remote_smtp:
driver = smtp
message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
-.ifdef _HAVE_DANE
- hosts_try_dane = *
-.endif
.ifdef _HAVE_PRDR
hosts_try_prdr = *
.endif
With &"strict"& a response from the DNS resolver that
is not labelled as authenticated data
is treated as equivalent to a temporary DNS error.
-The default is &"never"&.
+The default is &"lax"&.
See also the &$lookup_dnssec_authenticated$& variable.
commands are acceptable.
When used, the pipelining saves on roundtrip times.
+See also the &%hosts_pipe_connect%& smtp transport option.
+
Currently the option name &"X_PIPE_CONNECT"& is used.
.wen
The value of this option is expanded and indicates the source of DH parameters
to be used by Exim.
-&*Note: The Exim Maintainers strongly recommend using a filename with site-generated
+.new
+This option is ignored for GnuTLS version 3.6.0 and later.
+The library manages parameter negotiation internally.
+.wen
+
+&*Note: The Exim Maintainers strongly recommend,
+for other TLS library versions,
+using a filename with site-generated
local DH parameters*&, which has been supported across all versions of Exim. The
other specific constants available are a fallback so that even when
"unconfigured", Exim can offer Perfect Forward Secrecy in older ciphersuites in TLS.
Usable for GnuTLS 3.4.4 or 3.3.17 or OpenSSL 1.1.0 (or later).
-For GnuTLS 3.5.6 or later the expanded value of this option can be a list
+.new
+For OpenSSL 1.1.0 or later, and
+.wen
+for GnuTLS 3.5.6 or later the expanded value of this option can be a list
of files, to match a list given for the &%tls_certificate%& option.
The ordering of the two lists must match.
.new
The file(s) should be in DER format,
-except for GnuTLS 3.6.3 or later when an optional filetype prefix
-can be used. The prefix must be one of "DER" or "PEM", followed by
+except for GnuTLS 3.6.3 or later
+or for OpenSSL,
+when an optional filetype prefix can be used.
+The prefix must be one of "DER" or "PEM", followed by
a single space. If one is used it sets the format for subsequent
files in the list; the initial format is DER.
-When a PEM format file is used it may contain multiple proofs,
-for multiple certificate chain element proofs under TLS1.3.
+If multiple proofs are wanted, for multiple chain elements
+(this only works under TLS1.3)
+they must be coded as a combined OCSP response.
+
+Although GnuTLS will accept PEM files with multiple separate
+PEM blobs (ie. separate OCSP responses), it sends them in the
+TLS Certificate record interleaved with the certificates of the chain;
+although a GnuTLS client is happy with that, an OpenSSL client is not.
.wen
.option tls_on_connect_ports main "string list" unset
unless you really, really know what you are doing. See also the generic
transport option of the same name.
-.option dnssec_request_domains routers "domain list&!!" unset
+.option dnssec_request_domains routers "domain list&!!" *
.cindex "MX record" "security"
.cindex "DNSSEC" "MX lookup"
.cindex "security" "MX lookup"
details.
-.option dnssec_request_domains smtp "domain list&!!" unset
+.option dnssec_request_domains smtp "domain list&!!" *
.cindex "MX record" "security"
.cindex "DNSSEC" "MX lookup"
.cindex "security" "MX lookup"
It also turns SMTP into a client-first protocol
so combines well with TCP Fast Open.
+See also the &%pipelining_connect_advertise_hosts%& main option.
+
Note:
When the facility is used, the transport &%helo_data%& option
will be expanded before the &$sending_ip_address$& variable
If DANE is not usable, whether requested or not, and CA-anchored
verification evaluation is wanted, the above variables should be set appropriately.
-Currently the (router or transport options) &%dnssec_request_domains%& must be active and &%dnssec_require_domains%& is ignored.
+The router and transport option &%dnssec_request_domains%& must not be
+set to "never" and &%dnssec_require_domains%& is ignored.
If verification was successful using DANE then the "CV" item in the delivery log line will show as "CV=dane".
The name is placed in the variable &$event_name$& and the event action
expansion must check this, as it will be called for every possible event type.
+.new
The current list of events is:
+.wen
.display
&`dane:fail after transport `& per connection
&`msg:complete after main `& per message
&`tcp:close after transport `& per connection
&`tls:cert before both `& per certificate in verification chain
&`smtp:connect after transport `& per connection
+&`smtp:ehlo after transport `& per connection
.endd
New event types may be added in future.
&`msg:host:defer `& error string
&`tls:cert `& verification chain depth
&`smtp:connect `& smtp banner
+&`smtp:ehlo `& smtp ehlo response
.endd
The :defer events populate one extra variable: &$event_defer_errno$&.