diff --git a/CHANGES b/CHANGES
index b35f597d3c..73e03ec7d3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+4201.	[func]		The default preferred-glue is now the address record
+			type of the transport the query was received
+			over.  [RT #40468]
+
 4200.	[cleanup]	win32: update BINDinstall to be BIND release
 			independent. [RT #38915]
 
diff --git a/bin/named/client.c b/bin/named/client.c
index 683305c151..5407e296b9 100644
--- a/bin/named/client.c
+++ b/bin/named/client.c
@@ -1000,6 +1000,12 @@ client_send(ns_client_t *client) {
 		else if (client->view->preferred_glue == dns_rdatatype_aaaa)
 			preferred_glue = DNS_MESSAGERENDER_PREFER_AAAA;
 	}
+	if (preferred_glue == 0) {
+		if (isc_sockaddr_pf(&client->peeraddr) == AF_INET)
+			preferred_glue = DNS_MESSAGERENDER_PREFER_A;
+		else
+			preferred_glue = DNS_MESSAGERENDER_PREFER_AAAA;
+	}
 
 #ifdef ALLOW_FILTER_AAAA
 	/*
diff --git a/doc/arm/Bv9ARM-book.xml b/doc/arm/Bv9ARM-book.xml
index 119d5dd5d0..a82522fb86 100644
--- a/doc/arm/Bv9ARM-book.xml
+++ b/doc/arm/Bv9ARM-book.xml
@@ -5471,7 +5471,9 @@ badresp:1,adberr:0,findfail:0,valfail:0]
 		If specified, the listed type (A or AAAA) will be emitted
 		before other glue
 		in the additional section of a query response.
-		The default is not to prefer any type (NONE).
+		The default is to prefer A records when responding
+		to queries that arrived via IPv4 and AAAA when
+		responding to queries that arrived via IPv6.
 	      </para>
 	    </listitem>
 	  </varlistentry>
diff --git a/doc/arm/notes.xml b/doc/arm/notes.xml
index accc37b8c9..cf25f71166 100644
--- a/doc/arm/notes.xml
+++ b/doc/arm/notes.xml
@@ -203,6 +203,12 @@
 	  as specified in RFC 6763. [RT #37889]
 	</para>
       </listitem>
+      <listitem>
+	<para>
+	  The default preferred glue is now the address type of the
+	   transport the query was received over.
+	</para>
+      </listitem>
     </itemizedlist>
   </sect2>
   <sect2 id="relnotes_port">