diff --git a/src/null_mechanism.cpp b/src/null_mechanism.cpp
index 070f76eb..de546de4 100644
--- a/src/null_mechanism.cpp
+++ b/src/null_mechanism.cpp
@@ -28,13 +28,25 @@
 
 #include "err.hpp"
 #include "msg.hpp"
+#include "session_base.hpp"
 #include "wire.hpp"
 #include "null_mechanism.hpp"
 
-zmq::null_mechanism_t::null_mechanism_t (const options_t &options_) : mechanism_t (options_),
-  ready_command_sent (false),
-  ready_command_received (false)
+zmq::null_mechanism_t::null_mechanism_t (session_base_t *session_,
+                                         const std::string &peer_address_,
+                                         const options_t &options_) :
+    mechanism_t (options_),
+    session (session_),
+    peer_address (peer_address_),
+    ready_command_sent (false),
+    ready_command_received (false),
+    zap_connected (false),
+    zap_request_sent (false),
+    zap_reply_received (false)
 {
+    const int rc = session->zap_connect ();
+    if (rc == 0)
+        zap_connected = true;
 }
 
 zmq::null_mechanism_t::~null_mechanism_t ()
@@ -47,6 +59,18 @@ int zmq::null_mechanism_t::next_handshake_message (msg_t *msg_)
         errno = EAGAIN;
         return -1;
     }
+    if (zap_connected && !zap_reply_received) {
+        if (zap_request_sent) {
+            errno = EAGAIN;
+            return -1;
+        }
+        send_zap_request ();
+        zap_request_sent = true;
+        const int rc = receive_and_process_zap_reply ();
+        if (rc != 0)
+            return -1;
+        zap_reply_received = true;
+    }
 
     unsigned char * const command_buffer = (unsigned char *) malloc (512);
     alloc_assert (command_buffer);
@@ -112,7 +136,132 @@ int zmq::null_mechanism_t::process_handshake_message (msg_t *msg_)
     return rc;
 }
 
+int zmq::null_mechanism_t::zap_msg_available ()
+{
+    if (zap_reply_received) {
+        errno = EFSM;
+        return -1;
+    }
+    const int rc = receive_and_process_zap_reply ();
+    if (rc == 0)
+        zap_reply_received = true;
+    return rc;
+}
+
 bool zmq::null_mechanism_t::is_handshake_complete () const
 {
     return ready_command_received && ready_command_sent;
 }
+
+void zmq::null_mechanism_t::send_zap_request ()
+{
+    int rc;
+    msg_t msg;
+
+    //  Address delimiter frame
+    rc = msg.init ();
+    errno_assert (rc == 0);
+    msg.set_flags (msg_t::more);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+
+    //  Version frame
+    rc = msg.init_size (3);
+    errno_assert (rc == 0);
+    memcpy (msg.data (), "1.0", 3);
+    msg.set_flags (msg_t::more);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+
+    //  Request id frame
+    rc = msg.init_size (1);
+    errno_assert (rc == 0);
+    memcpy (msg.data (), "1", 1);
+    msg.set_flags (msg_t::more);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+
+    //  Domain frame
+    rc = msg.init ();
+    errno_assert (rc == 0);
+    msg.set_flags (msg_t::more);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+
+    //  Address frame
+    rc = msg.init_size (peer_address.length ());
+    errno_assert (rc == 0);
+    memcpy (msg.data (), peer_address.c_str (), peer_address.length ());
+    msg.set_flags (msg_t::more);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+
+    //  Mechanism frame
+    rc = msg.init_size (5);
+    errno_assert (rc == 0);
+    memcpy (msg.data (), "NULL", 5);
+    rc = session->write_zap_msg (&msg);
+    errno_assert (rc == 0);
+}
+
+int zmq::null_mechanism_t::receive_and_process_zap_reply ()
+{
+    int rc = 0;
+    msg_t msg [7];  //  ZAP reply consists of 7 frames
+
+    //  Initialize all reply frames
+    for (int i = 0; i < 7; i++) {
+        rc = msg [i].init ();
+        errno_assert (rc == 0);
+    }
+
+    for (int i = 0; i < 7; i++) {
+        rc = session->read_zap_msg (&msg [i]);
+        if (rc == -1)
+            break;
+        if ((msg [i].flags () & msg_t::more) == (i < 6? 0: msg_t::more)) {
+            errno = EPROTO;
+            rc = -1;
+            break;
+        }
+    }
+
+    if (rc != 0)
+        goto error;
+
+    //  Address delimiter frame
+    if (msg [0].size () > 0) {
+        errno = EPROTO;
+        goto error;
+    }
+
+    //  Version frame
+    if (msg [1].size () != 3 || memcmp (msg [1].data (), "1.0", 3)) {
+        errno = EPROTO;
+        goto error;
+    }
+
+    //  Request id frame
+    if (msg [2].size () != 1 || memcmp (msg [2].data (), "1", 1)) {
+        errno = EPROTO;
+        goto error;
+    }
+
+    //  Status code frame
+    if (msg [3].size () != 3 || memcmp (msg [3].data (), "200", 3)) {
+        errno = EACCES;
+        goto error;
+    }
+
+    //  Process metadata frame
+    rc = parse_metadata (static_cast <const unsigned char*> (msg [6].data ()),
+                         msg [6].size ());
+
+error:
+    for (int i = 0; i < 7; i++) {
+        const int rc2 = msg [i].close ();
+        errno_assert (rc2 == 0);
+    }
+
+    return rc;
+}
diff --git a/src/null_mechanism.hpp b/src/null_mechanism.hpp
index 2c5d9c27..cf98d172 100644
--- a/src/null_mechanism.hpp
+++ b/src/null_mechanism.hpp
@@ -27,23 +27,37 @@ namespace zmq
 {
 
     class msg_t;
+    class session_base_t;
 
     class null_mechanism_t : public mechanism_t
     {
     public:
 
-        null_mechanism_t (const options_t &options_);
+        null_mechanism_t (session_base_t *session_,
+                          const std::string &peer_address,
+                          const options_t &options_);
         virtual ~null_mechanism_t ();
 
         // mechanism implementation
         virtual int next_handshake_message (msg_t *msg_);
         virtual int process_handshake_message (msg_t *msg_);
+        virtual int zap_msg_available ();
         virtual bool is_handshake_complete () const;
 
     private:
 
+        session_base_t * const session;
+
+        const std::string peer_address;
+
         bool ready_command_sent;
         bool ready_command_received;
+        bool zap_connected;
+        bool zap_request_sent;
+        bool zap_reply_received;
+
+        void send_zap_request ();
+        int receive_and_process_zap_reply ();
     };
 
 }
diff --git a/src/stream_engine.cpp b/src/stream_engine.cpp
index 5392262e..5900b8e7 100644
--- a/src/stream_engine.cpp
+++ b/src/stream_engine.cpp
@@ -525,7 +525,8 @@ bool zmq::stream_engine_t::handshake ()
         alloc_assert (decoder);
 
         if (memcmp (greeting_recv + 12, "NULL\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 20) == 0) {
-            mechanism = new (std::nothrow) null_mechanism_t (options);
+            mechanism = new (std::nothrow)
+                null_mechanism_t (session, peer_address, options);
             alloc_assert (mechanism);
         }
         else