diff --git a/src/AsyncTCP.cpp b/src/AsyncTCP.cpp
index 174e8ac..f06cccc 100644
--- a/src/AsyncTCP.cpp
+++ b/src/AsyncTCP.cpp
@@ -256,7 +256,7 @@ static void _tcp_error(void * arg, int8_t err) {
 #include "lwip/priv/tcpip_priv.h"
 
 typedef struct {
-    struct tcpip_api_call call;
+    struct tcpip_api_call_data call;
     tcp_pcb * pcb;
     int8_t err;
     union {
@@ -279,20 +279,24 @@ typedef struct {
     };
 } tcp_api_call_t;
 
-static err_t _tcp_output_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_output_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
-    msg->err = tcp_output(msg->pcb);
+    if(msg->pcb){
+      msg->err = tcp_output(msg->pcb);
+    } else {
+      msg->err = 0;
+    }
     return msg->err;
 }
 
 static esp_err_t _tcp_output(tcp_pcb * pcb) {
     tcp_api_call_t msg;
     msg.pcb = pcb;
-    tcpip_api_call(_tcp_output_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_output_api, (struct tcpip_api_call_data*)&msg);
     return msg.err;
 }
 
-static err_t _tcp_write_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_write_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
     msg->err = tcp_write(msg->pcb, msg->write.data, msg->write.size, msg->write.apiflags);
     return msg->err;
@@ -304,11 +308,11 @@ static esp_err_t _tcp_write(tcp_pcb * pcb, const char* data, size_t size, uint8_
     msg.write.data = data;
     msg.write.size = size;
     msg.write.apiflags = apiflags;
-    tcpip_api_call(_tcp_write_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_write_api, (struct tcpip_api_call_data*)&msg);
     return msg.err;
 }
 
-static err_t _tcp_recved_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_recved_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
     msg->err = 0;
     tcp_recved(msg->pcb, msg->received);
@@ -319,11 +323,11 @@ static esp_err_t _tcp_recved(tcp_pcb * pcb, size_t len) {
     tcp_api_call_t msg;
     msg.pcb = pcb;
     msg.received = len;
-    tcpip_api_call(_tcp_recved_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_recved_api, (struct tcpip_api_call_data*)&msg);
     return msg.err;
 }
 
-static err_t _tcp_connect_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_connect_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
     msg->err = tcp_connect(msg->pcb, msg->connect.addr, msg->connect.port, msg->connect.cb);
     return msg->err;
@@ -335,11 +339,11 @@ static esp_err_t _tcp_connect(tcp_pcb * pcb, ip_addr_t * addr, uint16_t port, tc
     msg.connect.addr = addr;
     msg.connect.port = port;
     msg.connect.cb = cb;
-    tcpip_api_call(_tcp_connect_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_connect_api, (struct tcpip_api_call_data*)&msg);
     return msg.err;
 }
 
-static err_t _tcp_close_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_close_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
     msg->err = tcp_close(msg->pcb);
     return msg->err;
@@ -349,11 +353,11 @@ static esp_err_t _tcp_close(tcp_pcb * pcb) {
     tcp_api_call_t msg;
     msg.pcb = pcb;
     //ets_printf("close 0x%08x\n", (uint32_t)pcb);
-    tcpip_api_call(_tcp_close_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_close_api, (struct tcpip_api_call_data*)&msg);
     return msg.err;
 }
 
-static err_t _tcp_abort_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_abort_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
     msg->err = 0;
     tcp_abort(msg->pcb);
@@ -364,11 +368,11 @@ static esp_err_t _tcp_abort(tcp_pcb * pcb) {
     tcp_api_call_t msg;
     msg.pcb = pcb;
     //ets_printf("abort 0x%08x\n", (uint32_t)pcb);
-    tcpip_api_call(_tcp_abort_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_abort_api, (struct tcpip_api_call_data*)&msg);
     return msg.err;
 }
 
-static err_t _tcp_bind_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_bind_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
     msg->err = tcp_bind(msg->pcb, msg->bind.addr, msg->bind.port);
     return msg->err;
@@ -379,11 +383,11 @@ static esp_err_t _tcp_bind(tcp_pcb * pcb, ip_addr_t * addr, uint16_t port) {
     msg.pcb = pcb;
     msg.bind.addr = addr;
     msg.bind.port = port;
-    tcpip_api_call(_tcp_bind_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_bind_api, (struct tcpip_api_call_data*)&msg);
     return msg.err;
 }
 
-static err_t _tcp_listen_api(struct tcpip_api_call *api_call_msg){
+static err_t _tcp_listen_api(struct tcpip_api_call_data *api_call_msg){
     tcp_api_call_t * msg = (tcp_api_call_t *)api_call_msg;
     msg->err = 0;
     msg->pcb = tcp_listen_with_backlog(msg->pcb, msg->backlog);
@@ -394,7 +398,7 @@ static tcp_pcb * _tcp_listen_with_backlog(tcp_pcb * pcb, uint8_t backlog) {
     tcp_api_call_t msg;
     msg.pcb = pcb;
     msg.backlog = backlog?backlog:0xFF;
-    tcpip_api_call(_tcp_listen_api, (struct tcpip_api_call*)&msg);
+    tcpip_api_call(_tcp_listen_api, (struct tcpip_api_call_data*)&msg);
     return msg.pcb;
 }
 #define _tcp_listen(p) _tcp_listen_with_backlog(p, 0xFF);
@@ -432,6 +436,8 @@ AsyncClient::AsyncClient(tcp_pcb* pcb)
 , next(NULL)
 , _in_lwip_thread(false)
 {
+    //ets_printf("+: 0x%08x\n", (uint32_t)this);
+
     _pcb = pcb;
     if(_pcb){
         _rx_last_packet = millis();
@@ -447,6 +453,8 @@ AsyncClient::AsyncClient(tcp_pcb* pcb)
 AsyncClient::~AsyncClient(){
     if(_pcb)
         _close();
+
+    //ets_printf("-: 0x%08x\n", (uint32_t)this);
 }
 
 bool AsyncClient::connect(IPAddress ip, uint16_t port){
@@ -512,6 +520,7 @@ int8_t AsyncClient::_connected(void* pcb, int8_t err){
 }
 
 int8_t AsyncClient::_close(){
+    //ets_printf("X: 0x%08x\n", (uint32_t)this);
     int8_t err = ERR_OK;
     if(_pcb) {
         //log_i("");
@@ -520,6 +529,7 @@ int8_t AsyncClient::_close(){
         tcp_recv(_pcb, NULL);
         tcp_err(_pcb, NULL);
         tcp_poll(_pcb, NULL, 0);
+        _tcp_clear_events(this);
         if(_in_lwip_thread){
             err = tcp_close(_pcb);
         } else {
@@ -529,7 +539,6 @@ int8_t AsyncClient::_close(){
             err = abort();
         }
         _pcb = NULL;
-        _tcp_clear_events(this);
         if(_discard_cb)
             _discard_cb(_discard_cb_arg, this);
     }
@@ -562,6 +571,13 @@ int8_t AsyncClient::_sent(tcp_pcb* pcb, uint16_t len) {
 }
 
 int8_t AsyncClient::_recv(tcp_pcb* pcb, pbuf* pb, int8_t err) {
+    if(!_pcb || pcb != _pcb){
+        log_e("0x%08x != 0x%08x", (uint32_t)pcb, (uint32_t)_pcb);
+        if(pb){
+            pbuf_free(pb);
+        }
+        return ERR_OK;
+    }
     _in_lwip_thread = false;
     if(pb == NULL){
         return _close();
@@ -621,7 +637,7 @@ int8_t AsyncClient::_poll(tcp_pcb* pcb){
     return ERR_OK;
 }
 
-void AsyncClient::_dns_found(ip_addr_t *ipaddr){
+void AsyncClient::_dns_found(struct ip_addr *ipaddr){
     _in_lwip_thread = true;
     if(ipaddr){
         connect(IPAddress(ipaddr->u_addr.ip4.addr), _connect_port);
@@ -943,31 +959,58 @@ void AsyncClient::onPoll(AcConnectHandler cb, void* arg){
 }
 
 
-void AsyncClient::_s_dns_found(const char * name, ip_addr_t * ipaddr, void * arg){
-    reinterpret_cast<AsyncClient*>(arg)->_dns_found(ipaddr);
+void AsyncClient::_s_dns_found(const char * name, struct ip_addr * ipaddr, void * arg){
+    if(arg){
+        reinterpret_cast<AsyncClient*>(arg)->_dns_found(ipaddr);
+    } else {
+        log_e("Bad Arg: 0x%08x", arg);
+    }
 }
 
 int8_t AsyncClient::_s_poll(void * arg, struct tcp_pcb * pcb) {
-    reinterpret_cast<AsyncClient*>(arg)->_poll(pcb);
+    if(arg && pcb){
+        reinterpret_cast<AsyncClient*>(arg)->_poll(pcb);
+    } else {
+        log_e("Bad Args: 0x%08x 0x%08x", arg, pcb);
+    }
     return ERR_OK;
 }
 
 int8_t AsyncClient::_s_recv(void * arg, struct tcp_pcb * pcb, struct pbuf *pb, int8_t err) {
-    reinterpret_cast<AsyncClient*>(arg)->_recv(pcb, pb, err);
+    if(arg && pcb){
+        reinterpret_cast<AsyncClient*>(arg)->_recv(pcb, pb, err);
+    } else {
+        if(pb){
+           pbuf_free(pb);
+        }
+        log_e("Bad Args: 0x%08x 0x%08x", arg, pcb);
+    }
     return ERR_OK;
 }
 
 int8_t AsyncClient::_s_sent(void * arg, struct tcp_pcb * pcb, uint16_t len) {
-    reinterpret_cast<AsyncClient*>(arg)->_sent(pcb, len);
+    if(arg && pcb){
+        reinterpret_cast<AsyncClient*>(arg)->_sent(pcb, len);
+    } else {
+        log_e("Bad Args: 0x%08x 0x%08x", arg, pcb);
+    }
     return ERR_OK;
 }
 
 void AsyncClient::_s_error(void * arg, int8_t err) {
-    reinterpret_cast<AsyncClient*>(arg)->_error(err);
+    if(arg){
+        reinterpret_cast<AsyncClient*>(arg)->_error(err);
+    } else {
+        log_e("Bad Arg: 0x%08x", arg);
+    }
 }
 
 int8_t AsyncClient::_s_connected(void * arg, void * pcb, int8_t err){
-    reinterpret_cast<AsyncClient*>(arg)->_connected(pcb, err);
+    if(arg && pcb){
+        reinterpret_cast<AsyncClient*>(arg)->_connected(pcb, err);
+    } else {
+        log_e("Bad Args: 0x%08x 0x%08x", arg, pcb);
+    }
     return ERR_OK;
 }
 
@@ -1122,9 +1165,9 @@ void AsyncServer::end(){
         tcp_arg(_pcb, NULL);
         tcp_accept(_pcb, NULL);
         if(_in_lwip_thread){
-            tcp_abort(_pcb);
+            tcp_close(_pcb);
         } else {
-            _tcp_abort(_pcb);
+            _tcp_close(_pcb);
         }
         _pcb = NULL;
     }
diff --git a/src/AsyncTCP.h b/src/AsyncTCP.h
index 79664bf..6cd0fca 100644
--- a/src/AsyncTCP.h
+++ b/src/AsyncTCP.h
@@ -43,7 +43,7 @@ typedef std::function<void(void*, AsyncClient*, struct pbuf *pb)> AcPacketHandle
 typedef std::function<void(void*, AsyncClient*, uint32_t time)> AcTimeoutHandler;
 
 struct tcp_pcb;
-struct _ip_addr;
+struct ip_addr;
 
 class AsyncClient {
   protected:
@@ -81,7 +81,7 @@ class AsyncClient {
     void _error(int8_t err);
     int8_t _poll(tcp_pcb* pcb);
     int8_t _sent(tcp_pcb* pcb, uint16_t len);
-    void _dns_found(struct _ip_addr *ipaddr);
+    void _dns_found(struct ip_addr *ipaddr);
 
 
   public:
@@ -108,13 +108,13 @@ class AsyncClient {
 
     bool canSend();//ack is not pending
     size_t space();
-    size_t add(const char* data, size_t size, uint8_t apiflags=0);//add for sending
+    size_t add(const char* data, size_t size, uint8_t apiflags=ASYNC_WRITE_FLAG_COPY);//add for sending
     bool send();//send all data added with the method above
     size_t ack(size_t len); //ack data that you have not acked using the method below
     void ackLater(){ _ack_pcb = false; } //will not ack the current packet. Call from onData
 
     size_t write(const char* data);
-    size_t write(const char* data, size_t size, uint8_t apiflags=0); //only when canSend() == true
+    size_t write(const char* data, size_t size, uint8_t apiflags=ASYNC_WRITE_FLAG_COPY); //only when canSend() == true
 
     uint8_t state();
     bool connecting();
@@ -161,7 +161,7 @@ class AsyncClient {
     static void _s_error(void *arg, int8_t err);
     static int8_t _s_sent(void *arg, struct tcp_pcb *tpcb, uint16_t len);
     static int8_t _s_connected(void* arg, void* tpcb, int8_t err);
-    static void _s_dns_found(const char *name, struct _ip_addr *ipaddr, void *arg);
+    static void _s_dns_found(const char *name, struct ip_addr *ipaddr, void *arg);
 
     bool _in_lwip_thread;
 };