.cindex "distribution" "signing details"
.cindex "distribution" "public key"
.cindex "public key for signed distribution"
-The distributions are currently signed with Nigel Metheringham's GPG key. The
-corresponding public key is available from a number of keyservers, and there is
-also a copy in the file &_nigel-pubkey.asc_&. The signatures for the tar bundles are
-in:
+.new
+The distributions will be PGP signed by an individual key of the Release
+Coordinator. This key will have a uid containing an email address in the
+&'exim.org'& domain and will have signatures from other people, including
+other Exim maintainers. We expect that the key will be in the "strong set" of
+PGP keys. There should be a trust path to that key from Nigel Metheringham's
+PGP key, a version of which can be found in the release directory in the file
+&_nigel-pubkey.asc_&. All keys used will be available in public keyserver pools,
+such as &'pool.sks-keyservers.net'&.
+
+At time of last update, releases were being made by Phil Pennock and signed with
+key &'0x403043153903637F'&, although that key is expected to be replaced in 2013.
+A trust path from Nigel's key to Phil's can be observed at
+&url(https://www.security.spodhuis.org/exim-trustpath).
+.wen
+
+The signatures for the tar bundles are in:
.display
&_exim-n.nn.tar.gz.asc_&
&_exim-n.nn.tar.bz2.asc_&
&%verify_recipient%&, which independently control the use of the router for
sender and recipient verification. You can set these options directly if
you want a router to be used for only one type of verification.
+Note that cutthrough delivery is classed as a recipient verification
+for this purpose.
.next
If the &%address_test%& option is set false, the router is skipped when Exim is
run with the &%-bt%& option to test an address routing. This can be helpful
.next
Routers can be designated for use only when verifying an address, as
opposed to routing it for delivery. The &%verify_only%& option controls this.
+Again, cutthrough delibery counts as a verification.
.next
Individual routers can be explicitly skipped when running the routers to
check an address given in the SMTP EXPN command (see the &%expn%& option).
the subnet 192.168.1.0/24, and from all hosts in &'friendly.domain.example'&.
All other connections are denied. The daemon name used by &'tcpwrappers'&
can be changed at build time by setting TCP_WRAPPERS_DAEMON_NAME in
-in &_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
+&_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
configure file. Consult the &'tcpwrappers'& documentation for
further details.
.oindex "&%-bm%&"
.cindex "local message reception"
This option runs an Exim receiving process that accepts an incoming,
-locally-generated message on the current input. The recipients are given as the
+locally-generated message on the standard input. The recipients are given as the
command arguments (except when &%-t%& is also present &-- see below). Each
argument can be a comma-separated list of RFC 2822 addresses. This is the
default option for selecting the overall action of an Exim call; it is assumed
Provided
this error message is successfully sent, the Exim receiving process
exits with a return code of zero. If not, the return code is 2 if the problem
-is that the original message has no recipients, or 1 any other error. This is
-the default &%-oe%&&'x'& option if Exim is called as &'rmail'&.
+is that the original message has no recipients, or 1 for any other error.
+This is the default &%-oe%&&'x'& option if Exim is called as &'rmail'&.
.vitem &%-oem%&
.oindex "&%-oem%&"
.vitem &%-Tqt%&&~<&'times'&>
.oindex "&%-Tqt%&"
-This an option that is exclusively for use by the Exim testing suite. It is not
+This is an option that is exclusively for use by the Exim testing suite. It is not
recognized when Exim is run normally. It allows for the setting up of explicit
&"queue times"& so that various warning/retry features can be tested.
The authorization code can be &"Y"& for yes, &"N"& for no, &"X"& for explicit
authorization required but absent, or &"?"& for unknown.
+.cindex "A+" "in &(dnsdb)& lookup"
+The pseudo-type A+ performs an A6 lookup (if configured) followed by an AAAA
+and then an A lookup. All results are returned; defer processing
+(see below) is handled separately for each lookup. Example:
+.code
+${lookup dnsdb {>; a+=$sender_helo_name}}
+.endd
+
.section "Multiple dnsdb lookups" "SECID67"
In the previous sections, &(dnsdb)& lookups for a single domain are described.
There are several types of pattern that require Exim to know the name of the
remote host. These are either wildcard patterns or lookups by name. (If a
complete hostname is given without any wildcarding, it is used to find an IP
-address to match against, as described in the section &<<SECThoslispatip>>&
+address to match against, as described in section &<<SECThoslispatip>>&
above.)
If the remote host name is not already known when Exim encounters one of these
operator.
If the query contains a reference to &$sender_host_name$&, Exim automatically
-looks up the host name if has not already done so. (See section
+looks up the host name if it has not already done so. (See section
&<<SECThoslispatnam>>& for comments on finding host names.)
Historical note: prior to release 4.30, Exim would always attempt to find a
surrounding the colons is ignored. For example:
.code
aol.com: spammer1 : spammer2 : ^[0-9]+$ :
-spammer3 : spammer4
+ spammer3 : spammer4
.endd
As in all colon-separated lists in Exim, a colon can be included in an item by
doubling.
command does not succeed. If both strings are omitted, the result is contents
of the standard output/error on success, and nothing on failure.
+.vindex "&$run_in_acl$&"
+The standard output/error of the command is put in the variable &$value$&.
+In this ACL example, the output of a command is logged for the admin to
+troubleshoot:
+.code
+warn condition = ${run{/usr/bin/id}{yes}{no}}
+ log_message = Output of id: $value
+.endd
+If the command requires shell idioms, such as the > redirect operator, the
+shell must be invoked directly, such as with:
+.code
+${run{/bin/bash -c "/usr/bin/id >/tmp/id"}{yes}{yes}}
+.endd
+
.vindex "&$runrc$&"
The return code from the command is put in the variable &$runrc$&, and this
remains set afterwards, so in a filter file you can do things like this:
The string is interpreted as a list and the number of items is returned.
-.vitem &*${listnamed:*&<&'name'&>&*}*&&~and&~&*${list_*&<&'type'&>&*name'&>&*}*&
+.vitem &*${listnamed:*&<&'name'&>&*}*&&~and&~&*${list_*&<&'type'&>&*name*&>&*}*&
.cindex "expansion" "named list"
.cindex "&%listnamed%& expansion item"
The name is interpreted as a named list and the content of the list is returned,
be terminated by colon or white space, because it may contain a wide variety of
characters. Note also that braces must &'not'& be used.
+.vitem &$headers_added$&
+.vindex "&$headers_added$&"
+Within an ACL this variable contains the headers added so far by
+the ACL modifier add_header (section &<<SECTaddheadacl>>&).
+The headers are a newline-separated list.
+
.vitem &$home$&
.vindex "&$home$&"
When the &%check_local_user%& option is set for a router, the user's home
.endd
To specify listening on the default port on specific interfaces only:
.code
-local_interfaces = 192.168.34.67 : 192.168.34.67
+local_interfaces = 10.0.0.67 : 192.168.34.67
.endd
&*Warning*&: Such a setting excludes listening on the loopback interfaces.
.section "TLS" "SECID108"
.table2
.row &%gnutls_compat_mode%& "use GnuTLS compatibility mode"
-.new
.row &%gnutls_enable_pkcs11%& "allow GnuTLS to autoload PKCS11 modules"
-.wen
.row &%openssl_options%& "adjust OpenSSL compatibility options"
.row &%tls_advertise_hosts%& "advertise TLS to these hosts"
.row &%tls_certificate%& "location of server certificate"
.row &%dns_ipv4_lookup%& "only v4 lookup for these domains"
.row &%dns_retrans%& "parameter for resolver"
.row &%dns_retry%& "parameter for resolver"
-.new
.row &%dns_use_dnssec%& "parameter for resolver"
-.wen
.row &%dns_use_edns0%& "parameter for resolver"
.row &%hold_domains%& "hold delivery for these domains"
.row &%local_interfaces%& "for routing checks"
.option accept_8bitmime main boolean true
.cindex "8BITMIME"
.cindex "8-bit characters"
+.cindex "log" "selectors"
+.cindex "log" "8BITMIME"
This option causes Exim to send 8BITMIME in its response to an SMTP
EHLO command, and to accept the BODY= parameter on MAIL commands.
However, though Exim is 8-bit clean, it is not a protocol converter, and it
&url(http://cr.yp.to/smtp/8bitmime.html)
.endd
+To log received 8BITMIME status use
+.code
+log_selector = +8bitmime
+.endd
+
.option acl_not_smtp main string&!! unset
.cindex "&ACL;" "for non-SMTP messages"
.cindex "non-SMTP messages" "ACLs for"
.cindex "EXPN" "with &%verify_only%&"
.oindex "&%-bv%&"
.cindex "router" "used only when verifying"
-If this option is set, the router is used only when verifying an address or
+If this option is set, the router is used only when verifying an address,
+delivering in cutthrough mode or
testing with the &%-bv%& option, not when actually doing a delivery, testing
with the &%-bt%& option, or running the SMTP EXPN command. It can be further
restricted to verifying only senders or recipients by means of
.option verify_recipient routers&!? boolean true
If this option is false, the router is skipped when verifying recipient
-addresses
+addresses,
+delivering in cutthrough mode
or testing recipient verification using &%-bv%&.
See section &<<SECTrouprecon>>& for a list of the order in which preconditions
are evaluated.
.option transport_filter_timeout transports time 5m
.cindex "transport" "filter, timeout"
-When Exim is reading the output of a transport filter, it a applies a timeout
+When Exim is reading the output of a transport filter, it applies a timeout
that can be set by this option. Exceeding the timeout is normally treated as a
temporary delivery failure. However, if a transport filter is used with a
&(pipe)& transport, a timeout in the transport filter is treated in the same
.section "The not-QUIT ACL" "SECTNOTQUITACL"
.vindex &$acl_smtp_notquit$&
The not-QUIT ACL, specified by &%acl_smtp_notquit%&, is run in most cases when
-an SMTP session ends without sending QUIT. However, when Exim itself is is bad
+an SMTP session ends without sending QUIT. However, when Exim itself is in bad
trouble, such as being unable to write to its log files, this ACL is not run,
because it might try to do things (such as write to log files) that make the
situation even worse.
If &%log_message%& is not present, a &%warn%& verb just checks its conditions
and obeys any &"immediate"& modifiers (such as &%control%&, &%set%&,
-&%logwrite%&, and &%add_header%&) that appear before the first failing
-condition. There is more about adding header lines in section
+&%logwrite%&, &%add_header%&, and &%remove_header%&) that appear before the
+first failing condition. There is more about adding header lines in section
&<<SECTaddheadacl>>&.
If any condition on a &%warn%& statement cannot be completed (that is, there is
warning is generated. The &%control%& modifier affects the way an incoming
message is handled.
-The positioning of the modifiers in an ACL statement important, because the
+The positioning of the modifiers in an ACL statement is important, because the
processing of a verb ceases as soon as its outcome is known. Only those
modifiers that have already been encountered will take effect. For example,
consider this use of the &%message%& modifier:
.vitem &*delay*&&~=&~<&'time'&>
.cindex "&%delay%& ACL modifier"
.oindex "&%-bh%&"
-This modifier may appear in any ACL. It causes Exim to wait for the time
-interval before proceeding. However, when testing Exim using the &%-bh%&
-option, the delay is not actually imposed (an appropriate message is output
-instead). The time is given in the usual Exim notation, and the delay happens
-as soon as the modifier is processed. In an SMTP session, pending output is
-flushed before the delay is imposed.
+This modifier may appear in any ACL except notquit. It causes Exim to wait for
+the time interval before proceeding. However, when testing Exim using the
+&%-bh%& option, the delay is not actually imposed (an appropriate message is
+output instead). The time is given in the usual Exim notation, and the delay
+happens as soon as the modifier is processed. In an SMTP session, pending
+output is flushed before the delay is imposed.
Like &%control%&, &%delay%& can be used with &%accept%& or &%deny%&, for
example:
effect.
+.vitem &*remove_header*&&~=&~<&'text'&>
+This modifier specifies one or more header names in a colon-separated list
+ that are to be removed from an incoming message, assuming, of course, that
+the message is ultimately accepted. For details, see section &<<SECTremoveheadacl>>&.
+
+
.vitem &*set*&&~<&'acl_name'&>&~=&~<&'value'&>
.cindex "&%set%& ACL modifier"
This modifier puts a value into one of the ACL variables (see section
.new
.vitem &*control&~=&~cutthrough_delivery*&
.cindex "&ACL;" "cutthrough routing"
+.cindex "cutthrough" "requesting"
This option requests delivery be attempted while the item is being received.
It is usable in the RCPT ACL and valid only for single-recipient mails forwarded
from one SMTP connection to another. If a recipient-verify callout connection is
requested in the same ACL it is held open and used for the data, otherwise one is made
-after the ACL completes.
+after the ACL completes. Note that routers are used in verify mode.
Should the ultimate destination system positively accept or reject the mail,
a corresponding indication is given to the source system and nothing is queued.
.new
-.vitem &*control&~=&~dscp/*&<&'value'&>
-.cindex "&ACL;" "setting DSCP value"
-.cindex "DSCP" "inbound"
-This option causes the DSCP value associated with the socket for the inbound
-connection to be adjusted to a given value, given as one of a number of fixed
-strings or to numeric value.
-The &%-bI:dscp%& option may be used to ask Exim which names it knows of.
-Common values include &`throughput`&, &`mincost`&, and on newer systems
-&`ef`&, &`af41`&, etc. Numeric values may be in the range 0 to 0x3F.
-
-The outbound packets from Exim will be marked with this value in the header
-(for IPv4, the TOS field; for IPv6, the TCLASS field); there is no guarantee
-that these values will have any effect, not be stripped by networking
-equipment, or do much of anything without cooperation with your Network
-Engineer and those of all network operators between the source and destination.
-.wen
-
-
.vitem &*control&~=&~debug/*&<&'options'&>
.cindex "&ACL;" "enabling debug logging"
.cindex "debugging" "enabling from an ACL"
control = debug/opts=+expand+acl
control = debug/tag=.$message_exim_id/opts=+expand
.endd
+.wen
+
+
+.new
+.vitem &*control&~=&~dkim_disable_verify*&
+.cindex "disable DKIM verify"
+.cindex "DKIM" "disable verify"
+This control turns off DKIM verification processing entirely. For details on
+the operation and configuration of DKIM, see chapter &<<CHID12>>&.
+.wen
+
+
+.new
+.vitem &*control&~=&~dscp/*&<&'value'&>
+.cindex "&ACL;" "setting DSCP value"
+.cindex "DSCP" "inbound"
+This option causes the DSCP value associated with the socket for the inbound
+connection to be adjusted to a given value, given as one of a number of fixed
+strings or to numeric value.
+The &%-bI:dscp%& option may be used to ask Exim which names it knows of.
+Common values include &`throughput`&, &`mincost`&, and on newer systems
+&`ef`&, &`af41`&, etc. Numeric values may be in the range 0 to 0x3F.
+
+The outbound packets from Exim will be marked with this value in the header
+(for IPv4, the TOS field; for IPv6, the TCLASS field); there is no guarantee
+that these values will have any effect, not be stripped by networking
+equipment, or do much of anything without cooperation with your Network
+Engineer and those of all network operators between the source and destination.
+.wen
.vitem &*control&~=&~enforce_sync*& &&&
.section "Adding header lines in ACLs" "SECTaddheadacl"
.cindex "header lines" "adding in an ACL"
.cindex "header lines" "position of added lines"
-.cindex "&%message%& ACL modifier"
+.cindex "&%add_header%& ACL modifier"
The &%add_header%& modifier can be used to add one or more extra header lines
to an incoming message, as in this example:
.code
any ACL verb, including &%deny%& (though this is potentially useful only in a
RCPT ACL).
-If the data for the &%add_header%& modifier contains one or more newlines that
+Leading and trailing newlines are removed from
+the data for the &%add_header%& modifier; if it then
+contains one or more newlines that
are not followed by a space or a tab, it is assumed to contain multiple header
lines. Each one is checked for valid syntax; &`X-ACL-Warn:`& is added to the
front of any line that is not a valid header line.
are included in the entry that is written to the reject log.
.cindex "header lines" "added; visibility of"
-Header lines are not visible in string expansions until they are added to the
+Header lines are not visible in string expansions
+of message headers
+until they are added to the
message. It follows that header lines defined in the MAIL, RCPT, and predata
ACLs are not visible until the DATA ACL and MIME ACLs are run. Similarly,
header lines that are added by the DATA or MIME ACLs are not visible in those
this, you can use ACL variables, as described in section
&<<SECTaclvariables>>&.
-The &%add_header%& modifier acts immediately it is encountered during the
+The list of headers yet to be added is given by the &%$headers_added%& variable.
+
+The &%add_header%& modifier acts immediately as it is encountered during the
processing of an ACL. Notice the difference between these two cases:
.display
&`accept add_header = ADDED: some text`&
+.section "Removing header lines in ACLs" "SECTremoveheadacl"
+.cindex "header lines" "removing in an ACL"
+.cindex "header lines" "position of removed lines"
+.cindex "&%remove_header%& ACL modifier"
+The &%remove_header%& modifier can be used to remove one or more header lines
+from an incoming message, as in this example:
+.code
+warn message = Remove internal headers
+ remove_header = x-route-mail1 : x-route-mail2
+.endd
+The &%remove_header%& modifier is permitted in the MAIL, RCPT, PREDATA, DATA,
+MIME, and non-SMTP ACLs (in other words, those that are concerned with
+receiving a message). The message must ultimately be accepted for
+&%remove_header%& to have any significant effect. You can use &%remove_header%&
+with any ACL verb, including &%deny%&, though this is really not useful for
+any verb that doesn't result in a delivered message.
+
+More than one header can be removed at the same time by using a colon separated
+list of header names. The header matching is case insensitive. Wildcards are
+not permitted, nor is list expansion performed, so you cannot use hostlists to
+create a list of headers, however both connection and message variable expansion
+are performed (&%$acl_c_*%& and &%$acl_m_*%&), illustrated in this example:
+.code
+warn hosts = +internal_hosts
+ set acl_c_ihdrs = x-route-mail1 : x-route-mail2
+warn message = Remove internal headers
+ remove_header = $acl_c_ihdrs
+.endd
+Removed header lines are accumulated during the MAIL, RCPT, and predata ACLs.
+They are removed from the message before processing the DATA and MIME ACLs.
+There is no harm in attempting to remove the same header twice nor is removing
+a non-existent header. Further header lines to be removed may be accumulated
+during the DATA and MIME ACLs, after which they are removed from the message,
+if present. In the case of non-SMTP messages, headers to be removed are
+accumulated during the non-SMTP ACLs, and are removed from the message after
+all the ACLs have run. If a message is rejected after DATA or by the non-SMTP
+ACL, there really is no effect because there is no logging of what headers
+would have been removed.
+
+.cindex "header lines" "removed; visibility of"
+Header lines are not visible in string expansions until the DATA phase when it
+is received. Any header lines removed in the MAIL, RCPT, and predata ACLs are
+not visible in the DATA ACL and MIME ACLs. Similarly, header lines that are
+removed by the DATA or MIME ACLs are still visible in those ACLs. Because of
+this restriction, you cannot use header lines as a way of controlling data
+passed between (for example) the MAIL and RCPT ACLs. If you want to do this,
+you should instead use ACL variables, as described in section
+&<<SECTaclvariables>>&.
+
+The &%remove_header%& modifier acts immediately as it is encountered during the
+processing of an ACL. Notice the difference between these two cases:
+.display
+&`accept remove_header = X-Internal`&
+&` `&<&'some condition'&>
+
+&`accept `&<&'some condition'&>
+&` remove_header = X-Internal`&
+.endd
+In the first case, the header line is always removed, whether or not the
+condition is true. In the second case, the header line is removed only if the
+condition is true. Multiple occurrences of &%remove_header%& may occur in the
+same ACL statement. All those that are encountered before a condition fails
+are honoured.
+
+&*Warning*&: This facility currently applies only to header lines that are
+present during ACL processing. It does NOT remove header lines that are added
+in a system filter or in a router or transport.
+
+
+
+
.section "ACL conditions" "SECTaclconditions"
.cindex "&ACL;" "conditions; list of"
-Some of conditions listed in this section are available only when Exim is
+Some of the conditions listed in this section are available only when Exim is
compiled with the content-scanning extension. They are included here briefly
for completeness. More detailed descriptions can be found in the discussion on
content scanning in chapter &<<CHAPexiscan>>&.
.endd
-.vitem &*hosts&~=&~*&<&'&~host&~list'&>
+.vitem &*hosts&~=&~*&<&'host&~list'&>
.cindex "&%hosts%& ACL condition"
.cindex "host" "ACL checking"
.cindex "&ACL;" "testing the client host"
If the DNS lookup yields both 127.0.0.1 and 127.0.0.2, the condition is
false because 127.0.0.1 matches.
.next
-If &`!==`& or &`!=&&`& is used, the condition is true there is at least one
+If &`!==`& or &`!=&&`& is used, the condition is true if there is at least one
looked up IP address that does not match. Consider:
.code
dnslists = a.b.c!=&0.0.0.1
&`<=`& message arrival
&`=>`& normal message delivery
&`->`& additional address in same delivery
+&`>>`& cutthrough message delivery
&`*>`& delivery suppressed by &%-N%&
&`**`& delivery failed; address bounced
&`==`& delivery deferred; temporary problem
down a single SMTP connection, an asterisk follows the IP address in the log
lines for the second and subsequent messages.
+.cindex "delivery" "cutthrough; logging"
+.cindex "cutthrough" "logging"
+When delivery is done in cutthrough mode it is flagged with &`>>`& and the log
+line precedes the reception line, since cutthrough waits for a possible
+rejection from the destination in case it can reject the sourced item.
+
The generation of a reply message by a filter file gets logged as a
&"delivery"& to the addressee, preceded by &">"&.
The list of optional log items is in the following table, with the default
selection marked by asterisks:
.display
+&` 8bitmime `& received 8BITMIME status
&`*acl_warn_skipped `& skipped &%warn%& statement in ACL
&` address_rewrite `& address rewriting
&` all_parents `& all parents in => lines
More details on each of these items follows:
.ilist
+.cindex "8BITMIME"
+.cindex "log" "8BITMIME"
+&%8bitmime%&: This causes Exim to log any 8BITMIME status of received messages,
+which may help in tracking down interoperability issues with ancient MTAs
+that are not 8bit clean. This is added to the &"<="& line, tagged with
+&`M8S=`& and a value of &`0`&, &`7`& or &`8`&, corresponding to "not given",
+&`7BIT`& and &`8BITMIME`& respectively.
+.next
.cindex "&%warn%& ACL verb" "log when skipping"
&%acl_warn_skipped%&: When an ACL &%warn%& statement is skipped because one of
its conditions cannot be evaluated, a log line to this effect is written if
.vitem &%dkim_status%&
ACL condition that checks a colon-separated list of possible DKIM verification
-results agains the actual result of verification. This is typically used
+results against the actual result of verification. This is typically used
to restrict an ACL verb to a list of verification outcomes, for example:
.code
projects / exim.git / blobdiff