diff --git a/doc/guide/admin/tls.sdf b/doc/guide/admin/tls.sdf
index 1e2a8bfce8f9c08aa688b552f177669ae3036448..08c653460c9e2c8f6e7751924ad6be60b096cfd1 100644
--- a/doc/guide/admin/tls.sdf
+++ b/doc/guide/admin/tls.sdf
@@ -160,12 +160,13 @@ or
 H4: TLSECName <name>
 
 This directive specifies the curve to use for Elliptic Curve
-Diffie-Hellman ephemeral key exchange.  This is required in order
+Diffie-Hellman ephemeral key exchange.  This option is only needed
 to use ECDHE-based cipher suites in OpenSSL.  The names of supported
 curves may be shown using the following command
 
 >	openssl ecparam -list_curves
 
+If it is omitted, OpenSSL will auto-negotiate the curve choice.
 This directive is not used for GnuTLS.
 For GnuTLS the curves may be specified in the ciphersuite.