diff --git a/app/src/main/jni/netguard/netguard.h b/app/src/main/jni/netguard/netguard.h
index 27d3b1f5..ba322402 100644
--- a/app/src/main/jni/netguard/netguard.h
+++ b/app/src/main/jni/netguard/netguard.h
@@ -50,10 +50,11 @@
 #define UDP_KEEP_TIMEOUT 60 // seconds
 
 #define TCP_INIT_TIMEOUT 30 // seconds ~net.inet.tcp.keepinit
-#define TCP_IDLE_TIMEOUT 3600 // seconds ~net.inet.tcp.keepidle
+#define TCP_IDLE_TIMEOUT 29 // seconds ~net.inet.tcp.keepidle
 #define TCP_CLOSE_TIMEOUT 30 // seconds
 #define TCP_KEEP_TIMEOUT 300 // seconds
 // https://en.wikipedia.org/wiki/Maximum_segment_lifetime
+#define TCP_KEEP_ALIVE 30 // seconds
 
 #define UID_DELAY 1 // milliseconds
 #define UID_DELAYTRY 10 // milliseconds
diff --git a/app/src/main/jni/netguard/tcp.c b/app/src/main/jni/netguard/tcp.c
index 51af47d3..a6179251 100644
--- a/app/src/main/jni/netguard/tcp.c
+++ b/app/src/main/jni/netguard/tcp.c
@@ -128,8 +128,11 @@ int monitor_tcp_session(const struct arguments *args, struct ng_session *s, int
     }
     else if (s->tcp.state == TCP_ESTABLISHED || s->tcp.state == TCP_CLOSE_WAIT) {
 
+        uint32_t rwindow = get_receive_window(s);
+        uint32_t swindow = get_send_window(&s->tcp);
+
         // Check for incoming data
-        if (get_send_window(&s->tcp) > 0)
+        if (swindow > 0)
             events = events | EPOLLIN;
         else {
             recheck = 1;
@@ -153,6 +156,19 @@ int monitor_tcp_session(const struct arguments *args, struct ng_session *s, int
             else
                 recheck = 1;
         }
+
+        // Keep alive
+        if (rwindow > 0 && swindow > 0) {
+            long long ms = get_ms();
+            if (s->tcp.time + TCP_KEEP_ALIVE < time(NULL) &&
+                ms - s->tcp.last_keep_alive > TCP_KEEP_ALIVE * 1000) {
+                s->tcp.last_keep_alive = ms;
+                log_android(ANDROID_LOG_WARN, "Sending keep alive");
+                s->tcp.remote_seq--;
+                write_ack(args, &s->tcp);
+                s->tcp.remote_seq++;
+            }
+        }
     }
 
     if (events != s->ev.events) {