diff --git a/tests/run-tests.sh b/tests/run-tests.sh
index f8294fca..f3351775 100755
--- a/tests/run-tests.sh
+++ b/tests/run-tests.sh
@@ -90,6 +90,7 @@ done
 # set some T_ defaults
 T_TRACE_DUMP="0"
 T_TRACE_PRINTK="0"
+T_PORT_START="19700"
 
 # array declarations to be able to use array ops
 declare -a T_TRACE_GLOB
@@ -265,6 +266,17 @@ for e in T_META_DEVICE T_DATA_DEVICE T_EX_META_DEV T_EX_DATA_DEV T_KMOD T_RESULT
 	eval $e=\"$(readlink -f "${!e}")\"
 done
 
+# try and check ports, but not necessary
+T_TEST_PORT="$T_PORT_START"
+T_SCRATCH_PORT="$((T_PORT_START + 100))"
+T_DEV_PORT="$((T_PORT_START + 200))"
+read local_start local_end < /proc/sys/net/ipv4/ip_local_port_range
+if [ -n "$local_start" -a -n "$local_end" -a "$local_start" -lt "$local_end" ]; then
+	if [ ! "$T_DEV_PORT" -lt "$local_start" -a ! "$T_TEST_PORT" -gt "$local_end" ]; then
+		die "listening port range $T_TEST_PORT - $T_DEV_PORT is within local dynamic port range $local_start - $local_end in /proc/sys/net/ipv4/ip_local_port_range"
+	fi
+fi
+
 # permute sequence?
 T_SEQUENCE=sequence
 if [ -n "$T_SHUF" ]; then
@@ -363,7 +375,7 @@ fi
 quo=""
 if [ -n "$T_MKFS" ]; then
 	for i in $(seq -0 $((T_QUORUM - 1))); do
-		quo="$quo -Q $i,127.0.0.1,$((42000 + i))"
+		quo="$quo -Q $i,127.0.0.1,$((T_TEST_PORT + i))"
 	done
 
 	msg "making new filesystem with $T_QUORUM quorum members"
diff --git a/tests/tests/basic-bad-mounts.sh b/tests/tests/basic-bad-mounts.sh
index b8710b04..d8bc13ef 100644
--- a/tests/tests/basic-bad-mounts.sh
+++ b/tests/tests/basic-bad-mounts.sh
@@ -15,7 +15,7 @@ echo "== prepare devices, mount point, and logs"
 SCR="$T_TMPDIR/mnt.scratch"
 mkdir -p "$SCR"
 > $T_TMP.mount.out
-scoutfs mkfs -f -Q 0,127.0.0.1,53000 "$T_EX_META_DEV" "$T_EX_DATA_DEV" > $T_TMP.mkfs.out 2>&1 \
+scoutfs mkfs -f -Q 0,127.0.0.1,$T_SCRATCH_PORT "$T_EX_META_DEV" "$T_EX_DATA_DEV" > $T_TMP.mkfs.out 2>&1 \
 	|| t_fail "mkfs failed"
 
 echo "== bad devices, bad options"
diff --git a/tests/tests/change-devices.sh b/tests/tests/change-devices.sh
index cb1e34cd..2436c5fa 100644
--- a/tests/tests/change-devices.sh
+++ b/tests/tests/change-devices.sh
@@ -11,7 +11,7 @@ truncate -s $sz "$T_TMP.equal"
 truncate -s $large_sz "$T_TMP.large"
 
 echo "== make scratch fs"
-t_quiet scoutfs mkfs -f -Q 0,127.0.0.1,53000 "$T_EX_META_DEV" "$T_EX_DATA_DEV"
+t_quiet scoutfs mkfs -f -Q 0,127.0.0.1,$T_SCRATCH_PORT "$T_EX_META_DEV" "$T_EX_DATA_DEV"
 SCR="$T_TMPDIR/mnt.scratch"
 mkdir -p "$SCR"
 
diff --git a/tests/tests/enospc.sh b/tests/tests/enospc.sh
index f3ade8f0..3f4cc1cd 100644
--- a/tests/tests/enospc.sh
+++ b/tests/tests/enospc.sh
@@ -57,7 +57,7 @@ test "$before" == "$after" || \
 # XXX this is all pretty manual, would be nice to have helpers
 echo "== make small meta fs"
 # meta device just big enough for reserves and the metadata we'll fill
-scoutfs mkfs -A -f -Q 0,127.0.0.1,53000 -m 10G "$T_EX_META_DEV" "$T_EX_DATA_DEV" > $T_TMP.mkfs.out 2>&1 || \
+scoutfs mkfs -A -f -Q 0,127.0.0.1,$T_SCRATCH_PORT -m 10G "$T_EX_META_DEV" "$T_EX_DATA_DEV" > $T_TMP.mkfs.out 2>&1 || \
 	t_fail "mkfs failed"
 SCR="$T_TMPDIR/mnt.scratch"
 mkdir -p "$SCR"
diff --git a/tests/tests/format-version-forward-back.sh b/tests/tests/format-version-forward-back.sh
index 04d6f907..d907ef49 100644
--- a/tests/tests/format-version-forward-back.sh
+++ b/tests/tests/format-version-forward-back.sh
@@ -89,7 +89,7 @@ for vers in $(seq $MIN $((MAX - 1))); do
 	old_module="$builds/$vers/scoutfs.ko"
 
 	echo "mkfs $vers" >> "$T_TMP.log"
-	t_quiet $old_scoutfs mkfs -f -Q 0,127.0.0.1,53000 "$T_EX_META_DEV" "$T_EX_DATA_DEV" \
+	t_quiet $old_scoutfs mkfs -f -Q 0,127.0.0.1,$T_SCRATCH_PORT "$T_EX_META_DEV" "$T_EX_DATA_DEV" \
 		|| t_fail "mkfs $vers failed"
 
 	echo "mount $vers with $vers" >> "$T_TMP.log"
diff --git a/tests/tests/resize-devices.sh b/tests/tests/resize-devices.sh
index 3b13accf..cceda43c 100644
--- a/tests/tests/resize-devices.sh
+++ b/tests/tests/resize-devices.sh
@@ -72,7 +72,7 @@ quarter_data=$(echo "$size_data / 4" | bc)
 
 # XXX this is all pretty manual, would be nice to have helpers
 echo "== make initial small fs"
-scoutfs mkfs -A -f -Q 0,127.0.0.1,53000 -m $quarter_meta -d $quarter_data \
+scoutfs mkfs -A -f -Q 0,127.0.0.1,$T_SCRATCH_PORT -m $quarter_meta -d $quarter_data \
 	"$T_EX_META_DEV" "$T_EX_DATA_DEV" > $T_TMP.mkfs.out 2>&1 || \
 		t_fail "mkfs failed"
 SCR="$T_TMPDIR/mnt.scratch"
diff --git a/tests/tests/xfstests.sh b/tests/tests/xfstests.sh
index b0ae44cf..bd02a1a3 100644
--- a/tests/tests/xfstests.sh
+++ b/tests/tests/xfstests.sh
@@ -50,9 +50,9 @@ t_quiet sync
 cat << EOF > local.config
 export FSTYP=scoutfs
 export MKFS_OPTIONS="-f"
-export MKFS_TEST_OPTIONS="-Q 0,127.0.0.1,42000"
-export MKFS_SCRATCH_OPTIONS="-Q 0,127.0.0.1,43000"
-export MKFS_DEV_OPTIONS="-Q 0,127.0.0.1,44000"
+export MKFS_TEST_OPTIONS="-Q 0,127.0.0.1,$T_TEST_PORT"
+export MKFS_SCRATCH_OPTIONS="-Q 0,127.0.0.1,$T_SCRATCH_PORT"
+export MKFS_DEV_OPTIONS="-Q 0,127.0.0.1,$T_DEV_PORT"
 export TEST_DEV=$T_DB0
 export TEST_DIR=$T_M0
 export SCRATCH_META_DEV=$T_EX_META_DEV