diff --git a/net/adc_device_netserver.h b/net/adc_device_netserver.h
index 78950ad..4b0cb1c 100644
--- a/net/adc_device_netserver.h
+++ b/net/adc_device_netserver.h
@@ -344,7 +344,8 @@ public:
                             }
                         }
                         if (found) {
-                            msg.ack(msg_t::DEVICE_KEY, attrs);
+                            // msg.ack(msg_t::DEVICE_KEY, attrs);
+                            msg.ack(constants::ADC_DEVICE_NETPROTO_KEY_DEVICE, attrs);
                         } else {
                             msg.err(std::make_error_code(AdcDeviceNetServerSessionError::ERROR_UNKNOWN_DEVICE_ID));
                         }
@@ -356,14 +357,17 @@ public:
                     for (auto& [ptr, dev_wr] : _serverPtr->_devices) {
                         names.emplace_back(dev_wr.ident());
                     }
-                    msg.ack(msg_t::NAMES_KEY, names);
+                    // msg.ack(msg_t::NAMES_KEY, names);
+                    msg.ack(constants::ADC_DEVICE_NETPROTO_KEY_NAMES, names);
                 } else if (msg.isHELLO()) {
-                    msg.ack(msg_t::HELLO_KEY, _serverPtr->_serverIdent);
+                    // msg.ack(msg_t::HELLO_KEY, _serverPtr->_serverIdent);
+                    msg.ack(constants::ADC_DEVICE_NETPROTO_KEY_HELLO, _serverPtr->_serverIdent);
                 } else if (msg.isGET()) {  // get attribute value
                     attrs = msg.template attrs<attr_vec_t>(0, 1);
                     if (attrs.size()) {
                         auto val = _bindDevice->getAttr(get_elem(0));
-                        msg.ack(msg_t::GET_KEY, get_elem(0), val);
+                        // msg.ack(msg_t::GET_KEY, get_elem(0), val);
+                        msg.ack(constants::ADC_DEVICE_NETPROTO_KEY_GET, get_elem(0), val);
                     } else {  // no attr name!
                         msg.err(std::make_error_code(AdcDeviceNetServerSessionError::ERROR_NO_PROTO_ATTRNAME));
                     }
@@ -372,7 +376,8 @@ public:
                     if (attrs.size() >= 2) {
                         auto val = msg.template joinAttrs<serialized_t>(1);
                         _bindDevice->setAttr(get_elem(0), val);
-                        msg.ack(msg_t::SET_KEY, get_elem(0), val);
+                        // msg.ack(msg_t::SET_KEY, get_elem(0), val);
+                        msg.ack(constants::ADC_DEVICE_NETPROTO_KEY_SET, get_elem(0), val);
                     } else {  // no attr name or its value!
                         if (attrs.size() == 1) {
                             msg.err(std::make_error_code(AdcDeviceNetServerSessionError::ERROR_NO_PROTO_ATTRVALUE));
@@ -385,7 +390,8 @@ public:
                     if (attrs.size()) {
                         auto cmd_name = get_elem(0);
                         _bindDevice->exec(cmd_name);
-                        msg.ack(msg_t::CMD_KEY, cmd_name);
+                        // msg.ack(msg_t::CMD_KEY, cmd_name);
+                        msg.ack(constants::ADC_DEVICE_NETPROTO_KEY_CMD, cmd_name);
                     } else {  // no cmd name!
                         msg.err(std::make_error_code(AdcDeviceNetServerSessionError::ERROR_NO_PROTO_CMDNAME));
                     }
diff --git a/net/adc_endpoint.h b/net/adc_endpoint.h
index 4f79844..7516125 100644
--- a/net/adc_endpoint.h
+++ b/net/adc_endpoint.h
@@ -304,6 +304,36 @@ public:
         return proto() == protoMarkWSS;
     }
 
+    // add '\0' char (or replace special-meaning char/char-sequence) to construct UNIX abstract namespace
+    // endpoint path
+    template <typename T = std::nullptr_t>
+    AdcEndpoint& makeAbstract(const T& mark = nullptr)
+        requires(traits::adc_input_char_range<T> || std::same_as<std::remove_cv_t<T>, char> ||
+                 std::is_null_pointer_v<std::remove_cv_t<T>>)
+    {
+        if (!(isLocalStream() || isLocalSeqpacket())) {  // only local proto is valid!
+            return *this;
+        }
+
+        if constexpr (std::is_null_pointer_v<T>) {  // just insert '\0'
+            auto it = _endpoint.insert(std::string::const_iterator(_path.begin()), '\0');
+            _path = std::string_view(it, _endpoint.end());
+        } else if constexpr (std::same_as<std::remove_cv_t<T>, char>) {  // replace a character (mark)
+            auto pos = std::distance(_endpoint.cbegin(), std::string::const_iterator(_path.begin()));
+            if (_endpoint[pos] == mark) {
+                _endpoint[pos] = '\0';
+            }
+        } else {  // replace a character range (mark)
+            if (std::ranges::equal(_path | std::views::take(std::ranges::size(mark), mark))) {
+                auto pos = std::distance(_endpoint.cbegin(), std::string::const_iterator(_path.begin()));
+                _endpoint.replace(pos, std::ranges::size(mark), 1, '\0');
+                _path = std::string_view(_endpoint.begin() + pos, _endpoint.end());
+            }
+        }
+
+        return *this;
+    }
+
 protected:
     std::string _endpoint;
     std::string_view _proto, _host, _path, _portView;
diff --git a/tests/adc_asio_netserver_test.cpp b/tests/adc_asio_netserver_test.cpp
index b3adf3a..8fe2c3d 100644
--- a/tests/adc_asio_netserver_test.cpp
+++ b/tests/adc_asio_netserver_test.cpp
@@ -162,13 +162,14 @@ int main(int argc, char* argv[])
         for (auto& ep : epnt) {
             adc::AdcEndpoint epn(ep);
             if (epn.isValid()) {
-                if (epn.isLocalSeqpacket() || epn.isLocalStream()) {
-                    if (epn.path()[0] == '@') {  // replace '@' to '\0' (use of UNIX abstract namespace)
-                        auto it = std::ranges::find(ep, '@');
-                        *it = '\0';
-                        epn = adc::AdcEndpoint(ep);
-                    }
-                }
+                epn.makeAbstract('@');
+                // if (epn.isLocalSeqpacket() || epn.isLocalStream()) {
+                //     if (epn.path()[0] == '@') {  // replace '@' to '\0' (use of UNIX abstract namespace)
+                //         auto it = std::ranges::find(ep, '@');
+                //         *it = '\0';
+                //         epn = adc::AdcEndpoint(ep);
+                //     }
+                // }
 
                 // std::cout << "try to start listenning at '" << ep << "' ...";