tls_dh_min_bits smtp transport option

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

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 9637b5194188538ae1397cb9746947db5eac3f96..78d5b0b183041375c924889e53989a2097e632cf 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -2937,6 +2937,7 @@ use the &'exim_dbmbuild'& utility, or some other means, to rebuild alias files
 if this is required. If the &%bi_command%& option is not set, calling Exim with
 &%-bi%& is a no-op.
 
+.new
 .vitem &%-bI:help%&
 .oindex "&%-bI:help%&"
 .cindex "querying exim information"
@@ -2955,6 +2956,7 @@ useful for ManageSieve (RFC 5804) implementations, in providing that protocol's
 &`SIEVE`& capability response line.  As the precise list may depend upon
 compile-time build options, which this option will adapt to, this is the only
 way to guarantee a correct response.
+.wen
 
 .vitem &%-bm%&
 .oindex "&%-bm%&"
@@ -3069,6 +3071,12 @@ configuration file is output.
 If a list of configuration files was supplied, the value that is output here
 is the name of the file that was actually used.
 
+.new
+.cindex "options" "hiding name of"
+If the &%-n%& flag is given, then for most modes of &%-bP%& operation the
+name will not be output.
+.wen
+
 .cindex "daemon" "process id (pid)"
 .cindex "pid (process id)" "of daemon"
 If &%log_file_path%& or &%pid_file_path%& are given, the names of the
@@ -3930,9 +3938,9 @@ for that message.
 
 .vitem &%-n%&
 .oindex "&%-n%&"
-.cindex "Sendmail compatibility" "&%-n%& option ignored"
-This option is interpreted by Sendmail to mean &"no aliasing"&. It is ignored
-by Exim.
+This option is interpreted by Sendmail to mean &"no aliasing"&.
+For normal modes of operation, it is ignored by Exim.
+When combined with &%-bP%& it suppresses the name of an option from being output.
 
 .vitem &%-O%&&~<&'data'&>
 .oindex "&%-O%&"
@@ -22443,6 +22451,19 @@ This option specifies a certificate revocation list. The expanded value must
 be the name of a file that contains a CRL in PEM format.
 
 
+.new
+.option tls_dh_min_bits smtp integer 1024
+.cindex "TLS" "Diffie-Hellman minimum acceptable size"
+When establishing a TLS session, if a ciphersuite which uses Diffie-Hellman
+key agreement is negotiated, the server will provide a large prime number
+for use.  This option establishes the minimum acceptable size of that number.
+If the parameter offered by the server is too small, then the TLS handshake
+will fail.
+
+Only supported when using GnuTLS.
+.wen
+
+
 .option tls_privatekey smtp string&!! unset
 .cindex "TLS" "client private key, location of"
 .vindex "&$host$&"
@@ -24996,6 +25017,13 @@ option).
 The &%tls_require_ciphers%& options operate differently, as described in the
 sections &<<SECTreqciphssl>>& and &<<SECTreqciphgnu>>&.
 .next
+.new
+The &%tls_dh_min_bits%& SMTP transport option is only honoured by GnuTLS.
+When using OpenSSL, this option is ignored.
+(If an API is found to let OpenSSL be configured in this way,
+let the Exim Maintainers know and we'll likely use it).
+.wen
+.next
 Some other recently added features may only be available in one or the other.
 This should be documented with the feature.  If the documentation does not
 explicitly state that the feature is infeasible in the other TLS