diff --git a/config.py b/config.py
index 23297f2..966aa10 100644
--- a/config.py
+++ b/config.py
@@ -8,3 +8,7 @@
 
 # Tag for advertising, obtainable from @MTProxybot
 # AD_TAG = "3c09c680b76ee91a4c25ad51f742267d"
+
+# Uncommenting this do make a proxy harder to detect
+# But it can be incompatible with old clients
+# SECURE_ONLY = True
diff --git a/mtprotoproxy.py b/mtprotoproxy.py
index 1d83cb5..2787d51 100755
--- a/mtprotoproxy.py
+++ b/mtprotoproxy.py
@@ -144,17 +144,32 @@ def debug_signal(signum, frame):
 AD_TAG = bytes.fromhex(config.get("AD_TAG", ""))
 
 # load advanced settings
+# if IPv6 avaliable, use it by default
 PREFER_IPV6 = config.get("PREFER_IPV6", socket.has_ipv6)
 # disables tg->client trafic reencryption, faster but less secure
 FAST_MODE = config.get("FAST_MODE", True)
+# doesn't allow to connect in not-secure mode
+SECURE_ONLY = config.get("SECURE_ONLY", False)
+# delay in seconds between stats printing
 STATS_PRINT_PERIOD = config.get("STATS_PRINT_PERIOD", 600)
+# delay in seconds between middle proxy info updates
 PROXY_INFO_UPDATE_PERIOD = config.get("PROXY_INFO_UPDATE_PERIOD", 24*60*60)
+# max socket buffer size to the client direction, the more the faster, but more RAM hungry
 TO_CLT_BUFSIZE = config.get("TO_CLT_BUFSIZE", 16384)
+# max socket buffer size to the telegram servers direction
 TO_TG_BUFSIZE = config.get("TO_TG_BUFSIZE", 65536)
+# keepalive period for clients in secs
 CLIENT_KEEPALIVE = config.get("CLIENT_KEEPALIVE", 10*60)
+# drop client after this timeout if the handshake fail
 CLIENT_HANDSHAKE_TIMEOUT = config.get("CLIENT_HANDSHAKE_TIMEOUT", 10)
+# if client doesn't confirm data for this number of seconds, it is dropped
 CLIENT_ACK_TIMEOUT = config.get("CLIENT_ACK_TIMEOUT", 5*60)
+# telegram servers connect timeout in seconds
 TG_CONNECT_TIMEOUT = config.get("TG_CONNECT_TIMEOUT", 10)
+# listen address for IPv4
+LISTEN_ADDR_IPV4 = config.get("LISTEN_ADDR_IPV4", "0.0.0.0")
+# listen address for IPv6
+LISTEN_ADDR_IPV6 = config.get("LISTEN_ADDR_IPV6", "::")
 
 TG_DATACENTER_PORT = 443
 
@@ -588,6 +603,9 @@ async def handle_handshake(reader, writer):
         if proto_tag not in (PROTO_TAG_ABRIDGED, PROTO_TAG_INTERMEDIATE, PROTO_TAG_SECURE):
             continue
 
+        if SECURE_ONLY and proto_tag != PROTO_TAG_SECURE:
+            continue
+
         dc_idx = int.from_bytes(decrypted[DC_IDX_POS:DC_IDX_POS+2], "little", signed=True)
 
         reader = CryptoWrappedStreamReader(reader, decryptor)
@@ -1097,13 +1115,14 @@ def print_tg_info():
 
     for user, secret in sorted(USERS.items(), key=lambda x: x[0]):
         for ip in ip_addrs:
-            params = {"server": ip, "port": PORT, "secret": secret}
-            params_encodeded = urllib.parse.urlencode(params, safe=':')
-            print("{}: tg://proxy?{}".format(user, params_encodeded), flush=True)
+            if not SECURE_ONLY:
+                params = {"server": ip, "port": PORT, "secret": secret}
+                params_encodeded = urllib.parse.urlencode(params, safe=':')
+                print("{}: tg://proxy?{}".format(user, params_encodeded), flush=True)
 
             params = {"server": ip, "port": PORT, "secret": "dd" + secret}
             params_encodeded = urllib.parse.urlencode(params, safe=':')
-            print("{}: tg://proxy?{} (beta)".format(user, params_encodeded), flush=True)
+            print("{}: tg://proxy?{}".format(user, params_encodeded), flush=True)
 
 
 def loop_exception_handler(loop, context):
@@ -1153,12 +1172,12 @@ def main():
 
     reuse_port = hasattr(socket, "SO_REUSEPORT")
 
-    task_v4 = asyncio.start_server(handle_client_wrapper, '0.0.0.0', PORT,
+    task_v4 = asyncio.start_server(handle_client_wrapper, LISTEN_ADDR_IPV4, PORT,
                                    limit=TO_TG_BUFSIZE, reuse_port=reuse_port, loop=loop)
     server_v4 = loop.run_until_complete(task_v4)
 
     if socket.has_ipv6:
-        task_v6 = asyncio.start_server(handle_client_wrapper, '::', PORT,
+        task_v6 = asyncio.start_server(handle_client_wrapper, LISTEN_ADDR_IPV6, PORT,
                                        limit=TO_TG_BUFSIZE, reuse_port=reuse_port, loop=loop)
         server_v6 = loop.run_until_complete(task_v6)