diff --git a/src/AsyncTCP.cpp b/src/AsyncTCP.cpp
index ce7c4f2..ba1929b 100644
--- a/src/AsyncTCP.cpp
+++ b/src/AsyncTCP.cpp
@@ -364,6 +364,7 @@ AsyncClient::AsyncClient(tcp_pcb* pcb)
 , _connect_port(0)
 , prev(NULL)
 , next(NULL)
+, _in_lwip_thread(false)
 {
     _pcb = pcb;
     if(_pcb){
@@ -403,7 +404,11 @@ bool AsyncClient::connect(IPAddress ip, uint16_t port){
 
     tcp_arg(pcb, this);
     tcp_err(pcb, &_tcp_error);
-    _tcp_connect(pcb, &addr, port,(tcp_connected_fn)&_s_connected);
+    if(_in_lwip_thread){
+        tcp_connect(pcb, &addr, port,(tcp_connected_fn)&_s_connected);
+    } else {
+        _tcp_connect(pcb, &addr, port,(tcp_connected_fn)&_s_connected);
+    }
     return true;
 }
 
@@ -432,8 +437,10 @@ int8_t AsyncClient::_connected(void* pcb, int8_t err){
         tcp_sent(_pcb, &_tcp_sent);
         tcp_poll(_pcb, &_tcp_poll, 1);
     }
+    _in_lwip_thread = true;
     if(_connect_cb)
         _connect_cb(_connect_cb_arg, this);
+    _in_lwip_thread = false;
     return ERR_OK;
 }
 
@@ -446,7 +453,11 @@ int8_t AsyncClient::_close(){
         tcp_recv(_pcb, NULL);
         tcp_err(_pcb, NULL);
         tcp_poll(_pcb, NULL, 0);
-        err = _tcp_close(_pcb);
+        if(_in_lwip_thread){
+            err = tcp_close(_pcb);
+        } else {
+            err = _tcp_close(_pcb);
+        }
         if(err != ERR_OK) {
             err = abort();
         }
@@ -536,14 +547,17 @@ int8_t AsyncClient::_poll(tcp_pcb* pcb){
 }
 
 void AsyncClient::_dns_found(ip_addr_t *ipaddr){
+    _in_lwip_thread = true;
     if(ipaddr){
         connect(IPAddress(ipaddr->u_addr.ip4.addr), _connect_port);
     } else {
+        log_e("dns fail");
         if(_error_cb)
             _error_cb(_error_cb_arg, this, -55);
         if(_discard_cb)
             _discard_cb(_discard_cb_arg, this);
     }
+    _in_lwip_thread = false;
 }
 
 bool AsyncClient::operator==(const AsyncClient &other) {
@@ -566,14 +580,22 @@ bool AsyncClient::connect(const char* host, uint16_t port){
 int8_t AsyncClient::abort(){
     if(_pcb) {
         log_w("state %d", _pcb->state);
-        _tcp_abort(_pcb);
+        if(_in_lwip_thread){
+            tcp_abort(_pcb);
+        } else {
+            _tcp_abort(_pcb);
+        }
         _pcb = NULL;
     }
     return ERR_ABRT;
 }
 
 void AsyncClient::close(bool now){
-    _tcp_recved(_pcb, _rx_ack_len);
+    if(_in_lwip_thread){
+        tcp_recved(_pcb, _rx_ack_len);
+    } else {
+        _tcp_recved(_pcb, _rx_ack_len);
+    }
     if(now)
         _close();
     else
@@ -620,14 +642,25 @@ size_t AsyncClient::add(const char* data, size_t size, uint8_t apiflags) {
     if(!room)
         return 0;
     size_t will_send = (room < size) ? room : size;
-    int8_t err = _tcp_write(_pcb, data, will_send, apiflags);
+    int8_t err = ERR_OK;
+    if(_in_lwip_thread){
+        err = tcp_write(_pcb, data, will_send, apiflags);
+    } else {
+        err = _tcp_write(_pcb, data, will_send, apiflags);
+    }
     if(err != ERR_OK)
         return 0;
     return will_send;
 }
 
 bool AsyncClient::send(){
-    if(_tcp_output(_pcb) == ERR_OK){
+    int8_t err = ERR_OK;
+    if(_in_lwip_thread){
+        err = tcp_output(_pcb);
+    } else {
+        err = _tcp_output(_pcb);
+    }
+    if(err == ERR_OK){
         _pcb_busy = true;
         _pcb_sent_at = millis();
         return true;
@@ -638,8 +671,13 @@ bool AsyncClient::send(){
 size_t AsyncClient::ack(size_t len){
     if(len > _rx_ack_len)
         len = _rx_ack_len;
-    if(len)
-        _tcp_recved(_pcb, len);
+    if(len){
+        if(_in_lwip_thread){
+            tcp_recved(_pcb, len);
+        } else {
+            _tcp_recved(_pcb, len);
+        }
+    }
     _rx_ack_len -= len;
     return len;
 }
@@ -896,6 +934,7 @@ AsyncServer::AsyncServer(IPAddress addr, uint16_t port)
 : _port(port)
 , _addr(addr)
 , _noDelay(false)
+, _in_lwip_thread(false)
 , _pcb(0)
 , _connect_cb(0)
 , _connect_cb_arg(0)
@@ -905,6 +944,7 @@ AsyncServer::AsyncServer(uint16_t port)
 : _port(port)
 , _addr((uint32_t) IPADDR_ANY)
 , _noDelay(false)
+, _in_lwip_thread(false)
 , _pcb(0)
 , _connect_cb(0)
 , _connect_cb_arg(0)
@@ -935,12 +975,16 @@ int8_t AsyncServer::_accept(tcp_pcb* pcb, int8_t err){
 
         AsyncClient *c = new AsyncClient(pcb);
         if(c){
+            _in_lwip_thread = true;
+            c->_in_lwip_thread = true;
             _connect_cb(_connect_cb_arg, c);
+            c->_in_lwip_thread = false;
+            _in_lwip_thread = false;
             return ERR_OK;
         }
     }
-    if(_tcp_close(pcb) != ERR_OK){
-        _tcp_abort(pcb);
+    if(tcp_close(pcb) != ERR_OK){
+        tcp_abort(pcb);
     }
     log_e("FAIL");
     return ERR_OK;
@@ -985,9 +1029,13 @@ void AsyncServer::begin(){
 
 void AsyncServer::end(){
     if(_pcb){
-        _tcp_abort(_pcb);
         tcp_arg(_pcb, NULL);
         tcp_accept(_pcb, NULL);
+        if(_in_lwip_thread){
+            tcp_abort(_pcb);
+        } else {
+            _tcp_abort(_pcb);
+        }
         _pcb = NULL;
     }
 }
diff --git a/src/AsyncTCP.h b/src/AsyncTCP.h
index a50d244..1c24ac9 100644
--- a/src/AsyncTCP.h
+++ b/src/AsyncTCP.h
@@ -156,6 +156,8 @@ class AsyncClient {
     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);
+
+    bool _in_lwip_thread;
 };
 
 class AsyncServer {
@@ -163,6 +165,7 @@ class AsyncServer {
     uint16_t _port;
     IPAddress _addr;
     bool _noDelay;
+    bool _in_lwip_thread;
     tcp_pcb* _pcb;
     AcConnectHandler _connect_cb;
     void* _connect_cb_arg;