The SIGHUP signal
.cindex "SIGHUP"
.cindex "daemon" "restarting"
+.cindex signal "to reload configuration"
+.cindex daemon "reload configuration"
can be used to cause the daemon to re-execute itself. This should be done
whenever Exim's configuration file, or any file that is incorporated into it by
means of the &%.include%& facility, is changed, and also whenever a new version
&*Warning 2*&: In a host list, you must always use &(net-iplsearch)& so that
the implicit key is the host's IP address rather than its name (see section
&<<SECThoslispatsikey>>&).
+
+.new
+&*Warning 3*&: Do not use an IPv4-mapped IPv6 address for a key; use the
+IPv4, in dotted-quad form. (Exim converts IPv4-mapped IPv6 addresses to this
+notation before executing the lookup.)
+.wen
.next
.new
.cindex lookup json
recently implemented &(iplsearch)& files do require colons in IPv6 keys
(notated using the quoting facility) so as to distinguish them from IPv4 keys.
For this reason, when the lookup type is &(iplsearch)&, IPv6 addresses are
-converted using colons and not dots. In all cases, full, unabbreviated IPv6
+converted using colons and not dots.
+.new
+In all cases except IPv4-mapped IPv6, full, unabbreviated IPv6
addresses are always used.
+The latter are converted to IPv4 addresses, in dotted-quad form.
+.wen
Ideally, it would be nice to tidy up this anomalous situation by changing to
colons in all cases, given that quoting is now available for &(lsearch)&.
them are expanded every time they are used; others are expanded only once.
When a string is being expanded it is copied verbatim from left to right except
+.cindex expansion "string concatenation"
when a dollar or backslash character is encountered. A dollar specifies the
start of a portion of the string that is interpreted and replaced as described
below in section &<<SECTexpansionitems>>& onwards. Backslash is used as an
returns the SHA-1 hash fingerprint of the certificate.
-.vitem &*${sha256:*&<&'string'&>&*}*&
+.vitem &*${sha256:*&<&'string'&>&*}*& &&&
+ &*${sha2:*&<&'string'&>&*}*& &&&
+ &*${sha2_<n>:*&<&'string'&>&*}*&
.cindex "SHA-256 hash"
+.cindex "SHA-2 hash"
.cindex certificate fingerprint
.cindex "expansion" "SHA-256 hashing"
.cindex "&%sha256%& expansion item"
+.cindex "&%sha2%& expansion item"
The &%sha256%& operator computes the SHA-256 hash value of the string
and returns
it as a 64-digit hexadecimal number, in which any letters are in upper case.
If the string is a single variable of type certificate,
returns the SHA-256 hash fingerprint of the certificate.
+.new
+The operator can also be spelled &%sha2%& and does the same as &%sha256%&
+(except for certificates, which are not supported).
+Finally, if an underbar
+and a number is appended it specifies the output length, selecting a
+member of the SHA-2 family of hash functions.
+Values of 256, 384 and 512 are accepted, with 256 being the default.
+.wen
+
.vitem &*${sha3:*&<&'string'&>&*}*& &&&
&*${sha3_<n>:*&<&'string'&>&*}*&
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.
+This value may be overridden by the &%exim_version%& main config option.
.vitem &$header_$&<&'name'&>
This is not strictly an expansion variable. It is expansion syntax for
.vitem &$version_number$&
.vindex "&$version_number$&"
-The version number of Exim.
+The version number of Exim. Same as &$exim_version$&, may be overridden
+by the &%exim_version%& main config option.
.vitem &$warn_message_delay$&
.vindex "&$warn_message_delay$&"
used. See chapter &<<CHAPsecurity>>& for a discussion of security issues.
+.option exim_version main string "current version"
+.cindex "Exim version"
+.cindex customizing "version number"
+.cindex "version number of Exim" override
+This option allows to override the &$version_number$&/&$exim_version$& Exim reports in
+various places. Use with care, this may fool stupid security scanners.
+
+
.option extra_local_interfaces main "string list" unset
This option defines network interfaces that are to be considered local when
routing, but which are not used for listening by the daemon. See section
transport driver.
-.option openssl_options main "string list" "+no_sslv2 +single_dh_use +no_ticket"
+.option openssl_options main "string list" "+no_sslv2 +no_sslv3 +single_dh_use +no_ticket"
.cindex "OpenSSL "compatibility options"
This option allows an administrator to adjust the SSL options applied
by OpenSSL to connections. It is given as a space-separated list of items,
option in the relevant &(smtp)& transport.
&*Note*&: If you use filenames based on IP addresses, change the list
-separator in the usual way (&<<SECTlistsepchange>>&) >to avoid confusion under IPv6.
+separator in the usual way (&<<SECTlistsepchange>>&) to avoid confusion under IPv6.
&*Note*&: Under versions of OpenSSL preceding 1.1.1,
when a list of more than one
message on the same connection. See section &<<SECTmulmessam>>& for an
explanation of when this might be needed.
-.option hosts_noproxy_tls smtp "host list&!!" *
+.new
+.option hosts_noproxy_tls smtp "host list&!!" unset
.cindex "TLS" "passing connection"
.cindex "multiple SMTP deliveries"
.cindex "TLS" "multiple message deliveries"
For any host that matches this list, a TLS session which has
been started will not be passed to a new delivery process for sending another
message on the same session.
+.wen
The traditional implementation closes down TLS and re-starts it in the new
process, on the same open TCP connection, for each successive message
CHUNKING support, Exim will attempt to use BDAT commands rather than DATA.
BDAT will not be used in conjunction with a transport filter.
-.option hosts_try_dane smtp "host list&!!" unset
+.option hosts_try_dane smtp "host list&!!" *
.cindex DANE "transport options"
.cindex DANE "attempting for certain servers"
If built with DANE support, Exim will lookup a
-.section "Configuring an Exim client to use TLS" "SECID185"
+.section "Configuring an Exim client to use TLS" "SECTclientTLS"
.cindex "cipher" "logging"
.cindex "log" "TLS cipher"
.cindex "log" "distinguished name"
option), this condition is always true.
-.vitem &*verify&~=&~not_blind*&
+.vitem &*verify&~=&~not_blind/*&<&'options'&>
.cindex "verifying" "not blind"
.cindex "bcc recipients, verifying none"
This condition checks that there are no blind (bcc) recipients in the message.
&'Resent-Cc:'& header lines exist, they are also checked. This condition can be
used only in a DATA or non-SMTP ACL.
+.new
+There is one possible option, &`case_insensitive`&. If this is present then
+local parts are checked case-insensitively.
+.wen
+
There are, of course, many legitimate messages that make use of blind (bcc)
recipients. This check should not be used on its own for blocking messages.
&`F `& sender address (on delivery lines)
&`H `& host name and IP address
&`I `& local interface used
-&`id `& message id for incoming message
+&`id `& message id (from header) for incoming message
&`K `& CHUNKING extension used
&`L `& on &`<=`& and &`=>`& lines: PIPELINING extension used
&`M8S `& 8BITMIME status for incoming message
&` incoming_port `& remote port on <= lines
&`*lost_incoming_connection `& as it says (includes timeouts)
&` millisec `& millisecond timestamps and RT,QT,DT,D times
+&`*msg_id `& on <= lines, Message-ID: header value
+&` msg_id_created `& on <= lines, Message-ID: header value when one had to be added
&` outgoing_interface `& local interface on => lines
&` outgoing_port `& add remote port to => lines
&`*queue_run `& start and end queue runs
&%millisec%&: Timestamps have a period and three decimal places of finer granularity
appended to the seconds value.
.next
+.new
+.cindex "log" "message id"
+&%msg_id%&: The value of the Message-ID: header.
+.next
+&%msg_id_created%&: The value of the Message-ID: header, when one had to be created.
+This will be either because the message is a bounce, or was submitted locally
+(submission mode) without one.
+The field identifier will have an asterix appended: &"id*="&.
+.wen
+.next
.cindex "log" "outgoing interface"
.cindex "log" "local interface"
.cindex "log" "local address and port"
.vitem &*-x*&
Match only non-frozen messages.
+
+.new
+.vitem &*-G*&&~<&'queuename'&>
+Match only messages in the given queue. Without this, the default queue is searched.
+.wen
.endlist
The following options control the format of the output:
.cindex "DKIM" "signing"
For signing to be usable you must have published a DKIM record in DNS.
-Note that RFC 8301 says:
+Note that RFC 8301 (which does not cover EC keys) says:
.code
rsa-sha1 MUST NOT be used for signing or verifying.
.option dkim_domain smtp string list&!! unset
The domain(s) you want to sign with.
After expansion, this can be a list.
-Each element in turn is put into the &%$dkim_domain%& expansion variable
+Each element in turn,
+.new
+lowercased,
+.wen
+is put into the &%$dkim_domain%& expansion variable
while expanding the remaining signing options.
If it is empty after expansion, DKIM signing is not done,
and no error will result even if &%dkim_strict%& is set.
Signers SHOULD use RSA keys of at least 2048 bits.
.endd
-Support for EC keys is being developed under
-&url(https://datatracker.ietf.org/doc/draft-ietf-dcrup-dkim-crypto/).
+.new
+EC keys for DKIM are defined by RFC 8463.
+.wen
They are considerably smaller than RSA keys for equivalent protection.
As they are a recent development, users should consider dual-signing
(by setting a list of selectors, and an expansion for this option)
certtool --load_privkey=dkim_ed25519.private --pubkey_info --outder | tail -c +13 | base64
.endd
-Note that the format
-of Ed25519 keys in DNS has not yet been decided; this release supports
-both of the leading candidates at this time, a future release will
-probably drop support for whichever proposal loses.
+.new
+Exim also supports an alternate format
+of Ed25519 keys in DNS which was a candidate during development
+of the standard, but not adopted.
+A future release will probably drop that support.
+.wen
.option dkim_hash smtp string&!! sha256
Can be set to any one of the supported hash methods, which are:
If a domain or identity is listed several times in the (expanded) value of
&%dkim_verify_signers%&, the ACL is only called once for that domain or identity.
+.new
+Note that if the option is set using untrustworthy data
+(such as the From: header)
+care should be taken to force lowercase for domains
+and for the domain part if identities.
+The default setting can be regarded as trustworthy in this respect.
+.wen
+
If multiple signatures match a domain (or identity), the ACL is called once
for each matching signature.
git://git.exim.org / exim.git / blobdiff