Support transport-added headers under cutthrough delivery. Bug 1431

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

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index ae4d75ecb924398e4fe613df4f602af918fe83d7..2b055c3e9978603326c1dcce571bea511d3eab63 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -27330,8 +27330,12 @@ from one SMTP connection to another.  If a recipient-verify callout connection i
 requested in the same ACL it is held open and used for the data, otherwise one is made
 after the ACL completes.
 
 requested in the same ACL it is held open and used for the data, otherwise one is made
 after the ACL completes.
 

-Note that routers are used in verify mode.  Note also that headers cannot be
+Note that routers are used in verify mode,
+and cannot depend on content of received headers.
+Note also that headers cannot be

 modified by any of the post-data ACLs (DATA, MIME and DKIM).
 modified by any of the post-data ACLs (DATA, MIME and DKIM).

+Headers may be modified by routers (subject to the above) and transports.
+

 Cutthrough delivery is not supported via transport-filters or when DKIM signing
 of outgoing messages is done, because it sends data to the ultimate destination
 before the entire message has been received from the source.
 Cutthrough delivery is not supported via transport-filters or when DKIM signing
 of outgoing messages is done, because it sends data to the ultimate destination
 before the entire message has been received from the source.