diff --git a/bin/tests/system/dnstap/prereq.sh b/bin/tests/system/dnstap/prereq.sh
deleted file mode 100644
index 747f448982..0000000000
--- a/bin/tests/system/dnstap/prereq.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/bin/sh
-
-# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
-#
-# SPDX-License-Identifier: MPL-2.0
-#
-# 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 https://mozilla.org/MPL/2.0/.
-#
-# See the COPYRIGHT file distributed with this work for additional
-# information regarding copyright ownership.
-
-. ../conf.sh
-
-$FEATURETEST --enable-dnstap || {
-  echo_i "This test requires dnstap support." >&2
-  exit 255
-}
-exit 0
diff --git a/bin/tests/system/dnstap/tests_dnstap.py b/bin/tests/system/dnstap/tests_dnstap.py
index 6326ef06f8..258d2b5f89 100644
--- a/bin/tests/system/dnstap/tests_dnstap.py
+++ b/bin/tests/system/dnstap/tests_dnstap.py
@@ -13,35 +13,38 @@
 
 import os
 import re
-import subprocess
 
 import isctest
+import isctest.mark
 import pytest
 
 import dns.message
 
 pytest.importorskip("dns", minversion="2.0.0")
 
-pytestmark = pytest.mark.extra_artifacts(
-    [
-        "dnstap.out.*",
-        "ns*/dnstap.out*",
-        "ns2/example.db",
-    ]
-)
+pytestmark = [
+    isctest.mark.with_dnstap,
+    pytest.mark.extra_artifacts(
+        [
+            "dnstap.out.*",
+            "ns*/dnstap.out*",
+            "ns2/example.db",
+        ]
+    ),
+]
 
 
 def run_rndc(server, rndc_command):
     """
     Send the specified 'rndc_command' to 'server' with a timeout of 10 seconds
     """
-    rndc = os.getenv("RNDC")
-    port = os.getenv("CONTROLPORT")
+    rndc = isctest.vars.ALL["RNDC"]
+    port = isctest.vars.ALL["CONTROLPORT"]
 
     cmdline = [rndc, "-c", "../_common/rndc.conf", "-p", port, "-s", server]
     cmdline.extend(rndc_command)
 
-    subprocess.check_output(cmdline, stderr=subprocess.STDOUT, timeout=10)
+    isctest.run.cmd(cmdline, log_stdout=True)
 
 
 def test_dnstap_dispatch_socket_addresses():
@@ -59,8 +62,9 @@ def test_dnstap_dispatch_socket_addresses():
     os.rename(os.path.join("ns3", "dnstap.out.0"), "dnstap.out.resolver_addresses")
 
     # Read the contents of the dnstap file using dnstap-read.
-    output = subprocess.check_output(
-        [os.getenv("DNSTAPREAD"), "dnstap.out.resolver_addresses"], encoding="utf-8"
+    run = isctest.run.cmd(
+        [isctest.vars.ALL["DNSTAPREAD"], "dnstap.out.resolver_addresses"],
+        log_stdout=True,
     )
 
     # Check whether all frames contain the expected addresses.
@@ -75,7 +79,7 @@ def test_dnstap_dispatch_socket_addresses():
     bad_frames = []
     inspected_frames = 0
     addr_regex = r"^10\.53\.0\.[0-9]+:[0-9]{1,5}$"
-    for line in output.splitlines():
+    for line in run.stdout.decode("utf-8").splitlines():
         _, _, frame_type, addr1, _, addr2, _ = line.split(" ", 6)
         # Only inspect RESOLVER_QUERY and RESOLVER_RESPONSE frames.
         if frame_type not in ("RQ", "RR"):
diff --git a/bin/tests/system/dnstap/tests_sh_dnstap.py b/bin/tests/system/dnstap/tests_sh_dnstap.py
index 5d4d7a9e9e..10d9a4111b 100644
--- a/bin/tests/system/dnstap/tests_sh_dnstap.py
+++ b/bin/tests/system/dnstap/tests_sh_dnstap.py
@@ -11,19 +11,24 @@
 
 import pytest
 
-pytestmark = pytest.mark.extra_artifacts(
-    [
-        "dig.out*",
-        "dnstap.hex*",
-        "dnstap.out*",
-        "fstrm_capture.out.*",
-        "nsupdate.out*",
-        "ydump.out*",
-        "ns*/dnstap.out*",
-        "ns2/example.db",
-        "ns2/example.db.jnl",
-    ]
-)
+import isctest.mark
+
+pytestmark = [
+    isctest.mark.with_dnstap,
+    pytest.mark.extra_artifacts(
+        [
+            "dig.out*",
+            "dnstap.hex*",
+            "dnstap.out*",
+            "fstrm_capture.out.*",
+            "nsupdate.out*",
+            "ydump.out*",
+            "ns*/dnstap.out*",
+            "ns2/example.db",
+            "ns2/example.db.jnl",
+        ]
+    ),
+]
 
 
 def test_dnstap(run_tests_sh):
diff --git a/bin/tests/system/isctest/mark.py b/bin/tests/system/isctest/mark.py
index 9b193c8fe5..3bd1e6816e 100644
--- a/bin/tests/system/isctest/mark.py
+++ b/bin/tests/system/isctest/mark.py
@@ -34,10 +34,6 @@ def feature_test(feature):
     return True
 
 
-def with_dnstap(*args):  # pylint: disable=unused-argument
-    return feature_test("--enable-dnstap")
-
-
 def with_tsan(*args):  # pylint: disable=unused-argument
     return feature_test("--tsan")
 
@@ -48,6 +44,11 @@ def with_algorithm(name: str):
     return pytest.mark.skipif(os.getenv(key) != "1", reason=f"{name} is not supported")
 
 
+with_dnstap = pytest.mark.skipif(
+    not feature_test("--enable-dnstap"), reason="DNSTAP support disabled in the build"
+)
+
+
 without_fips = pytest.mark.skipif(
     feature_test("--have-fips-mode"), reason="FIPS support enabled in the build"
 )