diff --git a/bin/tests/system/digdelv/prereq.sh b/bin/tests/system/digdelv/prereq.sh
new file mode 100644
index 0000000000..de147a4c2a
--- /dev/null
+++ b/bin/tests/system/digdelv/prereq.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi
diff --git a/bin/tests/system/fetchlimit/prereq.sh b/bin/tests/system/fetchlimit/prereq.sh
new file mode 100644
index 0000000000..de147a4c2a
--- /dev/null
+++ b/bin/tests/system/fetchlimit/prereq.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi
diff --git a/bin/tests/system/rpzrecurse/prereq.sh b/bin/tests/system/rpzrecurse/prereq.sh
index c8fe3b885c..6f0487eae8 100644
--- a/bin/tests/system/rpzrecurse/prereq.sh
+++ b/bin/tests/system/rpzrecurse/prereq.sh
@@ -21,4 +21,12 @@ if [ $ret != 0 ]; then
     exit 1
 fi
 
-exec $SHELL ../testcrypto.sh
+$SHELL ../testcrypto.sh || exit 255
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi
diff --git a/bin/tests/system/zero/prereq.sh b/bin/tests/system/zero/prereq.sh
new file mode 100644
index 0000000000..de147a4c2a
--- /dev/null
+++ b/bin/tests/system/zero/prereq.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi
diff --git a/util/copyrights b/util/copyrights
index 33d7d0649d..8f78536c2a 100644
--- a/util/copyrights
+++ b/util/copyrights
@@ -983,6 +983,7 @@
 ./bin/tests/system/digdelv/ns2/example.db	ZONE	2015,2016,2018
 ./bin/tests/system/digdelv/ns2/named.conf.in	CONF-C	2018
 ./bin/tests/system/digdelv/ns3/named.conf.in	CONF-C	2018
+./bin/tests/system/digdelv/prereq.sh		SH	2018
 ./bin/tests/system/digdelv/setup.sh		SH	2018
 ./bin/tests/system/digdelv/tests.sh		SH	2015,2016,2017,2018
 ./bin/tests/system/ditch.pl			PERL	2015,2016,2018
@@ -1309,6 +1310,7 @@
 ./bin/tests/system/fetchlimit/ns3/named2.conf.in	CONF-C	2018
 ./bin/tests/system/fetchlimit/ns3/named3.conf.in	CONF-C	2018
 ./bin/tests/system/fetchlimit/ns3/root.hint	ZONE	2015,2016,2018
+./bin/tests/system/fetchlimit/prereq.sh		SH	2018
 ./bin/tests/system/fetchlimit/setup.sh		SH	2015,2016,2018
 ./bin/tests/system/fetchlimit/tests.sh		SH	2015,2016,2018
 ./bin/tests/system/filter-aaaa/.gitignore	X	2012,2014,2016,2018
@@ -2377,6 +2379,7 @@
 ./bin/tests/system/zero/ns3/root.hint		ZONE	2013,2016,2018
 ./bin/tests/system/zero/ns4/named.conf.in	CONF-C	2018
 ./bin/tests/system/zero/ns4/one.tld.db		ZONE	2016,2018
+./bin/tests/system/zero/prereq.sh		SH	2018
 ./bin/tests/system/zero/setup.sh		SH	2013,2014,2016,2018
 ./bin/tests/system/zero/tests.sh		SH	2013,2016,2017,2018
 ./bin/tests/system/zonechecks/a.db		ZONE	2004,2007,2016,2018