diff --git a/src/core/base.c b/src/core/base.c
index 4f0c0805bcf..0b0577bf9d2 100644
--- a/src/core/base.c
+++ b/src/core/base.c
@@ -96,22 +96,17 @@ void swoole_init(void)
     swMutex_create(&SwooleGS->lock_2, 1);
     swMutex_create(&SwooleG.lock, 0);
 
-#ifdef _WIN32
     SwooleG.max_sockets = 1024;
-#else
+#ifndef _WIN32
     struct rlimit rlmt;
     if (getrlimit(RLIMIT_NOFILE, &rlmt) < 0)
     {
         swWarn("getrlimit() failed. Error: %s[%d]", strerror(errno), errno);
-        SwooleG.max_sockets = 1024;
     }
     else
     {
-        SwooleG.max_sockets = (uint32_t) rlmt.rlim_cur;
-        if (SwooleG.max_sockets > SW_MAX_CONNECTION)
-        {
-            SwooleG.max_sockets = SW_MAX_CONNECTION;
-        }
+        SwooleG.max_sockets = MAX((uint32_t) rlmt.rlim_cur, 1024);
+        SwooleG.max_sockets = MIN((uint32_t) rlmt.rlim_cur, SW_SESSION_LIST_SIZE);
     }
 #endif
 
diff --git a/src/network/server.c b/src/network/server.c
index 658b4511d6a..995a1ec3f5e 100644
--- a/src/network/server.c
+++ b/src/network/server.c
@@ -267,21 +267,24 @@ static int swServer_start_check(swServer *serv)
     {
         serv->reactor_num = serv->worker_num;
     }
-    if (SwooleG.max_sockets > 0 && serv->max_connection > SwooleG.max_sockets)
+    // max connections
+    uint32_t minimum_connection = (serv->worker_num + serv->task_worker_num) * 2 + 32;
+    if (serv->max_connection < minimum_connection)
     {
-        swWarn("serv->max_connection is exceed the maximum value[%d].", SwooleG.max_sockets);
         serv->max_connection = SwooleG.max_sockets;
+        swWarn("serv->max_connection must be bigger than %u, it's reset to %u", minimum_connection, SwooleG.max_sockets);
     }
-    if (serv->max_connection < (serv->worker_num + serv->task_worker_num) * 2 + 32)
+    else if (SwooleG.max_sockets > 0 && serv->max_connection > SwooleG.max_sockets)
     {
-        swWarn("serv->max_connection is too small.");
         serv->max_connection = SwooleG.max_sockets;
+        swWarn("serv->max_connection is exceed the maximum value, it's reset to %u.", SwooleG.max_sockets);
     }
-    if (serv->max_connection > SW_SESSION_LIST_SIZE)
+    else if (serv->max_connection > SW_SESSION_LIST_SIZE)
     {
-        swWarn("serv->max_connection is exceed the SW_SESSION_LIST_SIZE[%d].", SW_SESSION_LIST_SIZE);
         serv->max_connection = SW_SESSION_LIST_SIZE;
+        swWarn("serv->max_connection is exceed the SW_SESSION_LIST_SIZE, it's reset to %u.", SW_SESSION_LIST_SIZE);
     }
+    // package max length
     swListenPort *ls;
     LL_FOREACH(serv->listen_list, ls)
     {
@@ -800,7 +803,7 @@ void swServer_init(swServer *serv)
     serv->dispatch_mode = SW_DISPATCH_FDMOD;
 
     serv->worker_num = SW_CPU_NUM;
-    serv->max_connection = SwooleG.max_sockets < SW_SESSION_LIST_SIZE ? SwooleG.max_sockets : SW_SESSION_LIST_SIZE;
+    serv->max_connection = MIN(SW_MAX_CONNECTION, SwooleG.max_sockets);
 
     serv->max_request = 0;
     serv->max_wait_time = SW_WORKER_MAX_WAIT_TIME;
diff --git a/src/network/thread_pool.c b/src/network/thread_pool.c
index adaa8795729..9f56e61bc64 100644
--- a/src/network/thread_pool.c
+++ b/src/network/thread_pool.c
@@ -42,7 +42,7 @@ int swThreadPool_create(swThreadPool *pool, int thread_num)
         return SW_ERR;
     }
 #else
-    int size = SwooleG.max_sockets >= SW_THREADPOOL_QUEUE_LEN ? SwooleG.max_sockets + 1 : SW_THREADPOOL_QUEUE_LEN;
+    int size = MAX(SwooleG.max_sockets + 1, SW_THREADPOOL_QUEUE_LEN);
     if (swRingQueue_init(&pool->queue, size) < 0)
     {
         return SW_ERR;
diff --git a/swoole_server.c b/swoole_server.c
index f2be7f9ecf0..4ad2b04c16e 100644
--- a/swoole_server.c
+++ b/swoole_server.c
@@ -2197,7 +2197,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "reactor_num", v))
     {
         convert_to_long(v);
-        serv->reactor_num = (int) Z_LVAL_P(v);
+        serv->reactor_num = (uint16_t) Z_LVAL_P(v);
         if (serv->reactor_num <= 0)
         {
             serv->reactor_num = SwooleG.cpu_num;
@@ -2207,7 +2207,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "worker_num", v))
     {
         convert_to_long(v);
-        serv->worker_num = (int) Z_LVAL_P(v);
+        serv->worker_num = (uint16_t) Z_LVAL_P(v);
         if (serv->worker_num <= 0)
         {
             serv->worker_num = SwooleG.cpu_num;
@@ -2228,7 +2228,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "max_coro_num", v) || php_swoole_array_get_value(vht, "max_coroutine", v))
     {
         convert_to_long(v);
-        COROG.max_coro_num = (int) Z_LVAL_P(v);
+        COROG.max_coro_num = (uint32_t) Z_LVAL_P(v);
         if (COROG.max_coro_num <= 0)
         {
             COROG.max_coro_num = SW_DEFAULT_MAX_CORO_NUM;
@@ -2253,7 +2253,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "dispatch_mode", v))
     {
         convert_to_long(v);
-        serv->dispatch_mode = (int) Z_LVAL_P(v);
+        serv->dispatch_mode = (uint8_t) Z_LVAL_P(v);
     }
     //dispatch function
     if (php_swoole_array_get_value(vht, "dispatch_func", v))
@@ -2300,7 +2300,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "log_level", v))
     {
         convert_to_long(v);
-        SwooleG.log_level = (int) Z_LVAL_P(v);
+        SwooleG.log_level = (uint8_t) Z_LVAL_P(v);
     }
     /**
      * for dispatch_mode = 1/3
@@ -2308,7 +2308,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "discard_timeout_request", v))
     {
         convert_to_boolean(v);
-        serv->discard_timeout_request = Z_BVAL_P(v);
+        serv->discard_timeout_request = (uint32_t) Z_BVAL_P(v);
     }
     //onConnect/onClose event
     if (php_swoole_array_get_value(vht, "enable_unsafe_event", v))
@@ -2332,7 +2332,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "task_worker_num", v))
     {
         convert_to_long(v);
-        serv->task_worker_num = (int) Z_LVAL_P(v);
+        serv->task_worker_num = (uint16_t) Z_LVAL_P(v);
         if (task_callbacks == NULL)
         {
             task_callbacks = swHashMap_new(1024, NULL);
@@ -2373,7 +2373,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "task_ipc_mode", v))
     {
         convert_to_long(v);
-        serv->task_ipc_mode = (int) Z_LVAL_P(v);
+        serv->task_ipc_mode = (uint8_t) Z_LVAL_P(v);
     }
     /**
      * Temporary file directory for task_worker
@@ -2397,25 +2397,25 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "task_max_request", v))
     {
         convert_to_long(v);
-        serv->task_max_request = (int) Z_LVAL_P(v);
+        serv->task_max_request = (uint16_t) Z_LVAL_P(v);
     }
     //max_connection
     if (php_swoole_array_get_value(vht, "max_connection", v) || php_swoole_array_get_value(vht, "max_conn", v))
     {
         convert_to_long(v);
-        serv->max_connection = (int) Z_LVAL_P(v);
+        serv->max_connection = (uint32_t) Z_LVAL_P(v);
     }
     //heartbeat_check_interval
     if (php_swoole_array_get_value(vht, "heartbeat_check_interval", v))
     {
         convert_to_long(v);
-        serv->heartbeat_check_interval = (int) Z_LVAL_P(v);
+        serv->heartbeat_check_interval = (uint16_t) Z_LVAL_P(v);
     }
     //heartbeat idle time
     if (php_swoole_array_get_value(vht, "heartbeat_idle_time", v))
     {
         convert_to_long(v);
-        serv->heartbeat_idle_time = (int) Z_LVAL_P(v);
+        serv->heartbeat_idle_time = (uint16_t) Z_LVAL_P(v);
 
         if (serv->heartbeat_check_interval > serv->heartbeat_idle_time)
         {
@@ -2431,7 +2431,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "max_request", v))
     {
         convert_to_long(v);
-        serv->max_request = (int) Z_LVAL_P(v);
+        serv->max_request = (uint32_t) Z_LVAL_P(v);
     }
     //reload async
     if (php_swoole_array_get_value(vht, "reload_async", v))
@@ -2555,7 +2555,7 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "buffer_input_size", v))
     {
         convert_to_long(v);
-        serv->buffer_input_size = (int) Z_LVAL_P(v);
+        serv->buffer_input_size = (uint32_t) Z_LVAL_P(v);
     }
     /**
      * buffer output size
@@ -2563,13 +2563,13 @@ PHP_METHOD(swoole_server, set)
     if (php_swoole_array_get_value(vht, "buffer_output_size", v))
     {
         convert_to_long(v);
-        serv->buffer_output_size = (int) Z_LVAL_P(v);
+        serv->buffer_output_size = (uint32_t) Z_LVAL_P(v);
     }
     //message queue key
     if (php_swoole_array_get_value(vht, "message_queue_key", v))
     {
         convert_to_long(v);
-        serv->message_queue_key = (int) Z_LVAL_P(v);
+        serv->message_queue_key = (uint64_t) Z_LVAL_P(v);
     }
 
     zval *retval = NULL;