diff --git a/contrib/spoa_server/spoa.c b/contrib/spoa_server/spoa.c
index e484315..53fc759 100644
--- a/contrib/spoa_server/spoa.c
+++ b/contrib/spoa_server/spoa.c
@@ -156,26 +156,30 @@
 check_ipv4_reputation(struct worker *w, struct in_addr *ipv4)
 {
 	char str[INET_ADDRSTRLEN];
+	unsigned int score;
 
 	if (inet_ntop(AF_INET, ipv4, str, INET_ADDRSTRLEN) == NULL)
 		return;
 
-	w->ip_score = random() % 100;
+	score = random() % 100;
+	set_var_uint32(w, "ip_score", 8, SPOE_SCOPE_SESS, score);
 
-	DEBUG("  IP score for %.*s is: %d", INET_ADDRSTRLEN, str, w->ip_score);
+	DEBUG("  IP score for %.*s is: %d", INET_ADDRSTRLEN, str, score);
 }
 
 static void
 check_ipv6_reputation(struct worker *w, struct in6_addr *ipv6)
 {
 	char str[INET6_ADDRSTRLEN];
+	unsigned int score;
 
 	if (inet_ntop(AF_INET6, ipv6, str, INET6_ADDRSTRLEN) == NULL)
 		return;
 
-	w->ip_score = random() % 100;
+	score = random() % 100;
+	set_var_uint32(w, "ip_score", 8, SPOE_SCOPE_SESS, score);
 
-	DEBUG("  IP score for %.*s is: %d", INET6_ADDRSTRLEN, str, w->ip_score);
+	DEBUG("  IP score for %.*s is: %d", INET6_ADDRSTRLEN, str, score);
 }
 
 static int
@@ -700,6 +704,159 @@
 	return -1;
 }
 
+/* Encode a ACK frame to send it to HAProxy. It returns -1 if an error occurred,
+ * the number of written bytes otherwise. */
+static void prepare_agentack(struct worker *w)
+{
+	w->ack_len = 0;
+
+	/* Frame type */
+	w->ack[w->ack_len++] = SPOE_FRM_T_AGENT_ACK;
+
+	/* No flags for now */
+	memset(w->ack + w->ack_len, 0, 4); /* No flags */
+	w->ack_len += 4;
+
+	/* Set stream-id and frame-id for ACK frames */
+	w->ack_len += encode_spoe_varint(w->stream_id, w->ack + w->ack_len);
+	w->ack_len += encode_spoe_varint(w->frame_id, w->ack + w->ack_len);
+}
+
+static inline
+int set_var_name(struct worker *w, const char *name, int name_len, unsigned char scope)
+{
+	w->ack[w->ack_len++] = SPOE_ACT_T_SET_VAR; /* Action type */
+	w->ack[w->ack_len++] = 3;                  /* Number of args */
+	w->ack[w->ack_len++] = scope;              /* Arg 1: the scope */
+	w->ack_len += encode_spoe_string(name, name_len, w->ack+w->ack_len); /* Arg 2: variable name */
+	return 1;
+}
+
+int set_var_null(struct worker *w,
+                 const char *name, int name_len,
+                 unsigned char scope)
+{
+	if (!set_var_name(w, name, name_len, scope))
+		return 0;
+	w->ack[w->ack_len++] = SPOE_DATA_T_NULL;
+	return 1;
+}
+
+int set_var_bool(struct worker *w,
+                 const char *name, int name_len,
+                 unsigned char scope, bool value)
+{
+	if (!set_var_name(w, name, name_len, scope))
+		return 0;
+	w->ack[w->ack_len++] = SPOE_DATA_T_BOOL | (!!value << 4);
+	return 1;
+}
+
+static inline
+int set_var_int(struct worker *w,
+                const char *name, int name_len,
+                unsigned char scope, int type, uint64_t value)
+{
+	if (!set_var_name(w, name, name_len, scope))
+		return 0;
+	w->ack[w->ack_len++] = SPOE_DATA_T_UINT32;
+	w->ack_len += encode_spoe_varint(value, w->ack+w->ack_len);   /* Arg 3: variable value */
+	return 1;
+}
+
+int set_var_uint32(struct worker *w,
+                   const char *name, int name_len,
+                   unsigned char scope, uint32_t value)
+{
+	return set_var_int(w, name, name_len, scope, SPOE_DATA_T_UINT32, value);
+}
+
+int set_var_int32(struct worker *w,
+                  const char *name, int name_len,
+                  unsigned char scope, int32_t value)
+{
+	return set_var_int(w, name, name_len, scope, SPOE_DATA_T_INT32, value);
+}
+
+int set_var_uint64(struct worker *w,
+                   const char *name, int name_len,
+                   unsigned char scope, uint64_t value)
+{
+	return set_var_int(w, name, name_len, scope, SPOE_DATA_T_INT32, value);
+}
+
+int set_var_int64(struct worker *w,
+                  const char *name, int name_len,
+                  unsigned char scope, int64_t value)
+{
+	return set_var_int(w, name, name_len, scope, SPOE_DATA_T_INT32, value);
+}
+
+int set_var_ipv4(struct worker *w,
+                 const char *name, int name_len,
+                 unsigned char scope,
+                 struct in_addr *ipv4)
+{
+	if (!set_var_name(w, name, name_len, scope))
+		return 0;
+	w->ack[w->ack_len++] = SPOE_DATA_T_IPV4;
+	memcpy(w->ack+w->ack_len, ipv4, 4);
+	w->ack_len += 4;
+	return 1;
+}
+
+int set_var_ipv6(struct worker *w,
+                 const char *name, int name_len,
+                 unsigned char scope,
+                 struct in6_addr *ipv6)
+{
+	if (!set_var_name(w, name, name_len, scope))
+		return 0;
+	w->ack[w->ack_len++] = SPOE_DATA_T_IPV6;
+	memcpy(w->ack+w->ack_len, ipv6, 16);
+	w->ack_len += 16;
+	return 1;
+}
+
+static inline
+int set_var_buf(struct worker *w,
+                const char *name, int name_len,
+                unsigned char scope, int type,
+                const char *str, int str_len)
+{
+	if (!set_var_name(w, name, name_len, scope))
+		return 0;
+	w->ack[w->ack_len++] = type;
+	w->ack_len += encode_spoe_string(str, str_len, w->ack+w->ack_len);
+	return 1;
+}
+
+int set_var_string(struct worker *w,
+                   const char *name, int name_len,
+                   unsigned char scope,
+                   const char *str, int strlen)
+{
+	return set_var_buf(w, name, name_len, scope, SPOE_DATA_T_STR, str, strlen);
+}
+
+int set_var_bin(struct worker *w,
+                const char *name, int name_len,
+                unsigned char scope,
+                const char *str, int strlen)
+{
+	return set_var_buf(w, name, name_len, scope, SPOE_DATA_T_BIN, str, strlen);
+}
+
+/* This function is a little bit ugly,
+ * TODO: improve the response without copying the bufer
+ */
+static int commit_agentack(struct worker *w)
+{
+	memcpy(w->buf, w->ack, w->ack_len);
+	w->len = w->ack_len;
+	return 1;
+}
+
 /* Decode a NOTIFY frame received from HAProxy. It returns -1 if an error
  * occurred, 0 if the frame must be skipped, otherwise the number of read
  * bytes. */
@@ -737,6 +894,9 @@
 	DEBUG("Notify frame received: stream-id=%u - frame-id=%u",
 	      w->stream_id, w->frame_id);
 
+	/* Prepara ack, if the processing fails tha ack will be cancelled */
+	prepare_agentack(w);
+
 	/* Loop on messages */
 	while (idx < w->len) {
 		char    *str;
@@ -840,39 +1000,6 @@
 	return idx;
 }
 
-/* Encode a ACK frame to send it to HAProxy. It returns -1 if an error occurred,
- * the number of written bytes otherwise. */
-static int
-prepare_agentack(struct worker *w)
-{
-	int idx = 0;
-
-	/* Frame type */
-	w->buf[idx++] = SPOE_FRM_T_AGENT_ACK;
-
-	/* No flags for now */
-	memset(w->buf+idx, 0, 4); /* No flags */
-	idx += 4;
-
-	/* Set stream-id and frame-id for ACK frames */
-	idx += encode_spoe_varint(w->stream_id, w->buf+idx);
-	idx += encode_spoe_varint(w->frame_id, w->buf+idx);
-
-	/* Data */
-	if (w->ip_score == -1)
-		goto out;
-
-	w->buf[idx++] = SPOE_ACT_T_SET_VAR;                   /* Action type */
-	w->buf[idx++] = 3;                                    /* Number of args */
-	w->buf[idx++] = SPOE_SCOPE_SESS;                      /* Arg 1: the scope */
-	idx += encode_spoe_string("ip_score", 8, w->buf+idx); /* Arg 2: variable name */
-	w->buf[idx++] = SPOE_DATA_T_UINT32;
-	idx += encode_spoe_varint(w->ip_score, w->buf+idx);   /* Arg 3: variable value */
-out:
-	w->len = idx;
-	return idx;
-}
-
 /* Encode a DISCONNECT frame to send it to HAProxy. It returns -1 if an error
  * occurred, the number of written bytes otherwise. */
 static int
@@ -957,7 +1084,7 @@
 		LOG("Failed to handle Haproxy NOTIFY frame");
 		goto error_or_quit;
 	}
-	if (prepare_agentack(w) < 0) {
+	if (commit_agentack(w) < 0) {
 		LOG("Failed to prepare Agent ACK frame");
 		goto error_or_quit;
 	}
@@ -1022,7 +1149,6 @@
 		if (w.healthcheck == true)
 			goto close;
 		while (1) {
-			w.ip_score = -1;
 			if (notify_ack_roundtip(csock, &w) < 0)
 				break;
 		}