diff --git a/bin/tests/system/README.md b/bin/tests/system/README.md
index 7bbf339a4f..1d4d4f7b66 100644
--- a/bin/tests/system/README.md
+++ b/bin/tests/system/README.md
@@ -325,8 +325,6 @@ By default, `named` server is started with the following options:
     -m record
                     Turns on these memory usage debugging flags.
 
-    -U 4            Uses four listeners.
-
 All output is sent to a file called `named.run` in the nameserver directory.
 
 The options used to start named can be altered. There are a couple ways of
diff --git a/bin/tests/system/dnstap/ns3/named.args b/bin/tests/system/dnstap/ns3/named.args
index d70946ad15..47b682be67 100644
--- a/bin/tests/system/dnstap/ns3/named.args
+++ b/bin/tests/system/dnstap/ns3/named.args
@@ -1,2 +1,2 @@
 # Using "-n 1" allows GL #1795 to be reliably reproduced
--D dnstap-ns3 -m record -c named.conf -d 99 -g -U 4 -n 1 -T maxcachesize=2097152
+-D dnstap-ns3 -m record -c named.conf -d 99 -g -n 1 -T maxcachesize=2097152
diff --git a/bin/tests/system/enginepkcs11/ns1/named.args.in b/bin/tests/system/enginepkcs11/ns1/named.args.in
index 26d521e56c..889992190a 100644
--- a/bin/tests/system/enginepkcs11/ns1/named.args.in
+++ b/bin/tests/system/enginepkcs11/ns1/named.args.in
@@ -1 +1 @@
-@ENGINE_ARGS@ -D enginepkcs11-ns1 -m record -c named.conf -d 99 -U 4 -T maxcachesize=2097152
+@ENGINE_ARGS@ -D enginepkcs11-ns1 -m record -c named.conf -d 99 -T maxcachesize=2097152
diff --git a/bin/tests/system/legacy/ns4/named.args b/bin/tests/system/legacy/ns4/named.args
index dcd28aab4a..03dce0fafd 100644
--- a/bin/tests/system/legacy/ns4/named.args
+++ b/bin/tests/system/legacy/ns4/named.args
@@ -1 +1 @@
--m record -c named.conf -d 99 -D legacy-ns4 -g -U 4 -T maxcachesize=2097152 -T noedns
+-m record -c named.conf -d 99 -D legacy-ns4 -g -T maxcachesize=2097152 -T noedns
diff --git a/bin/tests/system/legacy/ns5/named.args b/bin/tests/system/legacy/ns5/named.args
index 1519a18988..e1311c8de8 100644
--- a/bin/tests/system/legacy/ns5/named.args
+++ b/bin/tests/system/legacy/ns5/named.args
@@ -1 +1 @@
--m record -c named.conf -d 99 -D legacy-ns5 -g -U 4 -T maxcachesize=2097152 -T noedns
+-m record -c named.conf -d 99 -D legacy-ns5 -g -T maxcachesize=2097152 -T noedns
diff --git a/bin/tests/system/legacy/ns6/named.args b/bin/tests/system/legacy/ns6/named.args
index 0bad4d37b2..1791e8b704 100644
--- a/bin/tests/system/legacy/ns6/named.args
+++ b/bin/tests/system/legacy/ns6/named.args
@@ -1 +1 @@
--m record -c named.conf -d 99 -D legacy-ns6 -g -U 4 -T maxcachesize=2097152 -T maxudp512
+-m record -c named.conf -d 99 -D legacy-ns6 -g -T maxcachesize=2097152 -T maxudp512
diff --git a/bin/tests/system/legacy/ns7/named.args b/bin/tests/system/legacy/ns7/named.args
index 7f21439519..3c90ac1c81 100644
--- a/bin/tests/system/legacy/ns7/named.args
+++ b/bin/tests/system/legacy/ns7/named.args
@@ -1 +1 @@
--m record -c named.conf -d 99 -D legacy-ns7 -g -U 4 -T maxcachesize=2097152 -T maxudp512
+-m record -c named.conf -d 99 -D legacy-ns7 -g -T maxcachesize=2097152 -T maxudp512
diff --git a/bin/tests/system/logfileconfig/named1.args b/bin/tests/system/logfileconfig/named1.args
index a76bb73f64..37ed976379 100644
--- a/bin/tests/system/logfileconfig/named1.args
+++ b/bin/tests/system/logfileconfig/named1.args
@@ -1 +1 @@
--c named.conf -m record -T nosyslog -d 99 -D logfileconfig-ns1 -U 4
+-c named.conf -m record -T nosyslog -d 99 -D logfileconfig-ns1
diff --git a/bin/tests/system/logfileconfig/named2.args b/bin/tests/system/logfileconfig/named2.args
index 787e5c980e..45347fc1b7 100644
--- a/bin/tests/system/logfileconfig/named2.args
+++ b/bin/tests/system/logfileconfig/named2.args
@@ -1 +1 @@
--c named.conf -m record -T nosyslog -d 99 -D logfileconfig-ns1 -U 4 -L named_deflog
+-c named.conf -m record -T nosyslog -d 99 -D logfileconfig-ns1 -L named_deflog
diff --git a/bin/tests/system/mirror/ns3/named.args b/bin/tests/system/mirror/ns3/named.args
index e28cf3a076..e5ebb6cda4 100644
--- a/bin/tests/system/mirror/ns3/named.args
+++ b/bin/tests/system/mirror/ns3/named.args
@@ -1 +1 @@
--D mirror-ns3 -m record -c named.conf -d 99 -g -U 4 -T maxcachesize=2097152 -T tat=3
+-D mirror-ns3 -m record -c named.conf -d 99 -g -T maxcachesize=2097152 -T tat=3
diff --git a/bin/tests/system/nsupdate/ns5/named.args b/bin/tests/system/nsupdate/ns5/named.args
index a50eb55613..64da462fd5 100644
--- a/bin/tests/system/nsupdate/ns5/named.args
+++ b/bin/tests/system/nsupdate/ns5/named.args
@@ -1 +1 @@
--D nsupdate-ns5 -m record -c named.conf -d 99 -g -U 4 -T maxcachesize=2097152 -T fixedlocal
+-D nsupdate-ns5 -m record -c named.conf -d 99 -g -T maxcachesize=2097152 -T fixedlocal
diff --git a/bin/tests/system/nsupdate/ns6/named.args b/bin/tests/system/nsupdate/ns6/named.args
index e7d800f5ae..e0a22250dd 100644
--- a/bin/tests/system/nsupdate/ns6/named.args
+++ b/bin/tests/system/nsupdate/ns6/named.args
@@ -1 +1 @@
--D nsupdate-ns6 -m record -c named.conf -d 99 -g -U 4 -T maxcachesize=2097152 -T fixedlocal
+-D nsupdate-ns6 -m record -c named.conf -d 99 -g -T maxcachesize=2097152 -T fixedlocal
diff --git a/bin/tests/system/rndc/ns6/named.args b/bin/tests/system/rndc/ns6/named.args
index 94bde0d35c..82e87714e6 100644
--- a/bin/tests/system/rndc/ns6/named.args
+++ b/bin/tests/system/rndc/ns6/named.args
@@ -1,3 +1,3 @@
 # teardown of a huge zone with tracing enabled takes way too long
 # -m none is set so that stop.pl does not timeout
--D rndc-ns6 -m none -c named.conf -d 99 -g -U 4 -T maxcachesize=2097152
+-D rndc-ns6 -m none -c named.conf -d 99 -g -T maxcachesize=2097152
diff --git a/bin/tests/system/rpzextra/ns3/named.args b/bin/tests/system/rpzextra/ns3/named.args
index 227438d376..7b5a9edf70 100644
--- a/bin/tests/system/rpzextra/ns3/named.args
+++ b/bin/tests/system/rpzextra/ns3/named.args
@@ -1 +1 @@
- -m record -c named.conf -d 99 -D rpzextra-ns1 -U 4 -T maxcachesize=2097152
+ -m record -c named.conf -d 99 -D rpzextra-ns1 -T maxcachesize=2097152
diff --git a/bin/tests/system/runtime/tests.sh b/bin/tests/system/runtime/tests.sh
index edddc08934..0d2394683c 100644
--- a/bin/tests/system/runtime/tests.sh
+++ b/bin/tests/system/runtime/tests.sh
@@ -17,7 +17,7 @@ set -e
 . ../conf.sh
 
 RNDCCMD="$RNDC -c ../_common/rndc.conf -p ${CONTROLPORT} -s"
-NAMED_DEFAULT_ARGS="-m record -d 99 -g -U 4"
+NAMED_DEFAULT_ARGS="-m record -d 99 -g"
 
 kill_named() {
   pidfile="${1}"
diff --git a/bin/tests/system/start.pl b/bin/tests/system/start.pl
index 66bb59afda..9253831782 100755
--- a/bin/tests/system/start.pl
+++ b/bin/tests/system/start.pl
@@ -280,7 +280,7 @@ sub construct_ns_command {
 			}
 		}
 
-		$command .= "-c named.conf -d 99 -g -U 4 -T maxcachesize=2097152";
+		$command .= "-c named.conf -d 99 -g -T maxcachesize=2097152";
 	}
 
 	if (-e "$testdir/$server/named.notcp") {
diff --git a/bin/tests/system/statschannel/tests.sh b/bin/tests/system/statschannel/tests.sh
index fd0813b23d..c871120e36 100644
--- a/bin/tests/system/statschannel/tests.sh
+++ b/bin/tests/system/statschannel/tests.sh
@@ -18,7 +18,7 @@ set -e
 
 DIGCMD="$DIG @10.53.0.2 -p ${PORT}"
 RNDCCMD="$RNDC -c ../_common/rndc.conf -p ${CONTROLPORT} -s"
-NS_PARAMS="-m record -c named.conf -d 99 -g -U 4 -T maxcachesize=2097152"
+NS_PARAMS="-m record -c named.conf -d 99 -g -T maxcachesize=2097152"
 
 if ! $FEATURETEST --have-json-c; then
   unset PERL_JSON
diff --git a/bin/tests/system/xfer/ns6/named.args b/bin/tests/system/xfer/ns6/named.args
index 7580d15297..96034b5641 100644
--- a/bin/tests/system/xfer/ns6/named.args
+++ b/bin/tests/system/xfer/ns6/named.args
@@ -1 +1 @@
--D xfer-ns6 -m record -c named.conf -d 99 -g -U 4 -T maxcachesize=2097152 -T transferinsecs
+-D xfer-ns6 -m record -c named.conf -d 99 -g -T maxcachesize=2097152 -T transferinsecs
diff --git a/bin/tests/system/xfer/tests.sh b/bin/tests/system/xfer/tests.sh
index 01427a2a4d..76b51dfd6b 100755
--- a/bin/tests/system/xfer/tests.sh
+++ b/bin/tests/system/xfer/tests.sh
@@ -17,7 +17,7 @@ set -e
 
 DIGOPTS="+tcp +noadd +nosea +nostat +noquest +nocomm +nocmd -p ${PORT}"
 RNDCCMD="$RNDC -c ../_common/rndc.conf -p ${CONTROLPORT} -s"
-NS_PARAMS="-m record -c named.conf -d 99 -g -U 4 -T maxcachesize=2097152"
+NS_PARAMS="-m record -c named.conf -d 99 -g -T maxcachesize=2097152"
 
 status=0
 n=0