diff --git a/src/hev-exec.c b/src/hev-exec.c
index 5cabb76..6f81560 100644
--- a/src/hev-exec.c
+++ b/src/hev-exec.c
@@ -7,6 +7,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <signal.h>
 #include <unistd.h>
 #include <sys/wait.h>
@@ -30,6 +30,11 @@ static char iaddr[INET6_ADDRSTRLEN];
 static char oport[32];
 static char iport[32];
 static char ip4p[32];
+static unsigned int last_maddr[4];
+static unsigned int last_baddr[4];
+static unsigned short last_mport;
+static unsigned short last_bport;
+static int last_family;
 
 static void
 signal_handler (int signum)
@@ -73,6 +78,12 @@ hev_exec_run (int family, unsigned int maddr[4], unsigned short mport,
     path = hev_conf_path ();
     signal (SIGCHLD, signal_handler);
 
+    last_family = family;
+    memcpy (last_maddr, maddr, sizeof (last_maddr));
+    memcpy (last_baddr, baddr, sizeof (last_baddr));
+    last_mport = mport;
+    last_bport = bport;
+
     q = (unsigned char *)maddr;
     p = (unsigned char *)&mport;
 
@@ -113,3 +124,11 @@ hev_exec_run (int family, unsigned int maddr[4], unsigned short mport,
     hev_exec_fork_exec (&call);
 #endif
 }
+
+void
+hev_exec_ping (void)
+{
+    if (last_family)
+        hev_exec_run (last_family, last_maddr, last_mport, last_baddr,
+                      last_bport);
+}
diff --git a/src/hev-exec.h b/src/hev-exec.h
index dcbaee4..ed62b58 100644
--- a/src/hev-exec.h
+++ b/src/hev-exec.h
@@ -36,4 +36,6 @@ void hev_exec_init (void *stack);
 void hev_exec_run (int family, unsigned int maddr[4], unsigned short mport,
                    unsigned int baddr[4], unsigned short bport);
 
+void hev_exec_ping (void);
+
 #endif /* __HEV_EXEC_H__ */
diff --git a/src/hev-stun.c b/src/hev-stun.c
index 2916b72..de8cc3b 100644
--- a/src/hev-stun.c
+++ b/src/hev-stun.c
@@ -273,10 +273,10 @@ stun_bind (int fd, int mode, unsigned int baddr[4], int bport)
     handler ();
 
     exec = cmp_addr (family, maddr, mport, baddr, bport);
-    if (exec) {
+    if (exec)
         hev_conf_mport (ntohs (mport));
-        hev_exec_run (family, maddr, mport, baddr, bport);
-    }
+
+    hev_exec_run (family, maddr, mport, baddr, bport);
 
     return 0;
 }
diff --git a/src/hev-tnsk.c b/src/hev-tnsk.c
index a191c70..a4b4d7b 100644
--- a/src/hev-tnsk.c
+++ b/src/hev-tnsk.c
@@ -19,6 +19,7 @@
 #include "hev-misc.h"
 #include "hev-sock.h"
 #include "hev-stun.h"
+#include "hev-exec.h"
 #include "hev-tfwd.h"
 #include "hev-xnsk.h"
 
@@ -67,6 +68,7 @@ tnsk_keep_alive (int fd, const char *http)
             } else if (res <= 0) {
                 return;
             } else {
+                hev_exec_ping ();
                 misscnt = 0;
             }
         }
diff --git a/src/hev-ufwd.c b/src/hev-ufwd.c
index 9c5a226..a1d0303 100644
--- a/src/hev-ufwd.c
+++ b/src/hev-ufwd.c
@@ -222,6 +222,11 @@ server_task_entry (void *data)
             break;
         }
 
+        if ((len >= 5) && !memcmp (buf, "SMHP:", 5)) {
+            sendto (sfd, buf, len, 0, pa, alen);
+            continue;
+        }
+
         s = session_find (pa, alen);
         if (!s) {