diff --git a/bin/dig/dig.docbook b/bin/dig/dig.docbook
index 22ba7f2ed1..f177ca713e 100644
--- a/bin/dig/dig.docbook
+++ b/bin/dig/dig.docbook
@@ -1330,7 +1330,9 @@ dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr
       reply from the server.
       If you'd like to turn off the IDN support for some reason, use
       parameters <parameter>+noidnin</parameter> and
-      <parameter>+noidnout</parameter>.
+      <parameter>+noidnout</parameter> or define
+      the <envar>IDN_DISABLE</envar> environment variable.
+
     </para>
   </refsection>
 
diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index 2903bb020c..522c5761f4 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -628,8 +628,8 @@ make_empty_lookup(void) {
 	looknew->ttlunits = false;
 	looknew->qr = false;
 #ifdef HAVE_LIBIDN2
-	looknew->idnin = true;
-	looknew->idnout = true;
+	looknew->idnin = (getenv("IDN_DISABLE") == NULL);
+	looknew->idnout = looknew->idnin;
 #else
 	looknew->idnin = false;
 	looknew->idnout = false;
diff --git a/bin/dig/host.docbook b/bin/dig/host.docbook
index 36fcf51de4..1db8798d30 100644
--- a/bin/dig/host.docbook
+++ b/bin/dig/host.docbook
@@ -389,7 +389,7 @@
       <command>host</command> appropriately converts character encoding of
       domain name before sending a request to DNS server or displaying a
       reply from the server.
-      If you'd like to turn off the IDN support for some reason, defines
+      If you'd like to turn off the IDN support for some reason, define
       the <envar>IDN_DISABLE</envar> environment variable.
       The IDN support is disabled if the variable is set when
       <command>host</command> runs.
diff --git a/bin/dig/nslookup.docbook b/bin/dig/nslookup.docbook
index 3aff4e984d..86a09c658e 100644
--- a/bin/dig/nslookup.docbook
+++ b/bin/dig/nslookup.docbook
@@ -478,6 +478,21 @@ nslookup -query=hinfo  -timeout=10
     </para>
   </refsection>
 
+  <refsection><info><title>IDN SUPPORT</title></info>
+
+    <para>
+      If <command>nslookup</command> has been built with IDN (internationalized
+      domain name) support, it can accept and display non-ASCII domain names.
+      <command>nslookup</command> appropriately converts character encoding of
+      domain name before sending a request to DNS server or displaying a
+      reply from the server.
+      If you'd like to turn off the IDN support for some reason, define
+      the <envar>IDN_DISABLE</envar> environment variable.
+      The IDN support is disabled if the variable is set when
+      <command>nslookup</command> runs.
+    </para>
+  </refsection>
+
   <refsection><info><title>FILES</title></info>
 
     <para><filename>/etc/resolv.conf</filename>