diff --git a/bin/tests/system/legacy/tests.sh b/bin/tests/system/legacy/tests.sh
index 5a7da20963..8a286cc4f4 100755
--- a/bin/tests/system/legacy/tests.sh
+++ b/bin/tests/system/legacy/tests.sh
@@ -14,6 +14,33 @@ SYSTEMTESTTOP=..
 
 DIGOPTS="-p ${PORT} +tries=3 +time=5"
 
+# Check whether the SOA record for the name provided in $1 can be resolved by
+# ns1.  Return 0 if resolution succeeds as expected; return 1 otherwise.
+resolution_succeeds() {
+	_ret=0
+	$DIG $DIGOPTS +tcp @10.53.0.1 ${1} SOA > dig.out.test$n || _ret=1
+	grep "status: NOERROR" dig.out.test$n > /dev/null || _ret=1
+	return $_ret
+}
+
+# Check whether the SOA record for the name provided in $1 can be resolved by
+# ns1.  Return 0 if resolution fails as expected; return 1 otherwise.  Note that
+# both a SERVFAIL response and timing out mean resolution failed, so the exit
+# code of dig does not influence the result (the exit code for a SERVFAIL
+# response is 0 while the exit code for not getting a response at all is not 0).
+resolution_fails() {
+	_servfail=0
+	_timeout=0
+	$DIG $DIGOPTS +tcp @10.53.0.1 ${1} SOA > dig.out.test$n
+	grep "status: SERVFAIL" dig.out.test$n > /dev/null && _servfail=1
+	grep "connection timed out" dig.out.test$n > /dev/null && _timeout=1
+	if [ $_servfail -eq 1 ] || [ $_timeout -eq 1 ]; then
+		return 0
+	else
+		return 1
+	fi
+}
+
 status=0
 n=0
 
@@ -30,8 +57,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to formerr edns server succeeds ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 ednsformerr soa > dig.out.test$n || ret=1
-grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
+resolution_succeeds ednsformerr. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -48,8 +74,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to notimp edns server fails ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 ednsnotimp soa > dig.out.test$n
-grep "status: NOERROR" dig.out.test$n > /dev/null && ret=1
+resolution_fails ednsnotimp. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -66,8 +91,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to refused edns server fails ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 ednsrefused soa > dig.out.test$n
-grep "status: NOERROR" dig.out.test$n > /dev/null && ret=1
+resolution_fails ednsrefused. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -90,8 +114,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to drop edns server fails ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 dropedns soa > dig.out.test$n
-grep "status: NOERROR" dig.out.test$n > /dev/null && ret=1
+resolution_fails dropedns. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -111,8 +134,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to drop edns + no tcp server fails ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 dropedns-notcp soa > dig.out.test$n
-grep "status: NOERROR" dig.out.test$n > /dev/null && ret=1
+resolution_fails dropedns-notcp. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -128,8 +150,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to plain dns server succeeds ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 plain soa > dig.out.test$n || ret=1
-grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
+resolution_succeeds plain. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -147,8 +168,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to plain dns + no tcp server succeeds ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 plain-notcp soa > dig.out.test$n || ret=1
-grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
+resolution_succeeds plain-notcp. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 n=`expr $n + 1`
@@ -170,8 +190,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to edns 512 server succeeds ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 edns512 soa > dig.out.test$n || ret=1
-grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
+resolution_succeeds edns512. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -193,8 +212,7 @@ status=`expr $status + $ret`
 n=`expr $n + 1`
 echo_i "checking recursive lookup to edns 512 + no tcp server fails ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 edns512-notcp soa > dig.out.test$n || ret=1
-grep "status: NOERROR" dig.out.test$n > /dev/null && ret=1
+resolution_fails edns512-notcp. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
@@ -205,9 +223,7 @@ $PERL $SYSTEMTESTTOP/start.pl --noclean --restart --port ${PORT} legacy ns1
 n=`expr $n + 1`
 echo_i "checking recursive lookup to edns 512 + no tcp + trust anchor fails ($n)"
 ret=0
-$DIG $DIGOPTS +tcp @10.53.0.1 edns512-notcp soa > dig.out.test$n
-grep "status: SERVFAIL" dig.out.test$n > /dev/null ||
-    grep "connection timed out;" dig.out.test$n > /dev/null || ret=1
+resolution_fails edns512-notcp. || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`