diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7eed1d4..7846055 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,6 +2,7 @@ cmake_minimum_required(VERSION 3.7)
 project(udp2raw_tunnel)
 
 set(CMAKE_CXX_STANDARD 11)
+set_source_files_properties(lib/aes.c lib/md5.c PROPERTIES LANGUAGE CXX )
 
 set(SOURCE_FILES
         lib/aes.c
@@ -13,5 +14,6 @@ set(SOURCE_FILES
         network.cpp
         )
 set(CMAKE_CXX_FLAGS "-Wall -Wextra -Wno-unused-variable -Wno-unused-parameter -static")
-set(CMAKE_LINK_LIBRARY_FLAG "-lrt")
-add_executable(udp2raw_tunnel ${SOURCE_FILES})
\ No newline at end of file
+#set(CMAKE_LINK_LIBRARY_FLAG "-lrt")
+add_executable(udp2raw_tunnel ${SOURCE_FILES})
+target_link_libraries(udp2raw_tunnel rt)
diff --git a/common.h b/common.h
index e4c7875..89d5f46 100644
--- a/common.h
+++ b/common.h
@@ -71,7 +71,7 @@ const u32_t client_retry_interval=1000;
 const u32_t server_handshake_timeout=10000;// this should be much longer than clients. client retry initially ,server retry passtively
 
 const int conv_clear_ratio=10;  //conv grabage collecter check 1/10 of all conv one time
-const int conn_clear_ratio=10;
+const int conn_clear_ratio=30;
 const int conv_clear_min=5;
 const int conn_clear_min=1;
 
diff --git a/makefile b/makefile
index e406b69..c428803 100755
--- a/makefile
+++ b/makefile
@@ -4,7 +4,7 @@ FLAGS2= -O3
 all:
 	sudo killall udp2raw||true
 	sleep 0.2
-	g++ main.cpp -o udp2raw  -static  -ggdb -I. lib/aes.c lib/md5.c encrypt.cpp log.cpp network.cpp common.cpp -lrt -std=c++11    ${FLAGS} ${FLAGS2}
+	gcc main.cpp -o udp2raw  -static  -ggdb -I. lib/aes.c lib/md5.c encrypt.cpp log.cpp network.cpp common.cpp -lrt -std=c++11    ${FLAGS} ${FLAGS2}
 #	${ccmips} main.cpp -o udp2raw_ar71xx  -lrt -I. lib/aes.c lib/md5.c encrypt.cpp log.cpp network.cpp common.cpp -std=c++11 ${FLAGS} ${FLAGS2}
 fast:
 	sudo killall udp2raw||true