diff --git a/src/Config.py b/src/Config.py
index 15a0c87f..a9e05a6f 100644
--- a/src/Config.py
+++ b/src/Config.py
@@ -285,6 +285,8 @@ class Config(object):
 
         self.parser.add_argument('--expose_no_ownership', help='By default, ZeroNet tries checking updates for own sites more frequently. This can be used by a third party for revealing the network addresses of a site owner. If this option is enabled, ZeroNet performs the checks in the same way for any sites.', type='bool', choices=[True, False], default=False)
 
+        self.parser.add_argument('--simultaneous_connection_throttle_threshold', help='Throttle opening new connections when the number of outgoing connections in not fully established state exceeds the threshold.', default=15, type=int, metavar='simultaneous_connection_throttle_threshold')
+
         self.parser.add_argument('--fileserver_ip', help='FileServer bind address', default="*", metavar='ip')
         self.parser.add_argument('--fileserver_port', help='FileServer bind port (0: randomize)', default=0, type=int, metavar='port')
         self.parser.add_argument('--fileserver_port_range', help='FileServer randomization range', default="10000-40000", metavar='port')
diff --git a/src/Connection/Connection.py b/src/Connection/Connection.py
index c147ee35..44665b2f 100644
--- a/src/Connection/Connection.py
+++ b/src/Connection/Connection.py
@@ -17,7 +17,7 @@ from util import helper
 class Connection(object):
     __slots__ = (
         "sock", "sock_wrapped", "ip", "port", "cert_pin", "target_onion", "id", "protocol", "type", "server", "unpacker", "unpacker_bytes", "req_id", "ip_type",
-        "handshake", "crypt", "connected", "event_connected", "closed", "start_time", "handshake_time", "last_recv_time", "is_private_ip", "is_tracker_connection",
+        "handshake", "crypt", "connected", "connecting", "event_connected", "closed", "start_time", "handshake_time", "last_recv_time", "is_private_ip", "is_tracker_connection",
         "last_message_time", "last_send_time", "last_sent_time", "incomplete_buff_recv", "bytes_recv", "bytes_sent", "cpu_time", "send_lock",
         "last_ping_delay", "last_req_time", "last_cmd_sent", "last_cmd_recv", "bad_actions", "sites", "name", "waiting_requests", "waiting_streams"
     )
@@ -50,6 +50,7 @@ class Connection(object):
         self.crypt = None  # Connection encryption method
         self.sock_wrapped = False  # Socket wrapped to encryption
 
+        self.connecting = False
         self.connected = False
         self.event_connected = gevent.event.AsyncResult()  # Solves on handshake received
         self.closed = False
@@ -118,6 +119,15 @@ class Connection(object):
 
     # Open connection to peer and wait for handshake
     def connect(self):
+        self.connecting = True
+        try:
+            return self._connect()
+        except Exception as err:
+            self.connecting = False
+            self.connected = False
+            raise
+
+    def _connect(self):
         self.updateOnlineStatus(outgoing_activity=True)
 
         if not self.event_connected or self.event_connected.ready():
@@ -236,6 +246,7 @@ class Connection(object):
         self.protocol = "v2"
         self.updateName()
         self.connected = True
+        self.connecting = False
         buff_len = 0
         req_len = 0
         self.unpacker_bytes = 0
@@ -634,6 +645,7 @@ class Connection(object):
             return False  # Already closed
         self.closed = True
         self.connected = False
+        self.connecting = False
         if self.event_connected:
             self.event_connected.set(False)
 
diff --git a/src/Connection/ConnectionServer.py b/src/Connection/ConnectionServer.py
index 9f24e377..9c16b774 100644
--- a/src/Connection/ConnectionServer.py
+++ b/src/Connection/ConnectionServer.py
@@ -298,6 +298,7 @@ class ConnectionServer(object):
                 raise Exception("This peer is blacklisted")
 
             try:
+                #self.log.info("Connection to: %s:%s", ip, port)
                 if has_per_site_onion:  # Lock connection to site
                     connection = Connection(self, ip, port, target_onion=site_onion, is_tracker_connection=is_tracker_connection)
                 else:
@@ -312,6 +313,7 @@ class ConnectionServer(object):
                     raise Exception("Connection event return error")
 
             except Exception as err:
+                #self.log.info("Connection error (%s, %s): %s", ip, port, Debug.formatException(err))
                 connection.close("%s Connect error: %s" % (ip, Debug.formatException(err)))
                 raise err
 
@@ -429,6 +431,21 @@ class ConnectionServer(object):
         ))
         return num_closed
 
+    # Returns True if we should slow down opening new connections as at the moment
+    # there are too many connections being established and not connected completely
+    # (not entered the message loop yet).
+    def shouldThrottleNewConnections(self):
+        threshold = config.simultaneous_connection_throttle_threshold
+        if len(self.connections) <= threshold:
+            return False
+        nr_connections_being_established = 0
+        for connection in self.connections[:]:  # Make a copy
+            if connection.connecting and not connection.connected and connection.type == "out":
+                nr_connections_being_established += 1
+                if nr_connections_being_established > threshold:
+                    return True
+        return False
+
     # Internet outage detection
     def updateOnlineStatus(self, connection, outgoing_activity=False, successful_activity=False):
 
diff --git a/src/File/FileServer.py b/src/File/FileServer.py
index ac4b8c55..66cefd39 100644
--- a/src/File/FileServer.py
+++ b/src/File/FileServer.py
@@ -401,6 +401,9 @@ class FileServer(ConnectionServer):
             self.sleep(1)
             self.waitForInternetOnline()
 
+            while self.isActiveMode() and self.shouldThrottleNewConnections():
+                self.sleep(1)
+
             if not self.isActiveMode():
                 break
 
@@ -463,6 +466,9 @@ class FileServer(ConnectionServer):
             self.sleep(short_timeout)
             self.waitForInternetOnline()
 
+            while self.isActiveMode() and self.shouldThrottleNewConnections():
+                self.sleep(1)
+
             if not self.isActiveMode():
                 break
 
@@ -509,6 +515,9 @@ class FileServer(ConnectionServer):
         while self.isActiveMode():
             self.sleep(long_timeout)
 
+            while self.isActiveMode() and self.shouldThrottleNewConnections():
+                self.sleep(1)
+
             if not self.isActiveMode():
                 break
 
@@ -591,6 +600,10 @@ class FileServer(ConnectionServer):
             threshold = self.internet_outage_threshold / 2.0
 
             self.sleep(threshold / 2.0)
+
+            while self.isActiveMode() and self.shouldThrottleNewConnections():
+                self.sleep(1)
+
             if not self.isActiveMode():
                 break