Docs: add note on DKIM vs. tpt modifying headers

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 902f8e72f2e7f9748fae66977bbbec8e84f91d56..d030a8411105d09657b1964b00c3fa5a0045d72e 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -17472,16 +17472,26 @@ or if the message was submitted locally (not using TCP/IP), and the &%-bnq%&
 option was not set.
 
 
-.option recipients_max main integer 50000
+.option recipients_max main integer&!! 50000
 .cindex "limit" "number of recipients"
 .cindex "recipient" "maximum number"
-If this option is set greater than zero, it specifies the maximum number of
+If the value resulting from expanding this option
+is set greater than zero, it specifies the maximum number of
 original recipients for any message. Additional recipients that are generated
 by aliasing or forwarding do not count. SMTP messages get a 452 response for
 all recipients over the limit; earlier recipients are delivered as normal.
 Non-SMTP messages with too many recipients are failed, and no deliveries are
 done.
 
+.new
+For SMTP message the expansion is done after the connection is
+accepted (but before any SMTP conversation) and may depend on
+the IP addresses and port numbers of the connection.
+&*Note*&: If an expansion is used for the option,
+care should be taken that a resonable value results for
+non-SMTP messages.
+.wen
+
 .cindex "RCPT" "maximum number of incoming"
 &*Note*&: The RFCs specify that an SMTP server should accept at least 100
 RCPT commands in a single message.
@@ -30755,6 +30765,10 @@ and the &%acl_smtp_mime%& ACLs.
 The &%acl_smtp_dkim%& ACL is available only when Exim is compiled with DKIM support
 enabled (which is the default).
 
+If, for a specific message, an ACL control
+&*dkim_disable_verify*&
+has been set, this &%acl_smtp_dkim%& ACL is not called.
+
 The ACL test specified by &%acl_smtp_dkim%& happens after a message has been
 received, and is executed for each DKIM signature found in a message.  If not
 otherwise specified, the default action is to accept.
@@ -41586,8 +41600,11 @@ Exim's DKIM implementation allows for
 .olist
 Signing outgoing messages: This function is implemented in the SMTP transport.
 It can co-exist with all other Exim features
-(including transport filters)
-except cutthrough delivery.
+(including transport filters) except cutthrough delivery.
+.new
+However, signing options may not depend on headers modified by
+routers, the transport or a transport filter.
+.wen
 .next
 Verifying signatures in incoming messages: This is implemented by an additional
 ACL (acl_smtp_dkim), which can be called several times per message, with