diff --git a/src/fuzzers/FuzzBuffer.cc b/src/fuzzers/FuzzBuffer.cc
index 866b63bb20..ebae1a1db1 100644
--- a/src/fuzzers/FuzzBuffer.cc
+++ b/src/fuzzers/FuzzBuffer.cc
@@ -6,7 +6,7 @@
 
 #include "FuzzBuffer.h"
 
-bool zeek::FuzzBuffer::Valid() const
+bool zeek::detail::FuzzBuffer::Valid() const
 	{
 	if ( end - begin < PKT_MAGIC_LEN + 2 )
 		return false;
@@ -17,7 +17,7 @@ bool zeek::FuzzBuffer::Valid() const
 	return true;
 	}
 
-std::optional<zeek::FuzzBuffer::Chunk> zeek::FuzzBuffer::Next()
+std::optional<zeek::detail::FuzzBuffer::Chunk> zeek::detail::FuzzBuffer::Next()
 	{
 	if ( begin == end )
 		return {};
diff --git a/src/fuzzers/FuzzBuffer.h b/src/fuzzers/FuzzBuffer.h
index 81770857e6..1b9cdb58a3 100644
--- a/src/fuzzers/FuzzBuffer.h
+++ b/src/fuzzers/FuzzBuffer.h
@@ -4,7 +4,7 @@
 #include <memory>
 #include <optional>
 
-namespace zeek {
+namespace zeek { namespace detail {
 
 /**
  * This structure helps chunk/simulate protocol conversions from arbitrary
@@ -54,4 +54,4 @@ private:
 	const unsigned char* end;
 };
 
-} // namespace zeek
+}} // namespace zeek::detail
diff --git a/src/fuzzers/fuzzer-setup.h b/src/fuzzers/fuzzer-setup.h
index c8714f0ac2..e692ddd3c4 100644
--- a/src/fuzzers/fuzzer-setup.h
+++ b/src/fuzzers/fuzzer-setup.h
@@ -36,15 +36,15 @@ extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv)
 	options.ignore_checksums = true;
 	options.abort_on_scripting_errors = true;
 
-	if ( zeek::setup(*argc, *argv, &options).code )
+	if ( zeek::detail::setup(*argc, *argv, &options).code )
 		abort();
 
 	return 0;
 	}
 
-namespace zeek {
+namespace zeek { namespace detail {
 
-void fuzz_cleanup_one_input()
+void fuzzer_cleanup_one_input()
 	{
 	terminating = true;
 	broker_mgr->ClearStores();
@@ -58,4 +58,4 @@ void fuzz_cleanup_one_input()
 	terminating = false;
 	}
 
-} // namespace zeek
+}} // namespace zeek::detail
diff --git a/src/fuzzers/pop3-fuzzer.cc b/src/fuzzers/pop3-fuzzer.cc
index 394a6f508a..5cc4776aad 100644
--- a/src/fuzzers/pop3-fuzzer.cc
+++ b/src/fuzzers/pop3-fuzzer.cc
@@ -45,7 +45,7 @@ static analyzer::Analyzer* add_analyzer(Connection* conn)
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
 	{
-	zeek::FuzzBuffer fb{data, size};
+	zeek::detail::FuzzBuffer fb{data, size};
 
 	if ( ! fb.Valid() )
 		return 0;
@@ -72,6 +72,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
 		mgr.Drain();
 		}
 
-	zeek::fuzz_cleanup_one_input();
+	zeek::detail::fuzzer_cleanup_one_input();
 	return 0;
 	}
diff --git a/src/main.cc b/src/main.cc
index 7d7e876f41..b107dd213c 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -10,7 +10,7 @@
 int main(int argc, char** argv)
 	{
 	auto time_start = current_time(true);
-	auto setup_result = zeek::setup(argc, argv);
+	auto setup_result = zeek::detail::setup(argc, argv);
 
 	if ( setup_result.code )
 		return setup_result.code;
@@ -78,5 +78,5 @@ int main(int argc, char** argv)
 			}
 		}
 
-	return zeek::cleanup(do_net_run);
+	return zeek::detail::cleanup(do_net_run);
 	}
diff --git a/src/zeek-setup.cc b/src/zeek-setup.cc
index 25251d4555..34ff4a7609 100644
--- a/src/zeek-setup.cc
+++ b/src/zeek-setup.cc
@@ -374,7 +374,8 @@ static std::vector<std::string> get_script_signature_files()
 	return rval;
 	}
 
-zeek::SetupResult zeek::setup(int argc, char** argv, zeek::Options* zopts)
+zeek::detail::SetupResult zeek::detail::setup(int argc, char** argv,
+                                              zeek::Options* zopts)
 	{
 	ZEEK_LSAN_DISABLE();
 	std::set_new_handler(bro_new_handler);
@@ -866,7 +867,7 @@ zeek::SetupResult zeek::setup(int argc, char** argv, zeek::Options* zopts)
 	return {0, std::move(options)};
 	}
 
-int zeek::cleanup(bool did_net_run)
+int zeek::detail::cleanup(bool did_net_run)
 	{
 	if ( did_net_run )
 		done_with_network();
diff --git a/src/zeek-setup.h b/src/zeek-setup.h
index 303ded4abd..22cb85fde7 100644
--- a/src/zeek-setup.h
+++ b/src/zeek-setup.h
@@ -4,7 +4,7 @@
 
 #include "Options.h"
 
-namespace zeek {
+namespace zeek { namespace detail {
 
 struct SetupResult {
 	int code = 0;
@@ -28,4 +28,4 @@ SetupResult setup(int argc, char** argv, zeek::Options* options = nullptr);
  */
 int cleanup(bool did_net_run);
 
-}
+}} // namespace zeek::detail