (MUAs). The lower bound comes from Debian installs of Exim4
+prior to the 4.80 release, as Debian used to patch Exim to raise the minimum
+acceptable bound from 1024 to 2048.
+

 
 .option tls_on_connect_ports main "string list" unset
 This option specifies a list of incoming SSMTP (aka SMTPS) ports that should
 
 .option tls_on_connect_ports main "string list" unset
 This option specifies a list of incoming SSMTP (aka SMTPS) ports that should


@@ -23550,7 +23610,7 @@ In practice, almost all rules start with a domain name pattern without a local
 part.
 
 .cindex "regular expressions" "in retry rules"
 part.
 
 .cindex "regular expressions" "in retry rules"

-&*Warning*&: If you use a regular expression in a routing rule pattern, it
+&*Warning*&: If you use a regular expression in a retry rule pattern, it

 must match a complete address, not just a domain, because that is how regular
 expressions work in address lists.
 .display
 must match a complete address, not just a domain, because that is how regular
 expressions work in address lists.
 .display


@@ -24533,7 +24593,8 @@ to be returned. If the result of a successful expansion is an empty string,
 expansion is &"1"&, &"yes"&, or &"true"&, authentication succeeds and the
 generic &%server_set_id%& option is expanded and saved in &$authenticated_id$&.
 For any other result, a temporary error code is returned, with the expanded
 expansion is &"1"&, &"yes"&, or &"true"&, authentication succeeds and the
 generic &%server_set_id%& option is expanded and saved in &$authenticated_id$&.
 For any other result, a temporary error code is returned, with the expanded

-string as the error text.
+string as the error text, and the failed id saved in
+&$authenticated_fail_id$&.

 
 &*Warning*&: If you use a lookup in the expansion to find the user's
 password, be sure to make the authentication fail if the user is unknown.
 
 &*Warning*&: If you use a lookup in the expansion to find the user's
 password, be sure to make the authentication fail if the user is unknown.


@@ -25686,7 +25747,7 @@ tls_dhparam = none
 This may also be set to a string identifying a standard prime to be used for
 DH; if it is set to &`default`& or, for OpenSSL, is unset, then the prime
 used is &`ike23`&.  There are a few standard primes available, see the
 This may also be set to a string identifying a standard prime to be used for
 DH; if it is set to &`default`& or, for OpenSSL, is unset, then the prime
 used is &`ike23`&.  There are a few standard primes available, see the

-documetnation for &%tls_dhparam%& for the complete list.
+documentation for &%tls_dhparam%& for the complete list.

 
 See the command
 .code
 
 See the command
 .code


@@ -36387,7 +36448,7 @@ integer size comparisons against this value.
 A colon-separated list of names of headers included in the signature.
 .vitem &%$dkim_key_testing%&
 "1" if the key record has the "testing" flag set, "0" if not.
 A colon-separated list of names of headers included in the signature.
 .vitem &%$dkim_key_testing%&
 "1" if the key record has the "testing" flag set, "0" if not.

-.vitem &%$nosubdomains%&
+.vitem &%$dkim_key_nosubdomains%&

 "1" if the key record forbids subdomaining, "0" otherwise.
 .vitem &%$dkim_key_srvtype%&
 Service type (tag s=) from the key record. Defaults to "*" if not specified
 "1" if the key record forbids subdomaining, "0" otherwise.
 .vitem &%$dkim_key_srvtype%&
 Service type (tag s=) from the key record. Defaults to "*" if not specified