diff --git a/trunk/src/app/srs_app_rtmp_conn.cpp b/trunk/src/app/srs_app_rtmp_conn.cpp
index 6e4c5d9ba..bd98b1801 100644
--- a/trunk/src/app/srs_app_rtmp_conn.cpp
+++ b/trunk/src/app/srs_app_rtmp_conn.cpp
@@ -410,7 +410,7 @@ int SrsRtmpConn::do_cycle()
     srs_info("discovery app success. schema=%s, vhost=%s, port=%s, app=%s",
         req->schema.c_str(), req->vhost.c_str(), req->port.c_str(), req->app.c_str());
     
-    if (req->schema.empty() || req->vhost.empty() || req->app.empty()) {
+    if (req->schema.empty() || req->vhost.empty() || req->port == 0 || req->app.empty()) {
         ret = ERROR_RTMP_REQ_TCURL;
         srs_error("discovery tcUrl failed. "
             "tcUrl=%s, schema=%s, vhost=%s, port=%d, app=%s, ret=%d",
diff --git a/trunk/src/app/srs_app_server.cpp b/trunk/src/app/srs_app_server.cpp
old mode 100755
new mode 100644
index e049ad500..93897b545
--- a/trunk/src/app/srs_app_server.cpp
+++ b/trunk/src/app/srs_app_server.cpp
@@ -968,11 +968,11 @@ int SrsServer::do_cycle()
     
     // the deamon thread, update the time cache
     while (true) {
-        if(handler && (ret = handler->on_cycle((int)conns.size())) != ERROR_SUCCESS){
+        if (handler && (ret = handler->on_cycle()) != ERROR_SUCCESS) {
             srs_error("cycle handle failed. ret=%d", ret);
             return ret;
         }
-            
+
         // the interval in config.
         int heartbeat_max_resolution = (int)(_srs_config->get_heartbeat_interval() / SRS_SYS_CYCLE_INTERVAL);
         
@@ -1254,15 +1254,20 @@ int SrsServer::accept_client(SrsListenerType type, st_netfd_t client_stfd)
     int ret = ERROR_SUCCESS;
     
     int fd = st_netfd_fileno(client_stfd);
-    
+
+    // check connection limitation.
     int max_connections = _srs_config->get_max_connections();
+    if (handler && (ret = handler->on_accept_client(max_connections, (int)conns.size()) != ERROR_SUCCESS)) {
+        srs_error("handle accept client failed, drop client: "
+            "clients=%d, max=%d, fd=%d. ret=%d", (int)conns.size(), max_connections, fd, ret);
+        srs_close_stfd(client_stfd);
+        return ERROR_SUCCESS;
+    }
     if ((int)conns.size() >= max_connections) {
         srs_error("exceed the max connections, drop client: "
             "clients=%d, max=%d, fd=%d", (int)conns.size(), max_connections, fd);
-            
         srs_close_stfd(client_stfd);
-        
-        return ret;
+        return ERROR_SUCCESS;
     }
     
     // avoid fd leak when fork.
diff --git a/trunk/src/app/srs_app_server.hpp b/trunk/src/app/srs_app_server.hpp
index bd1b4bc2c..23f9dead8 100644
--- a/trunk/src/app/srs_app_server.hpp
+++ b/trunk/src/app/srs_app_server.hpp
@@ -225,7 +225,11 @@ public:
     /**
     * do on_cycle while server doing cycle.
     */
-    virtual int on_cycle(int connections) = 0;
+    virtual int on_cycle() = 0;
+    /**
+     * callback the handler when got client.
+     */
+    virtual int on_accept_client(int conf_conns, int curr_conns) = 0;
 };
 
 /**
diff --git a/trunk/src/app/srs_app_st.cpp b/trunk/src/app/srs_app_st.cpp
index e7fecf3ad..18f45d80b 100644
--- a/trunk/src/app/srs_app_st.cpp
+++ b/trunk/src/app/srs_app_st.cpp
@@ -440,7 +440,7 @@ int SrsTcpClient::connect(string host, int port, int64_t timeout)
     
     // connect host.
     if ((ret = srs_socket_connect(host, port, timeout, &stfd)) != ERROR_SUCCESS) {
-        srs_error("mpegts: connect server %s:%d failed. ret=%d", host.c_str(), port, ret);
+        srs_error("connect server %s:%d failed. ret=%d", host.c_str(), port, ret);
         return ret;
     }
     
diff --git a/trunk/src/kernel/srs_kernel_utility.cpp b/trunk/src/kernel/srs_kernel_utility.cpp
index e1a71898d..8660b9c17 100644
--- a/trunk/src/kernel/srs_kernel_utility.cpp
+++ b/trunk/src/kernel/srs_kernel_utility.cpp
@@ -356,7 +356,9 @@ vector<string> srs_string_split(string str, string flag)
     string s = str;
     
     while ((pos = s.find(flag)) != string::npos) {
-        arr.push_back(s.substr(0, pos));
+        if (pos != 0) {
+            arr.push_back(s.substr(0, pos));
+        }
         s = s.substr(pos + flag.length());
     }
     
@@ -406,7 +408,9 @@ vector<string> srs_string_split(string str, vector<string> flags)
             break;
         }
         
-        arr.push_back(s.substr(0, pos));
+        if (pos != 0) {
+            arr.push_back(s.substr(0, pos));
+        }
         s = s.substr(pos + flag.length());
     }
     
diff --git a/trunk/src/kernel/srs_kernel_utility.hpp b/trunk/src/kernel/srs_kernel_utility.hpp
index f604bf7ad..1b097ae3e 100644
--- a/trunk/src/kernel/srs_kernel_utility.hpp
+++ b/trunk/src/kernel/srs_kernel_utility.hpp
@@ -88,6 +88,8 @@ extern bool srs_string_starts_with(std::string str, std::string flag0, std::stri
 extern bool srs_string_starts_with(std::string str, std::string flag0, std::string flag1, std::string flag2, std::string flag3);
 // whether string contains with
 extern bool srs_string_contains(std::string str, std::string flag);
+// find the min match in str for flags.
+extern std::string srs_string_min_match(std::string str, std::vector<std::string> flags);
 // split the string by flag to array.
 extern std::vector<std::string> srs_string_split(std::string str, std::string flag);
 extern std::vector<std::string> srs_string_split(std::string str, std::vector<std::string> flags);
@@ -97,9 +99,9 @@ extern int srs_create_dir_recursively(std::string dir);
 
 // whether path exists.
 extern bool srs_path_exists(std::string path);
-// get the dirname of path, for instance, filename("/live/livestream")="/live"
+// get the dirname of path, for instance, dirname("/live/livestream")="/live"
 extern std::string srs_path_dirname(std::string path);
-// get the basename of path, for instance, filename("/live/livestream")="livestream"
+// get the basename of path, for instance, basename("/live/livestream")="livestream"
 extern std::string srs_path_basename(std::string path);
 // get the filename of path, for instance, filename("livestream.flv")="livestream"
 extern std::string srs_path_filename(std::string path);