diff --git a/src/net/tools/naive/naive_connection.cc b/src/net/tools/naive/naive_connection.cc
index 339990beb0..a2e51c9fc2 100644
--- a/src/net/tools/naive/naive_connection.cc
+++ b/src/net/tools/naive/naive_connection.cc
@@ -55,6 +55,7 @@ NaiveConnection::NaiveConnection(
     const SSLConfig& proxy_ssl_config,
     RedirectResolver* resolver,
     HttpNetworkSession* session,
+    const NetworkIsolationKey& network_isolation_key,
     const NetLogWithSource& net_log,
     std::unique_ptr<StreamSocket> accepted_socket,
     const NetworkTrafficAnnotationTag& traffic_annotation)
@@ -66,6 +67,7 @@ NaiveConnection::NaiveConnection(
       proxy_ssl_config_(proxy_ssl_config),
       resolver_(resolver),
       session_(session),
+      network_isolation_key_(network_isolation_key),
       net_log_(net_log),
       next_state_(STATE_NONE),
       client_socket_(std::move(accepted_socket)),
@@ -239,8 +241,9 @@ int NaiveConnection::DoConnectServer() {
   // Ignores socket limit set by socket pool for this type of socket.
   return InitSocketHandleForRawConnect2(
       origin, session_, LOAD_IGNORE_LIMITS, MAXIMUM_PRIORITY, proxy_info_,
-      server_ssl_config_, proxy_ssl_config_, PRIVACY_MODE_DISABLED, net_log_,
-      server_socket_handle_.get(), io_callback_);
+      server_ssl_config_, proxy_ssl_config_, PRIVACY_MODE_DISABLED,
+      network_isolation_key_, net_log_, server_socket_handle_.get(),
+      io_callback_);
 }
 
 int NaiveConnection::DoConnectServerComplete(int result) {
diff --git a/src/net/tools/naive/naive_connection.h b/src/net/tools/naive/naive_connection.h
index ef9c7f8f11..d4a26e8641 100644
--- a/src/net/tools/naive/naive_connection.h
+++ b/src/net/tools/naive/naive_connection.h
@@ -28,6 +28,7 @@ class StreamSocket;
 struct NetworkTrafficAnnotationTag;
 struct SSLConfig;
 class RedirectResolver;
+class NetworkIsolationKey;
 
 class NaiveConnection {
  public:
@@ -55,6 +56,7 @@ class NaiveConnection {
                   const SSLConfig& proxy_ssl_config,
                   RedirectResolver* resolver,
                   HttpNetworkSession* session,
+                  const NetworkIsolationKey& network_isolation_key,
                   const NetLogWithSource& net_log,
                   std::unique_ptr<StreamSocket> accepted_socket,
                   const NetworkTrafficAnnotationTag& traffic_annotation);
@@ -107,6 +109,7 @@ class NaiveConnection {
   const SSLConfig& proxy_ssl_config_;
   RedirectResolver* resolver_;
   HttpNetworkSession* session_;
+  const NetworkIsolationKey& network_isolation_key_;
   const NetLogWithSource& net_log_;
 
   CompletionRepeatingCallback io_callback_;
diff --git a/src/net/tools/naive/naive_proxy.cc b/src/net/tools/naive/naive_proxy.cc
index aeef545e0d..097d357a15 100644
--- a/src/net/tools/naive/naive_proxy.cc
+++ b/src/net/tools/naive/naive_proxy.cc
@@ -5,6 +5,7 @@
 
 #include "net/tools/naive/naive_proxy.h"
 
+#include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ -28,12 +29,14 @@ namespace net {
 NaiveProxy::NaiveProxy(std::unique_ptr<ServerSocket> listen_socket,
                        NaiveConnection::Protocol protocol,
                        bool use_padding,
+                       int concurrency,
                        RedirectResolver* resolver,
                        HttpNetworkSession* session,
                        const NetworkTrafficAnnotationTag& traffic_annotation)
     : listen_socket_(std::move(listen_socket)),
       protocol_(protocol),
       use_padding_(use_padding),
+      concurrency_(std::min(4, std::max(1, concurrency))),
       resolver_(resolver),
       session_(session),
       net_log_(
@@ -54,6 +57,10 @@ NaiveProxy::NaiveProxy(std::unique_ptr<ServerSocket> listen_socket,
   session_->GetSSLConfig(&server_ssl_config_, &proxy_ssl_config_);
   proxy_ssl_config_.disable_cert_verification_network_fetches = true;
 
+  for (int i = 0; i < concurrency_; i++) {
+    network_isolation_keys_.push_back(NetworkIsolationKey::CreateTransient());
+  }
+
   DCHECK(listen_socket_);
   // Start accepting connections in next run loop in case when delegate is not
   // ready to get callbacks.
@@ -110,9 +117,11 @@ void NaiveProxy::DoConnect() {
   if (!use_padding_) {
     pad_direction = NaiveConnection::kNone;
   }
+  last_id_++;
+  const auto& nik = network_isolation_keys_[last_id_ % concurrency_];
   auto connection_ptr = std::make_unique<NaiveConnection>(
-      ++last_id_, protocol_, pad_direction, proxy_info_, server_ssl_config_,
-      proxy_ssl_config_, resolver_, session_, net_log_, std::move(socket),
+      last_id_, protocol_, pad_direction, proxy_info_, server_ssl_config_,
+      proxy_ssl_config_, resolver_, session_, nik, net_log_, std::move(socket),
       traffic_annotation_);
   auto* connection = connection_ptr.get();
   connection_by_id_[connection->id()] = std::move(connection_ptr);
diff --git a/src/net/tools/naive/naive_proxy.h b/src/net/tools/naive/naive_proxy.h
index fbae124249..de7535483f 100644
--- a/src/net/tools/naive/naive_proxy.h
+++ b/src/net/tools/naive/naive_proxy.h
@@ -8,10 +8,12 @@
 
 #include <map>
 #include <memory>
+#include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "net/base/completion_repeating_callback.h"
+#include "net/base/network_isolation_key.h"
 #include "net/log/net_log_with_source.h"
 #include "net/proxy_resolution/proxy_info.h"
 #include "net/ssl/ssl_config.h"
@@ -32,6 +34,7 @@ class NaiveProxy {
   NaiveProxy(std::unique_ptr<ServerSocket> server_socket,
              NaiveConnection::Protocol protocol,
              bool use_padding,
+             int concurrency,
              RedirectResolver* resolver,
              HttpNetworkSession* session,
              const NetworkTrafficAnnotationTag& traffic_annotation);
@@ -57,6 +60,7 @@ class NaiveProxy {
   std::unique_ptr<ServerSocket> listen_socket_;
   NaiveConnection::Protocol protocol_;
   bool use_padding_;
+  int concurrency_;
   ProxyInfo proxy_info_;
   SSLConfig server_ssl_config_;
   SSLConfig proxy_ssl_config_;
@@ -68,6 +72,8 @@ class NaiveProxy {
 
   std::unique_ptr<StreamSocket> accepted_socket_;
 
+  std::vector<NetworkIsolationKey> network_isolation_keys_;
+
   std::map<unsigned int, std::unique_ptr<NaiveConnection>> connection_by_id_;
 
   const NetworkTrafficAnnotationTag& traffic_annotation_;
diff --git a/src/net/tools/naive/naive_proxy_bin.cc b/src/net/tools/naive/naive_proxy_bin.cc
index d4b071df3b..30414deacf 100644
--- a/src/net/tools/naive/naive_proxy_bin.cc
+++ b/src/net/tools/naive/naive_proxy_bin.cc
@@ -11,6 +11,7 @@
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
+#include "base/feature_list.h"
 #include "base/files/file_path.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/json/json_writer.h"
@@ -80,6 +81,7 @@ struct CommandLine {
   std::string listen;
   std::string proxy;
   bool padding;
+  std::string concurrency;
   std::string extra_headers;
   std::string host_resolver_rules;
   std::string resolver_range;
@@ -94,6 +96,7 @@ struct Params {
   std::string listen_addr;
   int listen_port;
   bool use_padding;
+  int concurrency;
   net::HttpRequestHeaders extra_headers;
   std::string proxy_url;
   std::string proxy_user;
@@ -141,6 +144,7 @@ void GetCommandLine(const base::CommandLine& proc, CommandLine* cmdline) {
                  "--proxy=<proto>://[<user>:<pass>@]<hostname>[:<port>]\n"
                  "                           proto: https, quic\n"
                  "--padding                  Use padding\n"
+                 "--concurrency=<N>          Use N connections, less secure\n"
                  "--extra-headers=...        Extra headers split by CRLF\n"
                  "--host-resolver-rules=...  Resolver rules\n"
                  "--resolver-range=...       Redirect resolver range\n"
@@ -159,6 +163,7 @@ void GetCommandLine(const base::CommandLine& proc, CommandLine* cmdline) {
   cmdline->listen = proc.GetSwitchValueASCII("listen");
   cmdline->proxy = proc.GetSwitchValueASCII("proxy");
   cmdline->padding = proc.HasSwitch("padding");
+  cmdline->concurrency = proc.GetSwitchValueASCII("concurrency");
   cmdline->extra_headers = proc.GetSwitchValueASCII("extra-headers");
   cmdline->host_resolver_rules =
       proc.GetSwitchValueASCII("host-resolver-rules");
@@ -193,6 +198,10 @@ void GetCommandLineFromConfig(const base::FilePath& config_path,
     cmdline->proxy = *proxy;
   }
   cmdline->padding = value->FindBoolKey("padding").value_or(false);
+  const auto* concurrency = value->FindStringKey("concurrency");
+  if (concurrency) {
+    cmdline->concurrency = *concurrency;
+  }
   const auto* extra_headers = value->FindStringKey("extra_headers");
   if (extra_headers) {
     cmdline->extra_headers = *extra_headers;
@@ -292,6 +301,16 @@ bool ParseCommandLine(const CommandLine& cmdline, Params* params) {
 
   params->use_padding = cmdline.padding;
 
+  if (!cmdline.concurrency.empty()) {
+    if (!base::StringToInt(cmdline.concurrency, &params->concurrency) ||
+        params->concurrency < 1 || params->concurrency > 4) {
+      std::cerr << "Invalid concurrency" << std::endl;
+      return false;
+    }
+  } else {
+    params->concurrency = 1;
+  }
+
   params->extra_headers.AddHeadersFromString(cmdline.extra_headers);
 
   params->host_resolver_rules = cmdline.host_resolver_rules;
@@ -475,6 +494,8 @@ std::unique_ptr<URLRequestContext> BuildURLRequestContext(
 }  // namespace net
 
 int main(int argc, char* argv[]) {
+  base::FeatureList::InitializeInstance(
+      "PartitionConnectionsByNetworkIsolationKey", std::string());
   base::SingleThreadTaskExecutor io_task_executor(base::MessagePumpType::IO);
   base::ThreadPoolInstance::CreateAndStartWithDefaultParams("naive");
   base::AtExitManager exit_manager;
@@ -589,8 +610,8 @@ int main(int argc, char* argv[]) {
   }
 
   net::NaiveProxy naive_proxy(std::move(listen_socket), params.protocol,
-                              params.use_padding, resolver.get(), session,
-                              kTrafficAnnotation);
+                              params.use_padding, params.concurrency,
+                              resolver.get(), session, kTrafficAnnotation);
 
   base::RunLoop().Run();