diff --git a/CHANGES b/CHANGES
index 51800751f0..48c83f0392 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,8 @@
+4236.	[func]		On machines with 4 or more processors (CPU), the
+			default value for the number of UDP listeners
+			has been changed to the number of detected
+			processors minus one. [RT #40761]
+
 4233.	[test]		Add tests for CDS and CDNSKEY with delegation-only.
 			[RT #40597]
 
diff --git a/bin/named/main.c b/bin/named/main.c
index d951ef5021..408a5ca14d 100644
--- a/bin/named/main.c
+++ b/bin/named/main.c
@@ -705,6 +705,8 @@ create_managers(void) {
 	isc_result_t result;
 	unsigned int socks;
 
+	INSIST(ns_g_cpus_detected > 0);
+
 #ifdef ISC_PLATFORM_USETHREADS
 	if (ns_g_cpus == 0)
 		ns_g_cpus = ns_g_cpus_detected;
@@ -721,10 +723,8 @@ create_managers(void) {
 	if (ns_g_udpdisp == 0) {
 		if (ns_g_cpus_detected == 1)
 			ns_g_udpdisp = 1;
-		else if (ns_g_cpus_detected < 4)
-			ns_g_udpdisp = 2;
 		else
-			ns_g_udpdisp = ns_g_cpus_detected / 2;
+			ns_g_udpdisp = ns_g_cpus_detected - 1;
 	}
 	if (ns_g_udpdisp > ns_g_cpus)
 		ns_g_udpdisp = ns_g_cpus;
diff --git a/doc/arm/notes.xml b/doc/arm/notes.xml
index d7eedea74a..23b9a92fc7 100644
--- a/doc/arm/notes.xml
+++ b/doc/arm/notes.xml
@@ -210,6 +210,13 @@
 	   transport the query was received over.
 	</para>
       </listitem>
+      <listitem>
+	<para>
+	  On machines with 4 or more processors (CPU), the default value
+	  for the number of UDP listeners has been changed to the number
+	  of detected processors minus one.
+	</para>
+      </listitem>
     </itemizedlist>
   </sect2>
   <sect2 id="relnotes_port">