diff --git a/src/epcore.c b/src/epcore.c
index 3f56006..2669c51 100644
--- a/src/epcore.c
+++ b/src/epcore.c
@@ -85,7 +85,13 @@ void * epcore_new (int maxfd, int dispmode)
     time(&pcore->startup_time);
     pcore->quit = 0;
 
+#ifdef HAVE_EVENTFD
+    pcore->wakeupfd = -1;
+#else
+    pcore->informport = 0;
+    pcore->informfd = INVALID_SOCKET;
     pcore->wakeupfd = INVALID_SOCKET;
+#endif
     pcore->wakeupdev = NULL;
 
     /* initialize memory pool resource */
diff --git a/src/epdns.c b/src/epdns.c
index 8eb0263..41f1423 100644
--- a/src/epdns.c
+++ b/src/epdns.c
@@ -28,7 +28,7 @@ int hostn_to_dot_format (void * name, int len, void * pdst, int dstlen)
 {
     uint8  * hostn = (uint8 * )name;
     uint8  * dst = (uint8 *)pdst;
-    uint32   labellen = 0;
+    int      labellen = 0;
     int      i, j;
 
     if (!hostn) return -1;
@@ -219,19 +219,27 @@ int dns_nsrv_load (void * vmgmt, char * nsip, char * resolv_file)
 {
     DnsMgmt * mgmt = (DnsMgmt *)vmgmt;
     DnsHost * host = NULL;
+#ifdef UNIX
     FILE    * fp = NULL;
     char      buf[1024];
     char    * p = NULL;
     int       len = 0;
- 
+#endif
+#ifdef _WIN32
+    FIXED_INFO       fi;
+    ULONG            ulen = sizeof(fi);
+    IP_ADDR_STRING * paddr = NULL;
+#endif
+
     if (!mgmt) return -1;
- 
+
     if (nsip) {
         host = dns_host_new(NULL, nsip, 0);
         if (host)
             dns_nsrv_add(mgmt->nsrv, host);
     }
- 
+
+#ifdef UNIX
     if (!resolv_file)
         resolv_file = "/etc/resolv.conf";
  
@@ -256,6 +264,33 @@ int dns_nsrv_load (void * vmgmt, char * nsip, char * resolv_file)
     }
  
     fclose(fp);
+#endif
+
+#ifdef _WIN32
+    /* retrieves network parameters for the local computer */
+    if (GetNetworkParams(&fi, &ulen) != ERROR_SUCCESS) {
+        return -100;
+    }
+
+    if (fi.DomainName && strlen(fi.DomainName) > 0) {
+        host = dns_host_new(NULL, fi.DomainName, 0);
+        if (host) dns_nsrv_add(mgmt->nsrv, host);
+    }
+
+    if (fi.DnsServerList.IpAddress.String && strlen(fi.DnsServerList.IpAddress.String) > 0) {
+        host = dns_host_new(NULL, fi.DnsServerList.IpAddress.String, 0);
+        if (host) dns_nsrv_add(mgmt->nsrv, host);
+    }
+
+    paddr = fi.DnsServerList.Next;
+    while(paddr != NULL) {
+        if (paddr->IpAddress.String && strlen(paddr->IpAddress.String) > 0) {
+            host = dns_host_new(NULL, paddr->IpAddress.String, 0);
+            if (host) dns_nsrv_add(mgmt->nsrv, host);
+        }
+        paddr = paddr->Next;
+    }
+#endif
 
     /*if (dns_nsrv_num(mgmt->nsrv) <= 1) {
         host = dns_host_new(NULL, "8.8.8.8", 0);
@@ -1902,6 +1937,7 @@ int dns_recv (void * vmgmt, void * pobj)
  
         frm = frame_new(toread);
  
+        socklen = sizeof(sock);
         memset(&sock, 0, sizeof(sock));
         ret = recvfrom(iodev_fd(pdev), frameP(frm), toread, 0, 
                        (struct sockaddr *)&sock, (socklen_t *)&socklen);
diff --git a/src/epepoll.c b/src/epepoll.c
index 07fd4ba..7bb3e5a 100644
--- a/src/epepoll.c
+++ b/src/epepoll.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003-2020 Ke Hengzhong <kehengzhong@hotmail.com>
+ * Copyright (c) 2003-2021 Ke Hengzhong <kehengzhong@hotmail.com>
  * All rights reserved. See MIT LICENSE for redistribution.
  */
 
@@ -176,7 +176,7 @@ int epump_epoll_dispatch (void * veps, btime_t * delay)
     int        len;
     int        ret = 0;
     int        sockerr = 0;
-    struct sockaddr   sock;
+    ep_sockaddr_t sock;
 
     if (!epump) return -1;
 
diff --git a/src/epselect.c b/src/epselect.c
index eafdb6f..e13fba3 100644
--- a/src/epselect.c
+++ b/src/epselect.c
@@ -125,7 +125,7 @@ int epump_select_dispatch (void * veps, btime_t * delay)
     int        addrlen;
     rbtnode_t * rbt = NULL;
     struct timeval * waitout, timeout;
-    struct sockaddr  sock;
+    ep_sockaddr_t    sock;
 
     if (!epump) return -1;
 
@@ -183,6 +183,8 @@ int epump_select_dispatch (void * veps, btime_t * delay)
         if (pdev->rwflag & RWF_READ && FD_ISSET(pdev->fd, &rFds)) {
             nfds--;
             if (pdev->fdtype == FDT_LISTEN) {
+                epump_select_clearpoll(epump, pdev);
+
                 PushConnAcceptEvent(epump, pdev);
 
 #ifdef HAVE_EVENTFD
@@ -193,6 +195,8 @@ int epump_select_dispatch (void * veps, btime_t * delay)
                 epcore_wakeup_recv(pcore);
 
             } else {
+                epump_select_clearpoll(epump, pdev);
+
                 PushReadableEvent(epump, pdev);
             }
         }
diff --git a/src/eptcp.c b/src/eptcp.c
index ab8d7ab..e4f5417 100644
--- a/src/eptcp.c
+++ b/src/eptcp.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003-2020 Ke Hengzhong <kehengzhong@hotmail.com>
+ * Copyright (c) 2003-2021 Ke Hengzhong <kehengzhong@hotmail.com>
  * All rights reserved. See MIT LICENSE for redistribution.
  */
 
@@ -126,8 +126,8 @@ void * eptcp_accept (void * vpcore, void * vld, void * para, int * retval,
     iodev_t   * pdev = NULL;
     socklen_t   addrlen;
     SOCKET      clifd;
-    struct sockaddr cliaddr;
-    struct sockaddr sock;
+    ep_sockaddr_t  cliaddr;
+    ep_sockaddr_t  sock;
  
     if (retval) *retval = -1;
     if (!pcore || !listendev) return NULL;
diff --git a/src/epump.c b/src/epump.c
index e2108b8..801fa69 100644
--- a/src/epump.c
+++ b/src/epump.c
@@ -157,7 +157,10 @@ void epump_recycle (void * vepump)
     if (!epump) return;
  
     pcore = (epcore_t *)epump->epcore;
-    if (!pcore) return epump_free(epump);
+    if (!pcore) {
+        epump_free(epump);
+        return;
+    }
 
     epump->quit = 1;
     epump->threadid = 0;
diff --git a/src/epwakeup.c b/src/epwakeup.c
index ddcdfc0..b176659 100644
--- a/src/epwakeup.c
+++ b/src/epwakeup.c
@@ -242,7 +242,7 @@ int epcore_wakeup_init (void * vpcore)
     do {
 
         pcore->informport += 1;
-        pcore->wakeupfd = udp_listen(localip, pcore->informport);
+        pcore->wakeupfd = udp_listen(localip, pcore->informport, NULL);
 
     } while (pcore->wakeupfd == INVALID_SOCKET && times++ < 20000);
 
@@ -350,6 +350,8 @@ int epcore_wakeup_getmon (void * vpcore, void * veps)
     if (!pcore) return -1;
     if (!epump) return -2;
  
+    epump_iodev_add(epump, pcore->wakeupdev);
+
     ev.data.ptr = pcore->wakeupdev;
     ev.events = EPOLLIN;
     if (epoll_ctl(epump->epoll_fd, EPOLL_CTL_ADD, pcore->wakeupfd, &ev) < 0) {
@@ -363,6 +365,8 @@ int epcore_wakeup_getmon (void * vpcore, void * veps)
     if (!pcore) return -1;
     if (!epump) return -2;
  
+    epump_iodev_add(epump, pcore->wakeupdev);
+
     if (!FD_ISSET(pcore->wakeupfd, &epump->readFds)) {
         FD_SET(pcore->wakeupfd, &epump->readFds);
     }
diff --git a/src/iodev.c b/src/iodev.c
index 7359515..7cde212 100644
--- a/src/iodev.c
+++ b/src/iodev.c
@@ -341,14 +341,65 @@ int iodev_rwflag_set(void * vpdev, uint8 rwflag)
 }
 
 
-int iodev_add_notify (void * vdev, uint8 rwflag)
+int iodev_set_poll (void * vdev)
 {
     iodev_t  * pdev = (iodev_t *)vdev;
     epcore_t * pcore = NULL;
     epump_t  * epump = NULL;
+
+    if (!pdev) return -1;
+
+    if (pdev->fd == INVALID_SOCKET) {
+        iodev_close(pdev);
+        return -2;
+    }
+
+    if (pdev->bindtype == BIND_ALL_EPUMP) { //3
+        pcore = (epcore_t *)pdev->epcore;
+        if (pcore)
+            return epump_thread_setpoll(pcore, pdev);
+    } else {
+        epump = (epump_t *)pdev->epump;
+        if (epump)
+            return (*epump->setpoll)(epump, pdev);
+    }
+
+    return -100;
+}
+
+int iodev_clear_poll (void * vdev)
+{
+    iodev_t  * pdev = (iodev_t *)vdev;
+    epcore_t * pcore = NULL;
+    epump_t  * epump = NULL;
+
+    if (!pdev) return -1;
+
+    if (pdev->fd == INVALID_SOCKET) {
+        iodev_close(pdev);
+        return -2;
+    }
+
+    if (pdev->bindtype == BIND_ALL_EPUMP) { //3
+        pcore = (epcore_t *)pdev->epcore;
+        if (pcore)
+            return epump_thread_delpoll(pcore, pdev);
+    } else {
+        epump = (epump_t *)pdev->epump;
+        if (epump)
+            return (*epump->delpoll)(epump, pdev);
+    }
+
+    return -100;
+}
+
+int iodev_add_notify (void * vdev, uint8 rwflag)
+{
+    iodev_t  * pdev = (iodev_t *)vdev;
     uint8      tmpflag = 0;
 
     if (!pdev) return -1;
+
     if (pdev->fd == INVALID_SOCKET) {
         iodev_close(pdev);
         return 0;
@@ -356,9 +407,6 @@ int iodev_add_notify (void * vdev, uint8 rwflag)
  
     if (rwflag == 0) return 0;
 
-    pcore = (epcore_t *)pdev->epcore;
-    if (!pcore) return -2;
- 
     EnterCriticalSection(&pdev->fdCS);
     tmpflag = pdev->rwflag | rwflag;
     if (pdev->rwflag != tmpflag) {
@@ -366,35 +414,24 @@ int iodev_add_notify (void * vdev, uint8 rwflag)
     }
     LeaveCriticalSection(&pdev->fdCS);
 
-    if (pdev->bindtype == BIND_ALL_EPUMP) { //3
-        epump_thread_setpoll(pcore, pdev);
-    } else {
-        epump = (epump_t *)pdev->epump;
-        if (epump) (*epump->setpoll)(epump, pdev);
-    }
- 
-    return 0;
+    return iodev_set_poll(pdev);
 }
 
 int iodev_del_notify (void * vdev, uint8 rwflag)
 {
     iodev_t  * pdev = (iodev_t *)vdev;
-    epcore_t * pcore = NULL;
-    epump_t  * epump = NULL;
     uint8      tmpflag = 0;
     int        setpoll = 0;
  
     if (!pdev) return -1;
+
     if (pdev->fd == INVALID_SOCKET) {
         iodev_close(pdev);
         return 0;
     }
  
     if (rwflag == 0) return 0;
- 
-    pcore = (epcore_t *)pdev->epcore;
-    if (!pcore) return -2;
- 
+
     EnterCriticalSection(&pdev->fdCS);
     tmpflag = pdev->rwflag & ~rwflag;
     if (pdev->rwflag != tmpflag) {
@@ -405,14 +442,7 @@ int iodev_del_notify (void * vdev, uint8 rwflag)
 
     if (!setpoll) return 0;
 
-    if (pdev->bindtype == BIND_ALL_EPUMP) { //3
-        epump_thread_setpoll(pcore, pdev);
-    } else {
-        epump = (epump_t *)pdev->epump;
-        if (epump) (*epump->setpoll)(epump, pdev);
-    }
- 
-    return 0;
+    return iodev_set_poll(pdev);
 }
 
 
diff --git a/src/ioevent.c b/src/ioevent.c
index 5ab2923..c14a009 100644
--- a/src/ioevent.c
+++ b/src/ioevent.c
@@ -162,7 +162,7 @@ int ioevent_push (void * vepump, int event, void * obj, void * cb, void * cbpara
     EnterCriticalSection(&epump->epcore->eventnumCS);
     epump->epcore->acc_event_num++;
     LeaveCriticalSection(&epump->epcore->eventnumCS);
- 
+
     if (arr_num(epump->epcore->worker_list) <= 0)
         return epump_ioevent_push(epump, ioe);
 
@@ -242,6 +242,10 @@ void * ioevent_execute (void * vpcore, void * vioe)
     iotimer_t  * piot = NULL;
     GeneralCB  * gcb = NULL;
     IOHandler  * iocb = NULL;
+#if defined (HAVE_SELECT)
+    iodev_t    * ptmp = NULL;
+    ulong        curid = 0;
+#endif
 
     DnsMsg     * dnsmsg = NULL;
 
@@ -281,11 +285,30 @@ void * ioevent_execute (void * vpcore, void * vioe)
             ioe->type == IOE_ACCEPT)
             pdev->iostate = IOS_READWRITE;
 
+#if defined (HAVE_SELECT)
+        curid = pdev->id;
+#endif
+
         if (pdev->callback)
             (*pdev->callback)(pdev->cbpara, pdev, ioe->type, pdev->fdtype);
         else if (pcore->callback)
             (*pcore->callback)(pcore->cbpara, pdev, ioe->type, pdev->fdtype);
  
+#if defined (HAVE_SELECT)
+        /* pdev may be closed during the execution of callback */
+
+        ptmp = epcore_iodev_find(pcore, curid);
+
+        if (ioe->type == IOE_INVALID_DEV && ptmp) {
+            iodev_close(ptmp);
+            ptmp = NULL;
+
+        } else if (ptmp && ptmp->fd != INVALID_SOCKET) {
+            /* if underlying fd watching is epoll and ONESHOT mode,
+               READ notify should be added each time after callback */
+            iodev_set_poll(ptmp);
+        }
+#endif
         break;
  
     case IOE_TIMEOUT: