Recognised RDN type labels include "CN", "O", "OU" and "DC".
The field selectors marked as "time" above
-may output a number of seconds since epoch
-if the modifier "int" is used.
+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,
values of &$received_ip_address$& and &$received_port$& are saved with any
messages that are received, thus making these variables available at delivery
time.
-
-&*Note:*& There are no equivalent variables for outgoing connections, because
-the values are unknown (unless they are explicitly set by options of the
-&(smtp)& transport).
+For outbound connections see &$sending_ip_address$&.
.vitem &$received_port$&
.vindex "&$received_port$&"
.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 "&$sender_host_authenticated$&"
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.
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:
For earlier versions of GnuTLS
the option must be set to the name of a single file.
+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.
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
in clear.
-.option tls_try_verify_hosts smtp "host list&!! unset
+.option tls_try_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,
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 set.
+when &%tls_verify_certificates%& is matched.
The &$tls_out_certificate_verified$& variable is set when
certificate verification succeeds.
files.
For earlier versions of GnuTLS the option must be set to the name of a
single file.
+
+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.
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,
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
&%tls_verify_certificates%&
.next
.vindex "&%tls_ocsp_file%&"
-&%tls_verify_certificates%&
+&%tls_ocsp_file%&
.endlist
Great care should be taken to deal with matters of case, various injection
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