Docs: clarify DKIM default signing. Bug 2179

[user/henk/code/exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 29d0d900edcdf99fde6126e7e7fb64018da0c8c0..a9a048ecb3640fa30028675eece740f19011cebe 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -23806,7 +23806,7 @@ of the message. Its value must not be zero. See also &%final_timeout%&.
 .option dkim_private_key smtp string&!! unset
 .option dkim_canon smtp string&!! unset
 .option dkim_strict smtp string&!! unset
-.option dkim_sign_headers smtp string&!! unset
+.option dkim_sign_headers smtp string&!! "per RFC"
 .option dkim_hash smtp string&!! sha256
 .option dkim_identity smtp string&!! unset
 DKIM signing options.  For details see section &<<SECDKIMSIGN>>&.
@@ -24147,7 +24147,7 @@ This option provides a list of servers to which, provided they announce
 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_fastopen smtp "host list!!" unset
+.option hosts_try_fastopen smtp "host list&!!" unset
 .cindex "fast open, TCP" "enabling, in client"
 .cindex "TCP Fast Open" "enabling, in client"
 .cindex "RFC 7413" "TCP Fast Open"
@@ -24163,6 +24163,9 @@ as the initiator must present a cookie in the SYN segment.
 
 On (at least some) current Linux distributions the facility must be enabled
 in the kernel by the sysadmin before the support is usable.
+There is no option for control of the server side; if the system supports
+it it is always enebled.  Note that legthy operations in the connect ACL,
+such as DNSBL lookups, will still delay the emission of the SMTP banner.
 
 .option hosts_try_prdr smtp "host list&!!" *
 .cindex "PRDR" "enabling, optional in client"
@@ -38588,11 +38591,17 @@ either "1" or "true", Exim will defer. Otherwise Exim will send the message
 unsigned. You can use the &%$dkim_domain%& and &%$dkim_selector%& expansion
 variables here.
 
-.option dkim_sign_headers smtp string&!! unset
-If set, this option must expand to (or be specified as) a colon-separated
-list of header names. Headers with these names will be included in the message
-signature.
-When unspecified, the header names recommended in RFC4871 will be used.
+.option dkim_sign_headers smtp string&!! "see below"
+If set, this option must expand to a colon-separated
+list of header names.
+.new
+Headers with these names, or the absence or such a header, will be included
+in the message signature.
+When unspecified, the header names listed in RFC4871 will be used,
+whether or not each header is present in the message.
+The default list is available for the expansion in the macro
+"_DKIM_SIGN_HEADERS".
+.wen
 
 
 .section "Verifying DKIM signatures in incoming mail" "SECID514"