. Update the Copyright year (only) when changing content.
. /////////////////////////////////////////////////////////////////////////////
-.set previousversion "4.80"
+.set previousversion "4.83"
.include ./local_params
.set ACL "access control lists (ACLs)"
by Exim in conjunction with the &%-MC%& option. It signifies that the
connection to the remote host has been authenticated.
+.vitem &%-MCD%&
+.oindex "&%-MCD%&"
+This option is not intended for use by external callers. It is used internally
+by Exim in conjunction with the &%-MC%& option. It signifies that the
+remote host supports the ESMTP &_DSN_& extension.
+
.vitem &%-MCP%&
.oindex "&%-MCP%&"
This option is not intended for use by external callers. It is used internally
using the same syntax as for &%-oMa%&. The interface address is placed in
&$received_ip_address$& and the port number, if present, in &$received_port$&.
+.vitem &%-oMm%&&~<&'message&~reference'&>
+.oindex "&%-oMm%&"
+.cindex "message reference" "message reference, specifying for local message"
+See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMm%&
+option sets the message reference, e.g. message-id, and is logged during
+delivery. This is useful when some kind of audit trail is required to tie
+messages together. The format of the message reference is checked and will
+abort if the format is invalid. The option will only be accepted if exim is
+running in trusted mode, not as any regular user.
+
+The best example of a message reference is when Exim sends a bounce message.
+The message reference is the message-id of the original message for which Exim
+is sending the bounce.
+
.vitem &%-oMr%&&~<&'protocol&~name'&>
.oindex "&%-oMr%&"
.cindex "protocol, specifying for local message"
1413 (hence their names):
.code
rfc1413_hosts = *
-rfc1413_query_timeout = 5s
+rfc1413_query_timeout = 0s
+.endd
+These settings cause Exim to avoid ident callbacks for all incoming SMTP calls.
+Few hosts offer RFC1413 service these days; calls have to be
+terminated by a timeout and this needlessly delays the startup
+of an incoming SMTP connection.
+If you have hosts for which you trust RFC1413 and need this
+information, you can change this.
+
+This line enables an efficiency SMTP option. It is negociated by clients
+and not expected to cause problems but can be disabled if needed.
+.code
+prdr_enable = true
.endd
-These settings cause Exim to make ident callbacks for all incoming SMTP calls.
-You can limit the hosts to which these calls are made, or change the timeout
-that is used. If you set the timeout to zero, all ident calls are disabled.
-Although they are cheap and can provide useful information for tracing problem
-messages, some hosts and firewalls have problems with ident calls. This can
-result in a timeout instead of an immediate refused connection, leading to
-delays on starting up an incoming SMTP session.
When Exim receives messages over SMTP connections, it expects all addresses to
be fully qualified with a domain, as required by the SMTP definition. However,
.code
remote_smtp:
driver = smtp
+ hosts_try_prdr = *
.endd
-This transport is used for delivering messages over SMTP connections. All its
-options are defaulted. The list of remote hosts comes from the router.
+This transport is used for delivering messages over SMTP connections.
+The list of remote hosts comes from the router.
+The &%hosts_try_prdr%& option enables an efficiency SMTP option.
+It is negotiated between client and server
+and not expected to cause problems but can be disabled if needed.
+All other options are defaulted.
.code
local_delivery:
driver = appendfile
If the data for a PTR record is not a syntactically valid IP address, it is not
altered and nothing is added.
-.cindex "MX record" "in &(dnsdb)& lookup"
-.cindex "SRV record" "in &(dnsdb)& lookup"
-For an MX lookup, both the preference value and the host name are returned for
-each record, separated by a space. For an SRV lookup, the priority, weight,
-port, and host name are returned for each record, separated by spaces.
-
For any record type, if multiple records are found (or, for A6 lookups, if a
single record leads to multiple addresses), the data is returned as a
concatenation, with newline as the default separator. The order, of course,
It is permitted to specify a space as the separator character. Further
white space is ignored.
+.cindex "MX record" "in &(dnsdb)& lookup"
+.cindex "SRV record" "in &(dnsdb)& lookup"
+For an MX lookup, both the preference value and the host name are returned for
+each record, separated by a space. For an SRV lookup, the priority, weight,
+port, and host name are returned for each record, separated by spaces.
+.new
+An alternate field separator can be specified using a comma after the main
+separator character, followed immediately by the field separator.
+.wen
+
.cindex "TXT record" "in &(dnsdb)& lookup"
.cindex "SPF record" "in &(dnsdb)& lookup"
For TXT records with multiple items of data, only the first item is returned,
Thus, in the default case, as long as at least one of the DNS lookups
yields some data, the lookup succeeds.
-.new
.cindex "DNSSEC" "dns lookup"
Use of &(DNSSEC)& is controlled by a dnssec modifier.
The possible keywords are
The default is &"never"&.
See also the &$lookup_dnssec_authenticated$& variable.
-.wen
LDAP connections, rather than the SSL-on-connect &`ldaps`&.
See the &%ldap_start_tls%& option.
-.new
Starting with Exim 4.83, the initialization of LDAP with TLS is more tightly
controlled. Every part of the TLS configuration can be configured by settings in
&_exim.conf_&. Depending on the version of the client libraries installed on
running as could affect which config files it read. With Exim 4.83, these
methods become optional, only taking effect if not specifically set in
&_exim.conf_&.
-.wen
.section "LDAP quoting" "SECID68"
&`USER `& set the DN, for authenticating the LDAP bind
&`PASS `& set the password, likewise
&`REFERRALS `& set the referrals parameter
-.new
&`SERVERS `& set alternate server list for this query only
-.wen
&`SIZE `& set the limit for the number of entries returned
&`TIME `& set the maximum waiting time for a query
.endd
The TIME parameter (also a number of seconds) is passed to the server to
set a server-side limit on the time taken to complete a search.
-.new
The SERVERS parameter allows you to specify an alternate list of ldap servers
to use for an individual lookup. The global ldap_servers option provides a
default list of ldap servers, and a single lookup can specify a single ldap
server to use. But when you need to do a lookup with a list of servers that is
different than the default list (maybe different order, maybe a completely
different set of servers), the SERVERS parameter allows you to specify this
-alternate list.
-.wen
+alternate list (colon-separated).
Here is an example of an LDAP query in an Exim lookup that uses some of these
values. This is a single line, folded to fit on the page:
strings, each preceded by the attribute name and an equals sign. Within the
quotes, the quote character, backslash, and newline are escaped with
backslashes, and commas are used to separate multiple values for the attribute.
+.new
+Any commas in attribute values are doubled
+(permitting treatment of the values as a comma-separated list).
+.wen
Apart from the escaping, the string within quotes takes the same form as the
output when a single attribute is requested. Specifying no attributes is the
same as specifying all of an entry's attributes.
+.new
Here are some examples of the output format. The first line of each pair is an
LDAP query, and the second is the data that is returned. The attribute called
-&%attr1%& has two values, whereas &%attr2%& has only one value:
+&%attr1%& has two values, one of them with an embedded comma, whereas
+&%attr2%& has only one value:
.code
ldap:///o=base?attr1?sub?(uid=fred)
-value1.1, value1.2
+value1.1,value1,,2
ldap:///o=base?attr2?sub?(uid=fred)
value two
ldap:///o=base?attr1,attr2?sub?(uid=fred)
-attr1="value1.1, value1.2" attr2="value two"
+attr1="value1.1,value1,,2" attr2="value two"
ldap:///o=base??sub?(uid=fred)
-objectClass="top" attr1="value1.1, value1.2" attr2="value two"
+objectClass="top" attr1="value1.1,value1,,2" attr2="value two"
.endd
-The &%extract%& operator in string expansions can be used to pick out
-individual fields from data that consists of &'key'&=&'value'& pairs. You can
+.wen
+You can
make use of Exim's &%-be%& option to run expansion tests and thereby check the
results of LDAP lookups.
+The &%extract%& operator in string expansions can be used to pick out
+individual fields from data that consists of &'key'&=&'value'& pairs.
+.new
+The &%listextract%& operator should be used to pick out individual values
+of attributes, even when only a single value is expected.
+The doubling of embedded commas allows you to use the returned data as a
+comma separated list (using the "<," syntax for changing the input list separator).
+.wen
list. The effect of each one lasts until the next, or until the end of the
list.
-.new
.section "Mixing wildcarded host names and addresses in host lists" &&&
"SECTmixwilhos"
.cindex "host list" "mixing names and addresses in"
&`+ignore_unknown`&, which was discussed in depth in the first example in
this section.
.endlist
-.wen
.section "Temporary DNS errors when looking up host information" &&&
If the ACL returns defer the result is a forced-fail. Otherwise the expansion fails.
+.vitem "&*${certextract{*&<&'field'&>&*}{*&<&'certificate'&>&*}&&&
+ {*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&"
+.cindex "expansion" "extracting cerificate fields"
+.cindex "&%certextract%&" "certificate fields"
+.cindex "certificate" "extracting fields"
+The <&'certificate'&> must be a variable of type certificate.
+The field name is expanded and used to retrive the relevant field from
+the certificate. Supported fields are:
+.display
+&`version `&
+&`serial_number `&
+&`subject `& RFC4514 DN
+&`issuer `& RFC4514 DN
+&`notbefore `& time
+&`notafter `& time
+&`sig_algorithm `&
+&`signature `&
+&`subj_altname `& tagged list
+&`ocsp_uri `& list
+&`crl_uri `& list
+.endd
+If the field is found,
+<&'string2'&> is expanded, and replaces the whole item;
+otherwise <&'string3'&> is used. During the expansion of <&'string2'&> the
+variable &$value$& contains the value that has been extracted. Afterwards, it
+is restored to any previous value it might have had.
+
+If {<&'string3'&>} is omitted, the item is replaced by an empty string if the
+key is not found. If {<&'string2'&>} is also omitted, the value that was
+extracted is used.
+
+Some field names take optional modifiers, appended and separated by commas.
+
+The field selectors marked as "RFC4514" above
+output a Distinguished Name string which is
+not quite
+parseable by Exim as a comma-separated tagged list
+(the exceptions being elements containin commas).
+RDN elements of a single type may be selected by
+a modifier of the type label; if so the expansion
+result is a list (newline-separated by default).
+The separator may be changed by another modifer of
+a right angle-bracket followed immediately by the new separator.
+Recognised RDN type labels include "CN", "O", "OU" and "DC".
+
+The field selectors marked as "time" above
+take an optional modifier of "int"
+for which the result is the number of seconds since epoch.
+Otherwise the result is a human-readable string
+in the timezone selected by the main "timezone" option.
+
+The field selectors marked as "list" above return a list,
+newline-separated by default,
+(embedded separator characters in elements are doubled).
+The separator may be changed by a modifier of
+a right angle-bracket followed immediately by the new separator.
+
+The field selectors marked as "tagged" above
+prefix each list element with a type string and an equals sign.
+Elements of only one type may be selected by a modifier
+which is one of "dns", "uri" or "mail";
+if so the elenment tags are omitted.
+
+If not otherwise noted field values are presented in human-readable form.
+
.vitem "&*${dlfunc{*&<&'file'&>&*}{*&<&'function'&>&*}{*&<&'arg'&>&*}&&&
{*&<&'arg'&>&*}...}*&"
.cindex &%dlfunc%&
{*&<&'string2'&>&*}}*&"
.cindex "expansion" "running a command"
.cindex "&%run%& expansion item"
-The command and its arguments are first expanded separately, and then the
-command is run in a separate process, but under the same uid and gid. As in
-other command executions from Exim, a shell is not used by default. If you want
+The command and its arguments are first expanded as one string. The string is
+split apart into individual arguments by spaces, and then the command is run
+in a separate process, but under the same uid and gid. As in other command
+executions from Exim, a shell is not used by default. If the command requires
a shell, you must explicitly code it.
+Since the arguments are split by spaces, when there is a variable expansion
+which has an empty result, it will cause the situation that the argument will
+simply be omitted when the program is actually executed by Exim. If the
+script/program requires a specific number of arguments and the expanded
+variable could possibly result in this empty expansion, the variable must be
+quoted. This is more difficult if the expanded variable itself could result
+in a string containing quotes, because it would interfere with the quotes
+around the command arguments. A possible guard against this is to wrap the
+variable in the &%sg%& operator to change any quote marks to some other
+character.
+
The standard input for the command exists, but is empty. The standard output
and standard error are set to the same file descriptor.
.cindex "return code" "from &%run%& expansion"
+.new
+.vitem &*${sort{*&<&'string'&>&*}{*&<&'comparator'&>&*}{*&<&'extractor'&>&*}}*&
+.cindex sorting a list
+.cindex list sorting
+After expansion, <&'string'&> is interpreted as a list, colon-separated by
+default, but the separator can be changed in the usual way.
+The <&'comparator'&> argument is interpreted as the operator
+of a two-argument expansion condition.
+The numeric operators plus ge, gt, le, lt (and ~i variants) are supported.
+The comparison should return true when applied to two values
+if the first value should sort before the second value.
+The <&'extractor'&> expansion is applied repeatedly to elements of the list,
+the element being placed in &$item$&,
+to give values for comparison.
+
+The item result is a sorted list,
+with the original list separator,
+of the list elements (in full) of the original.
+
+Examples:
+.code
+${sort{3:2:1:4}{<}{$item}}
+.endd
+sorts a list of numbers, and
+.code
+${sort {$lookup dnsdb{>:,,mx=example.com}} {<} {${listextract{1}{<,$item}}}}
+.endd
+will sort an MX lookup into priority order.
+.wen
+
+
.vitem &*${substr{*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&
.cindex "&%substr%& expansion item"
.cindex "substring extraction"
.vitem &*${md5:*&<&'string'&>&*}*&
.cindex "MD5 hash"
.cindex "expansion" "MD5 hash"
+.cindex "certificate fingerprint"
.cindex "&%md5%& expansion item"
The &%md5%& operator computes the MD5 hash value of the string, and returns it
as a 32-digit hexadecimal number, in which any letters are in lower case.
.vitem &*${sha1:*&<&'string'&>&*}*&
.cindex "SHA-1 hash"
.cindex "expansion" "SHA-1 hashing"
+.cindex "certificate fingerprint"
.cindex "&%sha2%& expansion item"
The &%sha1%& operator computes the SHA-1 hash value of the string, and returns
it as a 40-digit hexadecimal number, in which any letters are in upper case.
+.vitem &*${sha256:*&<&'certificate'&>&*}*&
+.cindex "SHA-256 hash"
+.cindex "certificate fingerprint"
+.cindex "expansion" "SHA-256 hashing"
+.cindex "&%sha256%& expansion item"
+The &%sha256%& operator computes the SHA-256 hash fingerprint of the
+certificate,
+and returns
+it as a 64-digit hexadecimal number, in which any letters are in upper case.
+Only arguments which are a single variable of certificate type are supported.
+
+
.vitem &*${stat:*&<&'string'&>&*}*&
.cindex "expansion" "statting a file"
.cindex "file" "extracting characteristics"
Exim filter files include an &%if%& command with its own regular expression
matching condition.
+.vitem "&$acl_arg1$&, &$acl_arg2$&, etc"
+Within an acl condition, expansion condition or expansion item
+any arguments are copied to these variables,
+any unused variables being made empty.
+
.vitem "&$acl_c...$&"
Values can be placed in these variables by the &%set%& modifier in an ACL. They
can be given any name that starts with &$acl_c$& and is at least six characters
and can be accessed by filters, routers, and transports during subsequent
delivery.
+.vitem &$acl_narg$&
+Within an acl condition, expansion condition or expansion item
+this variable has the number of arguments.
+
.vitem &$acl_verify_message$&
.vindex "&$acl_verify_message$&"
After an address verification has failed, this variable contains the failure
of times it has been compiled. This serves to distinguish different
compilations of the same version of the program.
+.vitem &$config_dir$&
+.vindex "&$config_dir$&"
+The directory name of the main configuration file. That is, the content of
+&$config_file$& with the last component stripped. The value does not
+contain the trailing slash. If &$config_file$& does not contain a slash,
+&$config_dir$& is ".".
+
+.vitem &$config_file$&
+.vindex "&$config_file$&"
+The name of the main configuration file Exim is using.
+
.vitem &$demime_errorlevel$&
.vindex "&$demime_errorlevel$&"
This variable is available when Exim is compiled with
.vindex "&$exim_uid$&"
This variable contains the numerical value of the Exim user id.
+.vitem &$exim_version$&
+.vindex "&$exim_uid$&"
+This variable contains the version string of the Exim build.
+The first character is a major version number, currently 4.
+Then after a dot, the next group of digits is a minor version number.
+There may be other characters following the minor version.
+
.vitem &$found_extension$&
.vindex "&$found_extension$&"
This variable is available when Exim is compiled with the
.vindex "&$host_lookup_failed$&"
See &$host_lookup_deferred$&.
+.vitem &$host_port$&
+.vindex "&$host_port$&"
+This variable is set to the remote host's TCP port whenever &$host$& is set
+for an outbound connection.
+
.vitem &$inode$&
.vindex "&$inode$&"
the space value is -1. See also the &%check_log_space%& option.
-.new
.vitem &$lookup_dnssec_authenticated$&
.vindex "&$lookup_dnssec_authenticated$&"
This variable is set after a DNS lookup done by
-either a dnslookup router or a dnsdb lookup expansion.
+a dnsdb lookup expansion, dnslookup router or smtp transport.
It will be empty if &(DNSSEC)& was not requested,
&"no"& if the result was not labelled as authenticated data
and &"yes"& if it was.
-.wen
.vitem &$mailstore_basename$&
.vindex "&$mailstore_basename$&"
contents of header lines is done.
.vitem &$message_id$&
-This is an old name for &$message_exim_id$&, which is now deprecated.
+This is an old name for &$message_exim_id$&. It is now deprecated.
.vitem &$message_linecount$&
.vindex "&$message_linecount$&"
.vitem &$sender_host_address$&
.vindex "&$sender_host_address$&"
-When a message is received from a remote host, this variable contains that
-host's IP address. For locally submitted messages, it is empty.
+When a message is received from a remote host using SMTP,
+this variable contains that
+host's IP address. For locally non-SMTP submitted messages, it is empty.
.vitem &$sender_host_authenticated$&
.vindex "&$sender_host_authenticated$&"
.vitem &$sender_host_dnssec$&
.vindex "&$sender_host_dnssec$&"
-If &$sender_host_name$& has been populated (by reference, &%hosts_lookup%& or
+If an attempt to populate &$sender_host_name$& has been made
+(by reference, &%hosts_lookup%& or
otherwise) then this boolean will have been set true if, and only if, the
resolver library states that the reverse DNS was authenticated data. At all
other times, this variable is false.
this depends upon the TLS implementation used.
If TLS has not been negotiated, the value will be 0.
+.vitem &$tls_in_ourcert$&
+.vindex "&$tls_in_ourcert$&"
+This variable refers to the certificate presented to the peer of an
+inbound connection when the message was received.
+It is only useful as the argument of a
+.new
+&%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
+.wen
+or a &%def%& condition.
+
+.vitem &$tls_in_peercert$&
+.vindex "&$tls_in_peercert$&"
+This variable refers to the certificate presented by the peer of an
+inbound connection when the message was received.
+It is only useful as the argument of a
+.new
+&%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
+.wen
+or a &%def%& condition.
+
+.vitem &$tls_out_ourcert$&
+.vindex "&$tls_out_ourcert$&"
+This variable refers to the certificate presented to the peer of an
+outbound connection. It is only useful as the argument of a
+.new
+&%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
+.wen
+or a &%def%& condition.
+
+.vitem &$tls_out_peercert$&
+.vindex "&$tls_out_peercert$&"
+This variable refers to the certificate presented by the peer of an
+outbound connection. It is only useful as the argument of a
+.new
+&%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
+.wen
+or a &%def%& condition.
+
.vitem &$tls_in_certificate_verified$&
.vindex "&$tls_in_certificate_verified$&"
This variable is set to &"1"& if a TLS certificate was verified when the
&<<CHAPTLS>>& for details of TLS support and chapter &<<CHAPsmtptrans>>& for
details of the &(smtp)& transport.
+.vitem &$tls_in_ocsp$&
+.vindex "&$tls_in_ocsp$&"
+When a message is received from a remote client connection
+the result of any OCSP request from the client is encoded in this variable:
+.code
+0 OCSP proof was not requested (default value)
+1 No response to request
+2 Response not verified
+3 Verification failed
+4 Verification succeeded
+.endd
+
+.vitem &$tls_out_ocsp$&
+.vindex "&$tls_out_ocsp$&"
+When a message is sent to a remote host connection
+the result of any OCSP request made is encoded in this variable.
+See &$tls_in_ocsp$& for values.
+
.vitem &$tls_in_peerdn$&
.vindex "&$tls_in_peerdn$&"
.vindex "&$tls_peerdn$&"
or external command, as described above. It is also used during a
&*reduce*& expansion.
+.vitem &$verify_mode$&
+.vindex "&$verify_mode$&"
+While a router or transport is being run in verify mode
+or for cutthrough delivery,
+contains "S" for sender-verification or "R" for recipient-verification.
+Otherwise, empty.
+
.vitem &$version_number$&
.vindex "&$version_number$&"
The version number of Exim.
following options:
.ilist
-&%daemon_smtp_ports%& contains a list of default ports. (For backward
-compatibility, this option can also be specified in the singular.)
+&%daemon_smtp_ports%& contains a list of default ports
+or service names.
+(For backward compatibility, this option can also be specified in the singular.)
.next
&%local_interfaces%& contains list of interface IP addresses on which to
listen. Each item may optionally also specify a port.
Exim supports the obsolete SSMTP protocol (also known as SMTPS) that was used
before the STARTTLS command was standardized for SMTP. Some legacy clients
still use this protocol. If the &%tls_on_connect_ports%& option is set to a
-list of port numbers, connections to those ports must use SSMTP. The most
+list of port numbers or service names,
+connections to those ports must use SSMTP. The most
common use of this option is expected to be
.code
tls_on_connect_ports = 465
.row &%acl_smtp_auth%& "ACL for AUTH"
.row &%acl_smtp_connect%& "ACL for connection"
.row &%acl_smtp_data%& "ACL for DATA"
+.row &%acl_smtp_data_prdr%& "ACL for DATA, per-recipient"
.row &%acl_smtp_dkim%& "ACL for DKIM verification"
.row &%acl_smtp_etrn%& "ACL for ETRN"
.row &%acl_smtp_expn%& "ACL for EXPN"
.row &%tls_crl%& "certificate revocation list"
.row &%tls_dh_max_bits%& "clamp D-H bit count suggestion"
.row &%tls_dhparam%& "DH parameters for server"
+.row &%tls_ocsp_file%& "location of server certificate status proof"
.row &%tls_on_connect_ports%& "specify SSMTP (SMTPS) ports"
.row &%tls_privatekey%& "location of server private key"
.row &%tls_remember_esmtp%& "don't reset after starting TLS"
.table2
.row &%accept_8bitmime%& "advertise 8BITMIME"
.row &%auth_advertise_hosts%& "advertise AUTH to these hosts"
+.row &%dsn_advertise_hosts%& "advertise DSN extensions to these hosts"
.row &%ignore_fromline_hosts%& "allow &""From ""& from these hosts"
.row &%ignore_fromline_local%& "allow &""From ""& from local SMTP"
.row &%pipelining_advertise_hosts%& "advertise pipelining to these hosts"
+.row &%prdr_enable%& "advertise PRDR to all hosts"
.row &%tls_advertise_hosts%& "advertise TLS to these hosts"
.endtable
processed and the message itself has been received, but before the final
acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
+.option acl_smtp_data_prdr main string&!! accept
+.cindex "PRDR" "ACL for"
+.cindex "DATA" "PRDR ACL for"
+.cindex "&ACL;" "PRDR-related"
+.cindex "&ACL;" "per-user data processing"
+This option defines the ACL that,
+if the PRDR feature has been negotiated,
+is run for each recipient after an SMTP DATA command has been
+processed and the message itself has been received, but before the
+acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
+
.option acl_smtp_etrn main string&!! unset
.cindex "ETRN" "ACL for"
This option defines the ACL that is run when an SMTP ETRN command is
handled CR and LF characters in incoming messages. What happens now is
described in section &<<SECTlineendings>>&.
+.option dsn_advertise_hosts main "host list&!!" unset
+.cindex "bounce messages" "success"
+.cindex "DSN" "success"
+.cindex "Delivery Status Notification" "success"
+DSN extensions (RFC3461) will be advertised in the EHLO message to,
+and accepted from, these hosts.
+Hosts may use the NOTIFY and ENVID options on RCPT TO commands,
+and RET and ORCPT options on MAIL FROM commands.
+A NOTIFY=SUCCESS option requests success-DSN messages.
+A NOTIFY= option with no argument requests that no delay or failure DSNs
+are sent.
+
.option dsn_from main "string&!!" "see below"
.cindex "&'From:'& header line" "in bounces"
.cindex "bounce messages" "&'From:'& line, specifying"
adjusted lightly. An unrecognised item will be detected at startup, by
invoking Exim with the &%-bV%& flag.
+The option affects Exim operating both as a server and as a client.
+
Historical note: prior to release 4.80, Exim defaulted this value to
"+dont_insert_empty_fragments", which may still be needed for compatibility
with some clients, but which lowers security by increasing exposure to
some now infamous attacks.
-An example:
+Examples:
.code
# Make both old MS and old Eudora happy:
openssl_options = -all +microsoft_big_sslv3_buffer \
+dont_insert_empty_fragments
+
+# Disable older protocol versions:
+openssl_options = +no_sslv2 +no_sslv3
.endd
Possible options may include:
not count as protocol errors (see &%smtp_max_synprot_errors%&).
+.option prdr_enable main boolean false
+.cindex "PRDR" "enabling on server"
+This option can be used to enable the Per-Recipient Data Response extension
+to SMTP, defined by Eric Hall.
+If the option is set, PRDR is advertised by Exim when operating as a server.
+If the client requests PRDR, and more than one recipient, for a message
+an additional ACL is called for each recipient after the message content
+is recieved. See section &<<SECTPRDRACL>>&.
+
.option preserve_message_logs main boolean false
.cindex "message logs" "preserving"
If this option is set, message log files are not deleted when messages are
This option is an obsolete synonym for &%bounce_return_size_limit%&.
-.option rfc1413_hosts main "host list&!!" *
+.option rfc1413_hosts main "host list&!!" @[]
.cindex "RFC 1413"
.cindex "host" "for RFC 1413 calls"
-RFC 1413 identification calls are made to any client host which matches an item
-in the list.
+RFC 1413 identification calls are made to any client host which matches
+an item in the list.
+The default value specifies just this host, being any local interface
+for the system.
-.option rfc1413_query_timeout main time 5s
+.option rfc1413_query_timeout main time 0s
.cindex "RFC 1413" "query timeout"
.cindex "timeout" "for RFC 1413 call"
This sets the timeout on RFC 1413 identification calls. If it is set to zero,
acceptable bound from 1024 to 2048.
+.option tls_ocsp_file main string&!! unset
+This option
+must if set expand to the absolute path to a file which contains a current
+status proof for the server's certificate, as obtained from the
+Certificate Authority.
+
+
.option tls_on_connect_ports main "string list" unset
This option specifies a list of incoming SSMTP (aka SMTPS) ports that should
operate the obsolete SSMTP (SMTPS) protocol, where a TLS session is immediately
See &%tls_verify_hosts%& below.
-.option tls_verify_certificates main string&!! unset
+.option tls_verify_certificates main string&!! system
.cindex "TLS" "client certificate verification"
.cindex "certificate" "verification of client"
-The value of this option is expanded, and must then be the absolute path to
-a file containing permitted certificates for clients that
-match &%tls_verify_hosts%& or &%tls_try_verify_hosts%&. Alternatively, if you
-are using OpenSSL, you can set &%tls_verify_certificates%& to the name of a
-directory containing certificate files. This does not work with GnuTLS; the
-option must be set to the name of a single file if you are using GnuTLS.
+The value of this option is expanded, and must then be either the
+word "system"
+or the absolute path to
+a file or directory containing permitted certificates for clients that
+match &%tls_verify_hosts%& or &%tls_try_verify_hosts%&.
+
+The "system" value for the option will use a
+system default location compiled into the SSL library.
+This is not available for GnuTLS versions preceding 3.0.20,
+and will be taken as empty; an explicit location
+must be specified.
+
+The use of a directory for the option value is not avilable for GnuTLS versions
+preceding 3.3.6 and a single file must be used.
+
+With OpenSSL the certificates specified
+explicitly
+either by file or directory
+are added to those given by the system default location.
These certificates should be for the certificate authorities trusted, rather
than the public cert of individual clients. With both OpenSSL and GnuTLS, if
the value is a file then the certificates are sent by Exim as a server to
connecting clients, defining the list of accepted certificate authorities.
Thus the values defined should be considered public data. To avoid this,
-use OpenSSL with a directory.
+use the explicit directory version.
See &<<SECTtlssni>>& for discussion of when this option might be re-expanded.
of the other precondition options are common special cases that could in fact
be specified using &%condition%&.
+.new
+Historical note: We have &%condition%& on ACLs and on Routers. Routers
+are far older, and use one set of semantics. ACLs are newer and when
+they were created, the ACL &%condition%& process was given far stricter
+parse semantics. The &%bool{}%& expansion condition uses the same rules as
+ACLs. The &%bool_lax{}%& expansion condition uses the same rules as
+Routers. More pointedly, the &%bool_lax{}%& was written to match the existing
+Router rules processing behavior.
+
+This is best illustrated in an example:
+.code
+# If used in an ACL condition will fail with a syntax error, but
+# in a router condition any extra characters are treated as a string
+
+$ exim -be '${if eq {${lc:GOOGLE.com}} {google.com}} {yes} {no}}'
+true {yes} {no}}
+
+$ exim -be '${if eq {${lc:WHOIS.com}} {google.com}} {yes} {no}}'
+ {yes} {no}}
+.endd
+In each example above, the &%if%& statement actually ends after
+&"{google.com}}"&. Since no true or false braces were defined, the
+default &%if%& behavior is to return a boolean true or a null answer
+(which evaluates to false). The rest of the line is then treated as a
+string. So the first example resulted in the boolean answer &"true"&
+with the string &" {yes} {no}}"& appended to it. The second example
+resulted in the null output (indicating false) with the string
+&" {yes} {no}}"& appended to it.
+
+In fact you can put excess forward braces in too. In the router
+&%condition%&, Exim's parser only looks for &"{"& symbols when they
+mean something, like after a &"$"& or when required as part of a
+conditional. But otherwise &"{"& and &"}"& are treated as ordinary
+string characters.
+
+Thus, in a Router, the above expansion strings will both always evaluate
+true, as the result of expansion is a non-empty string which doesn't
+match an explicit false value. This can be tricky to debug. By
+contrast, in an ACL either of those strings will always result in an
+expansion error because the result doesn't look sufficiently boolean.
+.wen
+
.option debug_print routers string&!! unset
.cindex "testing" "variables in drivers"
to be used.
+.option dsn_lasthop routers boolean false
+.cindex "DSN" "success"
+.cindex "Delivery Status Notification" "success"
+If this option is set true, and extended DSN (RFC3461) processing is in effect,
+Exim will not pass on DSN requests to downstream DSN-aware hosts but will
+instead send a success DSN as if the next hop does not support DSN.
+Not effective on redirect routers.
+
+
.option errors_to routers string&!! unset
.cindex "envelope sender"
or testing recipient verification using &%-bv%&.
See section &<<SECTrouprecon>>& for a list of the order in which preconditions
are evaluated.
+See also the &$verify_mode$& variable.
.option verify_sender routers&!? boolean true
or testing sender verification using &%-bvs%&.
See section &<<SECTrouprecon>>& for a list of the order in which preconditions
are evaluated.
+See also the &$verify_mode$& variable.
.ecindex IIDgenoprou1
.ecindex IIDgenoprou2
-.new
.option dnssec_request_domains dnslookup "domain list&!!" unset
.cindex "MX record" "security"
.cindex "DNSSEC" "MX lookup"
the dnssec request bit set.
This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
-See also the &$lookup_dnssec_authenticated$& variable.
-.wen
-
-.new
.option dnssec_require_domains dnslookup "domain list&!!" unset
.cindex "MX record" "security"
.cindex "DNSSEC" "MX lookup"
the dnssec request bit set. Any returns not having the Authenticated Data bit
(AD bit) set wil be ignored and logged as a host-lookup failure.
This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
-.wen
files and pipes, and for generating autoreplies. See the &%file_transport%&,
&%pipe_transport%& and &%reply_transport%& descriptions below.
+If success DSNs have been requested
+.cindex "DSN" "success"
+.cindex "Delivery Status Notification" "success"
+redirection triggers one and the DSN options are not passed any further.
+
.section "Redirection data" "SECID124"
details.
+.option dnssec_request_domains smtp "domain list&!!" unset
+.cindex "MX record" "security"
+.cindex "DNSSEC" "MX lookup"
+.cindex "security" "MX lookup"
+.cindex "DNS" "DNSSEC"
+DNS lookups for domains matching &%dnssec_request_domains%& will be done with
+the dnssec request bit set.
+This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+
+
+
+.option dnssec_require_domains smtp "domain list&!!" unset
+.cindex "MX record" "security"
+.cindex "DNSSEC" "MX lookup"
+.cindex "security" "MX lookup"
+.cindex "DNS" "DNSSEC"
+DNS lookups for domains matching &%dnssec_request_domains%& will be done with
+the dnssec request bit set. Any returns not having the Authenticated Data bit
+(AD bit) set wil be ignored and logged as a host-lookup failure.
+This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+
+
+
.option dscp smtp string&!! unset
.cindex "DCSP" "outbound"
This option causes the DSCP value associated with a socket to be set to one
&<<CHAPSMTPAUTH>>& for details of authentication.
+.option hosts_request_ocsp smtp "host list&!!" *
+.cindex "TLS" "requiring for certain servers"
+Exim will request a Certificate Status on a
+TLS session for any host that matches this list.
+&%tls_verify_certificates%& should also be set for the transport.
+
+.option hosts_require_ocsp smtp "host list&!!" unset
+.cindex "TLS" "requiring for certain servers"
+Exim will request, and check for a valid Certificate Status being given, on a
+TLS session for any host that matches this list.
+&%tls_verify_certificates%& should also be set for the transport.
+
.option hosts_require_tls smtp "host list&!!" unset
.cindex "TLS" "requiring for certain servers"
Exim will insist on using a TLS session when delivering to any host that
unauthenticated. See also &%hosts_require_auth%&, and chapter
&<<CHAPSMTPAUTH>>& for details of authentication.
+.option hosts_try_prdr smtp "host list&!!" *
+.cindex "PRDR" "enabling, optional in client"
+This option provides a list of servers to which, provided they announce
+PRDR support, Exim will attempt to negotiate PRDR
+for multi-recipient messages.
+The option can usually be left as default.
+
.option interface smtp "string list&!!" unset
.cindex "bind IP address"
.cindex "IP address" "binding"
permits this.
-.option multi_domain smtp boolean true
+.option multi_domain smtp boolean&!! true
.vindex "&$domain$&"
When this option is set, the &(smtp)& transport can handle a number of
addresses containing a mixture of different domains provided they all resolve
&$domain$& in an expansion for the transport, because it is set only when there
is a single domain involved in a remote delivery.
+It is expanded per-address and can depend on any of
+&$address_data$&, &$domain_data$&, &$local_part_data$&,
+&$host$&, &$host_address$& and &$host_port$&.
.option port smtp string&!! "see below"
.cindex "port" "sending TCP/IP"
The Internet standards bodies strongly discourage use of this mode.
-.option retry_include_ip_address smtp boolean true
+.option retry_include_ip_address smtp boolean&!! true
Exim normally includes both the host name and the IP address in the key it
constructs for indexing retry data after a temporary delivery failure. This
means that when one of several IP addresses for a host is failing, it gets
However, in some dialup environments hosts are assigned a different IP address
each time they connect. In this situation the use of the IP address as part of
the retry key leads to undesirable behaviour. Setting this option false causes
-Exim to use only the host name. This should normally be done on a separate
-instance of the &(smtp)& transport, set up specially to handle the dialup
-hosts.
+Exim to use only the host name.
+Since it is expanded it can be made to depend on the host or domain.
.option serialize_hosts smtp "host list&!!" unset
in clear.
-.option tls_try_verify_hosts smtp "host list&!! unset
+.option tls_try_verify_hosts smtp "host list&!!" *
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
This option gives a list of hosts for which, on encrypted connections,
certificate verification will be tried but need not succeed.
The &%tls_verify_certificates%& option must also be set.
+Note that unless the host is in this list
+TLS connections will be denied to hosts using self-signed certificates
+when &%tls_verify_certificates%& is matched.
+The &$tls_out_certificate_verified$& variable is set when
+certificate verification succeeds.
-.option tls_verify_certificates smtp string&!! unset
+.option tls_verify_cert_hostnames smtp "host list&!!" *
+.cindex "TLS" "server certificate hostname verification"
+.cindex "certificate" "verification of server"
+This option give a list of hosts for which,
+while verifying the server certificate,
+checks will be included on the host name
+(note that this will generally be the result of a DNS MX lookup)
+versus Subject and Subject-Alternate-Name fields. Wildcard names are permitted
+limited to being the initial component of a 3-or-more component FQDN.
+
+There is no equivalent checking on client certificates.
+
+
+.option tls_verify_certificates smtp string&!! system
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
.vindex "&$host$&"
.vindex "&$host_address$&"
-The value of this option must be the absolute path to a file containing
-permitted server certificates, for use when setting up an encrypted connection.
-Alternatively, if you are using OpenSSL, you can set
-&%tls_verify_certificates%& to the name of a directory containing certificate
-files. This does not work with GnuTLS; the option must be set to the name of a
-single file if you are using GnuTLS. The values of &$host$& and
+The value of this option must be either the
+word "system"
+or the absolute path to
+a file or directory containing permitted certificates for servers,
+for use when setting up an encrypted connection.
+
+The "system" value for the option will use a location compiled into the SSL library.
+This is not available for GnuTLS versions preceding 3.0.20; a value of "system"
+is taken as empty and an explicit location
+must be specified.
+
+The use of a directory for the option value is not avilable for GnuTLS versions
+preceding 3.3.6 and a single file must be used.
+
+With OpenSSL the certificates specified
+explicitly
+either by file or directory
+are added to those given by the system default location.
+
+The values of &$host$& and
&$host_address$& are set to the name and address of the server during the
expansion of this option. See chapter &<<CHAPTLS>>& for details of TLS.
For back-compatability,
if neither tls_verify_hosts nor tls_try_verify_hosts are set
+(a single-colon empty list counts as being set)
and certificate verification fails the TLS connection is closed.
-.option tls_verify_hosts smtp "host list&!! unset
+.option tls_verify_hosts smtp "host list&!!" unset
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
This option gives a list of hosts for which. on encrypted connections,
.scindex IIDdcotauth2 "authenticators" "&(dovecot)&"
This authenticator is an interface to the authentication facility of the
Dovecot POP/IMAP server, which can support a number of authentication methods.
+Note that Dovecot must be configured to use auth-client not auth-userdb.
If you are using Dovecot to authenticate POP/IMAP clients, it might be helpful
to use the same mechanisms for SMTP authentication. This is a server
authenticator only. There is only one option:
driver = dovecot
public_name = PLAIN
server_socket = /var/run/dovecot/auth-client
- server_set_id = $auth2
+ server_set_id = $auth1
dovecot_ntlm:
driver = dovecot
There are some differences in usage when using GnuTLS instead of OpenSSL:
.ilist
-The &%tls_verify_certificates%& option must contain the name of a file, not the
-name of a directory (for OpenSSL it can be either).
+The &%tls_verify_certificates%& option
+cannot be the path of a directory
+for GnuTLS versions before 3.3.6
+(for later versions, or OpenSSL, it can be either).
.next
The default value for &%tls_dhparam%& differs for historical reasons.
.next
as part of the &[gnutls_priority_init]& function. This is very similar to the
ciphersuite specification in OpenSSL.
-The &%tls_require_ciphers%& option is treated as the GnuTLS priority string.
+The &%tls_require_ciphers%& option is treated as the GnuTLS priority string
+and controls both protocols and ciphers.
The &%tls_require_ciphers%& option is available both as an global option,
controlling how Exim behaves as a server, and also as an option of the
&url(http://www.gnutls.org/manual/gnutls.html#Listing-the-ciphersuites-in-a-priority-string, then the example code)
on that site can be used to test a given string.
+For example:
+.code
+# Disable older versions of protocols
+tls_require_ciphers = NORMAL:%LATEST_RECORD_VERSION:-VERS-SSL3.0
+.endd
+
Prior to Exim 4.80, an older API of GnuTLS was used, and Exim supported three
additional options, "&%gnutls_require_kx%&", "&%gnutls_require_mac%&" and
"&%gnutls_require_protocols%&". &%tls_require_ciphers%& was an Exim list.
These options are, in fact, expanded strings, so you can make them depend on
the identity of the client that is connected if you wish. The first file
contains the server's X509 certificate, and the second contains the private key
-that goes with it. These files need to be readable by the Exim user, and must
-always be given as full path names. They can be the same file if both the
+that goes with it. These files need to be
+PEM format and readable by the Exim user, and must
+always be given as full path names.
+The key must not be password-protected.
+They can be the same file if both the
certificate and the key are contained within it. If &%tls_privatekey%& is not
set, or if its expansion is forced to fail or results in an empty string, this
is assumed to be the case. The certificate file may also contain intermediate
apply to all TLS connections. For any host that matches one of these options,
Exim requests a certificate as part of the setup of the TLS session. The
contents of the certificate are verified by comparing it with a list of
-expected certificates. These must be available in a file or,
-for OpenSSL only (not GnuTLS), a directory, identified by
+expected certificates.
+These may be the system default set (depending on library version),
+an explicit file or,
+depending on library version, a directory, identified by
&%tls_verify_certificates%&.
A file can contain multiple certificates, concatenated end to end. If a
.cindex "TLS" "revoked certificates"
.cindex "revocation list"
.cindex "certificate" "revocation list"
+.cindex "OCSP" "stapling"
Certificate issuing authorities issue Certificate Revocation Lists (CRLs) when
certificates are revoked. If you have such a list, you can pass it to an Exim
server using the global option called &%tls_crl%& and to an Exim client using
an identically named option for the &(smtp)& transport. In each case, the value
of the option is expanded and must then be the name of a file that contains a
CRL in PEM format.
+The downside is that clients have to periodically re-download a potentially huge
+file from every certificate authority they know of.
+
+The way with most moving parts at query time is Online Certificate
+Status Protocol (OCSP), where the client verifies the certificate
+against an OCSP server run by the CA. This lets the CA track all
+usage of the certs. It requires running software with access to the
+private key of the CA, to sign the responses to the OCSP queries. OCSP
+is based on HTTP and can be proxied accordingly.
+
+The only widespread OCSP server implementation (known to this writer)
+comes as part of OpenSSL and aborts on an invalid request, such as
+connecting to the port and then disconnecting. This requires
+re-entering the passphrase each time some random client does this.
+
+The third way is OCSP Stapling; in this, the server using a certificate
+issued by the CA periodically requests an OCSP proof of validity from
+the OCSP server, then serves it up inline as part of the TLS
+negotiation. This approach adds no extra round trips, does not let the
+CA track users, scales well with number of certs issued by the CA and is
+resilient to temporary OCSP server failures, as long as the server
+starts retrying to fetch an OCSP proof some time before its current
+proof expires. The downside is that it requires server support.
+
+Unless Exim is built with the support disabled,
+or with GnuTLS earlier than version 3.1.3,
+support for OCSP stapling is included.
+
+There is a global option called &%tls_ocsp_file%&.
+The file specified therein is expected to be in DER format, and contain
+an OCSP proof. Exim will serve it as part of the TLS handshake. This
+option will be re-expanded for SNI, if the &%tls_certificate%& option
+contains &`tls_in_sni`&, as per other TLS options.
+
+Exim does not at this time implement any support for fetching a new OCSP
+proof. The burden is on the administrator to handle this, outside of
+Exim. The file specified should be replaced atomically, so that the
+contents are always valid. Exim will expand the &%tls_ocsp_file%& option
+on each connection, so a new file will be handled transparently on the
+next connection.
+
+When built with OpenSSL Exim will check for a valid next update timestamp
+in the OCSP proof; if not present, or if the proof has expired, it will be
+ignored.
+
+For the client to be able to verify the stapled OCSP the server must
+also supply, in its stapled information, any intermediate
+certificates for the chain leading to the OCSP proof from the signer
+of the server certificate. There may be zero or one such. These
+intermediate certificates should be added to the server OCSP stapling
+file named by &%tls_ocsp_file%&.
+
+Note that the proof only covers the terminal server certificate,
+not any of the chain from CA to it.
+
+There is no current way to staple a proof for a client certificate.
+
+.code
+ A helper script "ocsp_fetch.pl" for fetching a proof from a CA
+ OCSP server is supplied. The server URL may be included in the
+ server certificate, if the CA is helpful.
+
+ One failure mode seen was the OCSP Signer cert expiring before the end
+ of validity of the OCSP proof. The checking done by Exim/OpenSSL
+ noted this as invalid overall, but the re-fetch script did not.
+.endd
+
+
.section "Configuring an Exim client to use TLS" "SECID185"
&%tls_verify_hosts%& or &%tls_try_verify_hosts%& matches the client.
If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it
+specifies a collection of expected server certificates.
+These may be the system default set (depeding on library version),
+a file or,
+depnding on liibrary version, a directory,
must name a file or,
-for OpenSSL only (not GnuTLS), a directory, that contains a collection of
-expected server certificates. The client verifies the server's certificate
+for OpenSSL only (not GnuTLS), a directory.
+The client verifies the server's certificate
against this collection, taking into account any revoked certificates that are
in the list defined by &%tls_crl%&.
Failure to verify fails the TLS connection unless either of the
certificate verification to the listed servers. Verification either must
or need not succeed respectively.
+The &(smtp)& transport has two OCSP-related options:
+&%hosts_require_ocsp%&; a host-list for which a Certificate Status
+is requested and required for the connection to proceed. The default
+value is empty.
+&%hosts_request_ocsp%&; a host-list for which (additionally)
+a Certificate Status is requested (but not necessarily verified). The default
+value is "*" meaning that requests are made unless configured
+otherwise.
+
+The host(s) should also be in &%hosts_require_tls%&, and
+&%tls_verify_certificates%& configured for the transport,
+for OCSP to be relevant.
+
If
&%tls_require_ciphers%& is set on the &(smtp)& transport, it must contain a
list of permitted cipher suites. If either of these checks fails, delivery to
.next
.vindex "&%tls_verify_certificates%&"
&%tls_verify_certificates%&
+.next
+.vindex "&%tls_ocsp_file%&"
+&%tls_verify_certificates%&
.endlist
Great care should be taken to deal with matters of case, various injection
.cindex "SMTP" "connection, ACL for"
.cindex "non-SMTP messages" "ACLs for"
.cindex "MIME content scanning" "ACL for"
+.cindex "PRDR" "ACL for"
.table2 140pt
.irow &%acl_not_smtp%& "ACL for non-SMTP messages"
.irow &%acl_smtp_auth%& "ACL for AUTH"
.irow &%acl_smtp_connect%& "ACL for start of SMTP connection"
.irow &%acl_smtp_data%& "ACL after DATA is complete"
+.irow &%acl_smtp_data_prdr%& "ACL for each recipient, after DATA is complete"
.irow &%acl_smtp_etrn%& "ACL for ETRN"
.irow &%acl_smtp_expn%& "ACL for EXPN"
.irow &%acl_smtp_helo%& "ACL for HELO or EHLO"
and try again later, but that is their problem, though it does waste some of
your resources.
-The &%acl_smtp_data%& ACL is run after both the &%acl_smtp_dkim%& and
-the &%acl_smtp_mime%& ACLs.
+The &%acl_smtp_data%& ACL is run after
+the &%acl_smtp_data_prdr%&,
+the &%acl_smtp_dkim%&
+and the &%acl_smtp_mime%& ACLs.
.section "The SMTP DKIM ACL" "SECTDKIMACL"
The &%acl_smtp_dkim%& ACL is available only when Exim is compiled with DKIM support
This ACL is evaluated after &%acl_smtp_dkim%& but before &%acl_smtp_data%&.
+.section "The SMTP PRDR ACL" "SECTPRDRACL"
+.cindex "PRDR" "ACL for"
+.oindex "&%prdr_enable%&"
+The &%acl_smtp_data_prdr%& ACL is available only when Exim is compiled
+with PRDR support enabled (which is the default).
+It becomes active only when the PRDR feature is negotiated between
+client and server for a message, and more than one recipient
+has been accepted.
+
+The ACL test specfied by &%acl_smtp_data_prdr%& happens after a message
+has been recieved, and is executed once for each recipient of the message
+with &$local_part$& and &$domain$& valid.
+The test may accept, defer or deny for inividual recipients.
+The &%acl_smtp_data%& will still be called after this ACL and
+can reject the message overall, even if this ACL has accepted it
+for some or all recipients.
+
+PRDR may be used to support per-user content filtering. Without it
+one must defer any recipient after the first that has a different
+content-filter configuration. With PRDR, the RCPT-time check
+for this can be disabled when the MAIL-time $smtp_command included
+"PRDR". Any required difference in behaviour of the main DATA-time
+ACL should however depend on the PRDR-time ACL having run, as Exim
+will avoid doing so in some situations (eg. single-recipient mails).
+
+See also the &%prdr_enable%& global option
+and the &%hosts_try_prdr%& smtp transport option.
+
+This ACL is evaluated after &%acl_smtp_dkim%& but before &%acl_smtp_data%&.
+If the ACL is not defined, processing completes as if
+the feature was not requested by the client.
+
.section "The QUIT ACL" "SECTQUITACL"
.cindex "QUIT, ACL for"
The ACL for the SMTP QUIT command is anomalous, in that the outcome of the ACL
response.
.vindex "&$acl_verify_message$&"
+.new
+For ACLs that are called by an &%acl =%& ACL condition, the message is
+stored in &$acl_verify_message$&, from which the calling ACL may use it.
+.wen
+
If &%message%& is used on a statement that verifies an address, the message
specified overrides any message that is generated by the verification process.
However, the original message is available in the variable
and $acl_narg is set to the count of values.
Previous values of these variables are restored after the call returns.
The name and values are expanded separately.
+Note that spaces in complex expansions which are used as arguments
+will act as argument separators.
If the nested &%acl%& returns &"drop"& and the outer condition denies access,
the connection is dropped. If it returns &"discard"&, the verb must be
send email. Details of how this works are given in section
&<<SECTverifyCSA>>&.
-.new
.vitem &*verify&~=&~header_names_ascii*&
.cindex "&%verify%& ACL condition"
.cindex "&ACL;" "verifying header names only ASCII"
Exim itself will handle headers with non-ASCII characters, but it can cause
problems for downstream applications, so this option will allow their
detection and rejection in the DATA ACL's.
-.wen
.vitem &*verify&~=&~header_sender/*&<&'options'&>
.cindex "&%verify%& ACL condition"
specialized interfaces for &"daemon"& type virus scanners, which are resident
in memory and thus are much faster.
+A timeout of 2 minutes is applied to a scanner call (by default);
+if it expires then a defer action is taken.
.oindex "&%av_scanner%&"
-You can set the &%av_scanner%& option in first part of the Exim configuration
-file to specify which scanner to use, together with any additional options that
+You can set the &%av_scanner%& option in the main part of the configuration
+to specify which scanner to use, together with any additional options that
are needed. The basic syntax is as follows:
.display
&`av_scanner = <`&&'scanner-type'&&`>:<`&&'option1'&&`>:<`&&'option2'&&`>:[...]`&
The following scanner types are supported in this release:
.vlist
+.vitem &%avast%&
+.cindex "virus scanners" "avast"
+This is the scanner daemon of Avast. It has been tested with Avast Core
+Security (currenty at version 1.1.7).
+You can get a trial version at &url(http://www.avast.com) or for Linux
+at &url(http://www.avast.com/linux-server-antivirus).
+This scanner type takes one option,
+which can be either a full path to a UNIX socket,
+or host and port specifiers separated by white space.
+The host may be a name or an IP address; the port is either a
+single number or a pair of numbers with a dash between.
+Any further options are given, on separate lines,
+to the daemon as options before the main scan command.
+For example:
+.code
+av_scanner = avast:/var/run/avast/scan.sock:FLAGS -fullfiles:SENSITIVITY -pup
+av_scanner = avast:192.168.2.22 5036
+.endd
+If you omit the argument, the default path
+&_/var/run/avast/scan.sock_&
+is used.
+If you use a remote host,
+you need to make Exim's spool directory available to it,
+as the scanner is passed a file path, not file contents.
+For information about available commands and their options you may use
+.code
+$ socat UNIX:/var/run/avast/scan.sock STDIO:
+ FLAGS
+ SENSITIVITY
+ PACK
+.endd
+
+
.vitem &%aveserver%&
.cindex "virus scanners" "Kaspersky"
This is the scanner daemon of Kaspersky Version 5. You can get a trial version
.endd
.vitem &%drweb%&
.cindex "virus scanners" "DrWeb"
-The DrWeb daemon scanner (&url(http://www.sald.com/)) interface takes one
-argument, either a full path to a UNIX socket, or an IP address and port
-separated by white space, as in these examples:
+The DrWeb daemon scanner (&url(http://www.sald.com/)) interface
+takes one option,
+either a full path to a UNIX socket,
+or host and port specifiers separated by white space.
+The host may be a name or an IP address; the port is either a
+single number or a pair of numbers with a dash between.
+For example:
.code
av_scanner = drweb:/var/run/drwebd.sock
av_scanner = drweb:192.168.2.20 31337
message.
The &%malware%& condition takes a right-hand argument that is expanded before
-use. It can then be one of
+use and taken as a list, slash-separated by default.
+The first element can then be one of
.ilist
&"true"&, &"*"&, or &"1"&, in which case the message is scanned for viruses.
A regular expression, in which case the message is scanned for viruses. The
condition succeeds if a virus is found and its name matches the regular
expression. This allows you to take special actions on certain types of virus.
+Note that &"/"& characters in the RE must be doubled due to the list-processing,
+unless the separator is changed (in the usual way).
.endlist
-You can append &`/defer_ok`& to the &%malware%& condition to accept messages
-even if there is a problem with the virus scanner. Otherwise, such a problem
-causes the ACL to defer.
+You can append a &`defer_ok`& element to the &%malware%& argument list to accept
+messages even if there is a problem with the virus scanner.
+Otherwise, such a problem causes the ACL to defer.
+
+You can append a &`tmo=<val>`& element to the &%malware%& argument list to
+specify a non-default timeout. The default is two minutes.
+For example:
+.code
+malware = * / defer_ok / tmo=10s
+.endd
+A timeout causes the ACL to defer.
.vindex "&$malware_name$&"
When a virus is found, the condition sets up an expansion variable called
Multiple &%headers_remove%& options for a single router or transport can be
specified; the arguments will append to a single header-names list.
Each item is separately expanded.
+Note that colons in complex expansions which are used to
+form all or part of a &%headers_remove%& list
+will act as list separators.
When &%headers_add%& or &%headers_remove%& is specified on a router,
items are expanded at routing time,
The third item is used to introduce any text from pipe transports that is to be
returned to the sender. It is omitted if there is no such text.
.next
-The fourth item is used to introduce the copy of the message that is returned
-as part of the error report.
-.next
-The fifth item is added after the fourth one if the returned message is
-truncated because it is bigger than &%return_size_limit%&.
-.next
-The sixth item is added after the copy of the original message.
+The fourth, fifth and sixth items will be ignored and may be empty.
+The fields exist for back-compatibility
.endlist
The default state (&%bounce_message_file%& unset) is equivalent to the
&` smtp_protocol_error `& SMTP protocol errors
&` smtp_syntax_error `& SMTP syntax errors
&` subject `& contents of &'Subject:'& on <= lines
-&` tls_certificate_verified `& certificate verification status
+&`*tls_certificate_verified `& certificate verification status
&`*tls_cipher `& TLS cipher suite on <= and => lines
&` tls_peerdn `& TLS peer DN on <= and => lines
&` tls_sni `& TLS SNI on <= lines
.code
exim -bp
.endd
-.new
The &*-C*& option is used to specify an alternate &_exim.conf_& which might
contain alternate exim configuration the queue management might be using.
-.wen
to obtain a queue listing, and then greps the output to select messages
that match given criteria. The following selection options are available:
The input files can be in Exim log format or syslog format.
If a matching log line is not associated with a specific message, it is
included in &'exigrep'&'s output without any additional lines. The usage is:
+.new
.display
-&`exigrep [-t<`&&'n'&&`>] [-I] [-l] [-v] <`&&'pattern'&&`> [<`&&'log file'&&`>] ...`&
+&`exigrep [-t<`&&'n'&&`>] [-I] [-l] [-M] [-v] <`&&'pattern'&&`> [<`&&'log file'&&`>] ...`&
.endd
+.wen
If no log file names are given on the command line, the standard input is read.
The &%-t%& argument specifies a number of seconds. It adds an additional
The &%-v%& option inverts the matching condition. That is, a line is selected
if it does &'not'& match the pattern.
+.new
+The &%-M%& options means &"related messages"&. &'exigrep'& will show messages
+that are generated as a result/response to a message that &'exigrep'& matched
+normally.
+
+Example of &%-M%&:
+user_a sends a message to user_b, which generates a bounce back to user_b. If
+&'exigrep'& is used to search for &"user_a"&, only the first message will be
+displayed. But if &'exigrep'& is used to search for &"user_b"&, the first and
+the second (bounce) message will be displayed. Using &%-M%& with &'exigrep'&
+when searching for &"user_a"& will show both messages since the bounce is
+&"related"& to or a &"result"& of the first message that was found by the
+search term.
+.wen
+
If the location of a &'zcat'& command is known from the definition of
ZCAT_COMMAND in &_Local/Makefile_&, &'exigrep'& automatically passes any file
whose name ends in COMPRESS_SUFFIX through &'zcat'& as it searches it.
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