diff --git a/src/conf.c b/src/conf.c
index 0d55f64..eb2ed0b 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -72,11 +72,13 @@ void config_address_destroy(void)
 int config_address(char *value)
 {
 	struct dns_address *address = NULL;
+	struct dns_address *oldaddress;
 	char ip[MAX_IP_LEN];
 	char domain_key[DNS_MAX_CONF_CNAME_LEN];
 	char *begin = NULL;
 	char *end = NULL;
 	int len = 0;
+	int port;
 	struct sockaddr_storage addr;
 	socklen_t addr_len = sizeof(addr);
 	char type = '4';
@@ -101,9 +103,12 @@ int config_address(char *value)
 	len = end - begin;
 	memcpy(address->domain, begin, len);
 	address->domain[len] = 0;
-	strncpy(ip, end + 1, MAX_IP_LEN);
 	reverse_string(domain_key + 1, address->domain, len);
 
+	if (parse_ip(end + 1, ip, &port) != 0) {
+		goto errout;
+	}
+
 	if (getaddr_by_host(ip, (struct sockaddr *)&addr, &addr_len) != 0) {
 		goto errout;
 	}
@@ -135,7 +140,10 @@ int config_address(char *value)
 
 	domain_key[0] = type;
 	len++;
-	art_insert(&dns_conf_address, (unsigned char *)domain_key, len, address);
+	oldaddress = art_insert(&dns_conf_address, (unsigned char *)domain_key, len, address);
+	if (oldaddress) {
+		free(oldaddress);
+	}
 
 	return 0;
 errout:
@@ -277,4 +285,4 @@ errout:
 		fclose(fp);
 	}
 	return -1;
-}
\ No newline at end of file
+}
diff --git a/src/dns.c b/src/dns.c
index c8cf929..2df3966 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -412,6 +412,95 @@ int dns_get_RAW(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, void *
 	return 0;
 }
 
+int dns_add_OPT(struct dns_packet *packet, dns_rr_type type, unsigned short opt_code, unsigned short opt_len, struct dns_opt *opt)
+{
+	// TODO
+	
+	int maxlen = 0;
+	int len = 0;
+	struct dns_data_context data_context;
+	int total_len = sizeof(*opt) + opt->length;
+	int ttl = 0;
+
+	/*
+    +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+  0: |                          OPTION-CODE                          |
+     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+  2: |                         OPTION-LENGTH                         |
+     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+  4: |                                                               |
+     /                          OPTION-DATA                          /
+     /                                                               /
+     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+	*/
+	unsigned char *data = _dns_add_rrs_start(packet, &maxlen);
+	if (data == NULL) {
+		return -1;
+	}
+
+	if (total_len > maxlen) {
+		return -1;
+	}
+
+	data_context.data = data;
+	data_context.ptr = data;
+	data_context.maxsize = maxlen;
+
+	ttl = (opt_code << 16) | opt_len;
+
+	/* add rr head */
+	len = _dns_add_rr_head(&data_context, "", type, DNS_C_IN, ttl, total_len);
+	if (len < 0) {
+		return -1;
+	}
+
+	/* add rr data */
+	memcpy(data_context.ptr, opt, total_len);
+	data_context.ptr += total_len;
+	len = data_context.ptr - data_context.data;
+
+	return dns_rr_add_end(packet, type, DNS_T_OPT, len);
+}
+
+int dns_get_OPT(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt *opt, int *opt_maxlen)
+{
+	// TODO
+
+	int qtype = 0;
+	int qclass = 0;
+	int rr_len = 0;
+	int ret = 0;
+	struct dns_data_context data_context;
+	char domain[DNS_MAX_CNAME_LEN];
+	int maxsize = DNS_MAX_CNAME_LEN;
+	int ttl = 0;
+	unsigned char *data = rrs->data;
+
+	data_context.data = data;
+	data_context.ptr = data;
+	data_context.maxsize = rrs->len;
+
+	/* get rr head */
+	ret = _dns_get_rr_head(&data_context, domain, maxsize, &qtype, &qclass, &ttl, &rr_len);
+	if (ret < 0) {
+		return -1;
+	}
+
+	if (qtype != rrs->type || rr_len > *opt_len) {
+		return -1;
+	}
+
+	/* get rr data */
+	*opt_code = ttl >> 16;
+	*opt_len = ttl & 0xFFFF;
+	memcpy(opt, data_context.ptr, rr_len);
+	data_context.ptr += rr_len;
+	*opt_maxlen = rr_len;
+
+	return 0;
+}
+
+
 int dns_add_CNAME(struct dns_packet *packet, dns_rr_type type, char *domain, int ttl, char *cname)
 {
 	int rr_len = strnlen(cname, DNS_MAX_CNAME_LEN) + 1;
@@ -546,6 +635,47 @@ int dns_get_SOA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, struct
 	return 0;
 }
 
+int dns_add_OPT_ECS(struct dns_packet *packet, dns_rr_type type, struct dns_opt_ecs *ecs)
+{
+	// TODO
+	
+	unsigned char opt_data[DNS_MAX_OPT_LEN];
+	struct dns_opt *opt = (struct dns_opt *)opt_data;
+	int len = 0;
+
+	opt->code = DNS_OPT_T_ECS;
+	opt->length = sizeof(*ecs);
+	memcpy(opt->data, ecs, sizeof(*ecs));
+
+	/* ecs size 4 + bit of address*/
+	len = sizeof(*opt) + 4;
+	len += (ecs->source_prefix / 8);
+	len += (ecs->source_prefix % 8 > 0) ? 1 : 0;
+
+	return dns_add_OPT(packet, type, DNS_OPT_T_ECS, len, opt);
+}
+
+int dns_get_OPT_ECS(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt_ecs *ecs)
+{
+	// TODO
+	
+	unsigned char opt_data[DNS_MAX_OPT_LEN];
+	struct dns_opt *opt = (struct dns_opt *)opt_data;
+	int len = sizeof(opt_data);
+
+	if (dns_get_OPT(rrs, opt_code, opt_len, opt, &len) != 0) {
+		return -1;
+	}
+
+	if (opt->code != DNS_OPT_T_ECS) {
+		return -1;
+	}
+
+	memcpy(ecs, opt->data, opt->length);
+
+	return 0;
+}
+
 /*
  * Format:
  * |DNS_NAME\0(string)|qtype(short)|qclass(short)|
@@ -1074,6 +1204,108 @@ int _dns_encode_SOA(struct dns_context *context, struct dns_rrs *rrs)
 	return 0;
 }
 
+
+static int _dns_decode_opt_ecs(struct dns_context *context, struct dns_opt_ecs *ecs)
+{
+	// TODO
+	
+	int len = 0;
+	if (_dns_left_len(context) < 4) {
+		return -1;
+	}
+
+	ecs->family = dns_read_short(&context->ptr);
+	ecs->source_prefix = dns_read_char(&context->ptr);
+	ecs->scope_prefix = dns_read_char(&context->ptr);
+	len = (ecs->source_prefix / 8);
+	len += (ecs->source_prefix % 8 > 0) ? 1 : 0;
+
+	if (_dns_left_len(context) < len) {
+		return -1;
+	}
+
+	memcpy(ecs->addr, context->ptr, len);
+	context->ptr += len;
+
+	return 0;
+}
+
+int _dns_encode_OPT(struct dns_context *context, struct dns_rrs *rrs)
+{
+	// TODO
+	
+	return 0;
+}
+
+static int _dns_decode_opt(struct dns_context *context, dns_rr_type type, unsigned int ttl, int rr_len)
+{
+	unsigned short opt_code;
+	unsigned short opt_len;
+	unsigned short ercode = (ttl >> 16) & 0xFFFF;
+	unsigned short ever = (ttl) & 0xFFFF;
+	unsigned char *start = context->ptr;
+	struct dns_packet *packet = context->packet;
+	int ret = 0;
+	/*
+	     Field Name   Field Type     Description
+     ------------------------------------------------------
+     NAME         domain name    empty (root domain)
+     TYPE         u_int16_t      OPT
+     CLASS        u_int16_t      sender's UDP payload size
+     TTL          u_int32_t      extended RCODE and flags
+     RDLEN        u_int16_t      describes RDATA
+     RDATA        octet stream   {attribute,value} pairs
+
+	                 +0 (MSB)                            +1 (LSB)
+     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+  0: |                          OPTION-CODE                          |
+     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+  2: |                         OPTION-LENGTH                         |
+     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+  4: |                                                               |
+     /                          OPTION-DATA                          /
+     /                                                               /
+     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+
+	TTL
+                 +0 (MSB)                            +1 (LSB)
+      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+   0: |         EXTENDED-RCODE        |            VERSION            |
+      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+   2: |                               Z                               |
+      +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+	*/
+
+	if (ercode != 0) {
+		tlog(TLOG_ERROR, "extend rcode invalid.");
+		return -1;
+	}
+	ever = ever;
+
+	while (context->ptr - start < rr_len) {
+		opt_code = dns_read_short(&context->ptr);
+		opt_len = dns_read_short(&context->ptr);
+		switch (opt_code) {
+		case DNS_OPT_T_ECS: {
+			struct dns_opt_ecs ecs;
+			ret = _dns_decode_opt_ecs(context, &ecs);
+			if (ret != 0 ) {
+				tlog(TLOG_ERROR, "decode ecs failed.");
+				return -1;
+			}
+
+			ret = dns_add_OPT_ECS(packet, type, &ecs);
+		} break;
+		default:
+			context->ptr += opt_len;
+			tlog(TLOG_DEBUG, "DNS opt type = %d not supported", opt_code);
+			break;
+		}				
+	}
+
+	return 0;
+}
+
 static int _dns_decode_qd(struct dns_context *context)
 {
 	struct dns_packet *packet = context->packet;
@@ -1200,6 +1432,19 @@ static int _dns_decode_an(struct dns_context *context, dns_rr_type type)
 			return -1;
 		}
 	} break;
+	case DNS_T_OPT: {
+		unsigned char  *opt_start = context->ptr;
+		ret = _dns_decode_opt(context, type, ttl, rr_len);
+		if (ret < 0) {
+			tlog(TLOG_ERROR, "decode opt failed, %s", domain);
+			return -1;
+		}
+
+		if (context->ptr - opt_start != rr_len) {
+			tlog(TLOG_ERROR, "opt length mitchmatch, %s\n", domain);
+			return -1;
+		}
+	} break;
 	default:
 		context->ptr += rr_len;
 		tlog(TLOG_DEBUG, "DNS type = %d not supported", qtype);
@@ -1263,6 +1508,12 @@ static int _dns_encode_an(struct dns_context *context, struct dns_rrs *rrs)
 			return -1;
 		}
 		break;
+	case DNS_T_OPT:
+		ret = _dns_encode_OPT(context, rrs);
+		if (ret < 0) {
+			return -1;
+		}
+		break;
 	default:
 		break;
 	}
diff --git a/src/dns.h b/src/dns.h
index 6166e51..266f94a 100644
--- a/src/dns.h
+++ b/src/dns.h
@@ -9,6 +9,7 @@
 #define DNS_RR_A_LEN 4
 #define DNS_RR_AAAA_LEN 16
 #define DNS_MAX_CNAME_LEN 256
+#define DNS_MAX_OPT_LEN 256
 #define DNS_IN_PACKSIZE (512 * 4)
 #define DNS_PACKSIZE (512 * 8)
 
@@ -44,6 +45,11 @@ typedef enum dns_type {
 	DNS_T_ALL = 255
 } dns_type_t;
 
+typedef enum dns_opt_code {
+	DNS_OPT_T_ECS = 8,
+	DNS_OPT_T_ALL = 255
+} dns_opt_code_t;
+
 typedef enum dns_opcode {
 	DNS_OP_QUERY = 0,
 	DNS_OP_IQUERY = 1,
@@ -128,7 +134,24 @@ struct dns_soa {
 	unsigned int expire;
 	unsigned int minimum;
 } __attribute__((packed));
-;
+
+#define DNS_OPT_ECS_FAMILY_IPV4 1
+#define DNS_OPT_ECS_FAMILY_IPV6 2
+
+/* OPT ECS */
+struct dns_opt_ecs {
+	unsigned short family;
+	unsigned char source_prefix;
+	unsigned char scope_prefix;
+	unsigned char addr[DNS_RR_AAAA_LEN];
+};
+
+/* OPT */
+struct dns_opt {
+	unsigned short code;
+	unsigned short length;
+	unsigned char data[0];
+} __attribute__((packed));
 
 struct dns_rrs *dns_get_rrs_next(struct dns_packet *packet, struct dns_rrs *rrs);
 struct dns_rrs *dns_get_rrs_start(struct dns_packet *packet, dns_rr_type type, int *count);
@@ -156,6 +179,12 @@ int dns_get_AAAA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, unsig
 
 int dns_add_SOA(struct dns_packet *packet, dns_rr_type type, char *domain, int ttl, struct dns_soa *soa);
 int dns_get_SOA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, struct dns_soa *soa);
+
+int dns_add_OPT(struct dns_packet *packet, dns_rr_type type, unsigned short opt_code, unsigned short opt_len, struct dns_opt *opt);
+int dns_get_OPT(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt *opt, int *opt_maxlen);
+
+int dns_add_OPT_ECS(struct dns_packet *packet, dns_rr_type type, struct dns_opt_ecs *ecs);
+int dns_get_OPT_ECS(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt_ecs *ecs);
 /*
  * Packet operation
  */
diff --git a/src/dns_server.c b/src/dns_server.c
index 6080e70..49b29b2 100644
--- a/src/dns_server.c
+++ b/src/dns_server.c
@@ -49,6 +49,7 @@
 #include <unistd.h>
 
 #define DNS_MAX_EVENTS 256
+#define DNS_SERVER_TMOUT_TTL (3 * 60)
 
 /* dns server data */
 struct dns_server {
@@ -268,11 +269,25 @@ int _dns_server_request_complete(struct dns_request *request)
 	if (request->qtype == DNS_T_A) {
 		tlog(TLOG_INFO, "result: %s, rcode: %d,  %d.%d.%d.%d\n", request->domain, request->rcode, request->ipv4_addr[0], request->ipv4_addr[1],
 			 request->ipv4_addr[2], request->ipv4_addr[3]);
+
+		if (request->has_ipv4) {
+			if (request->has_ping_result == 0 && request->ttl_v4 > DNS_SERVER_TMOUT_TTL) {
+				request->ttl_v4 = DNS_SERVER_TMOUT_TTL;
+			}
+		}
+		dns_cache_insert(request->domain, request->ttl_v4, DNS_T_A, request->ipv4_addr, DNS_RR_A_LEN);
 	} else if (request->qtype == DNS_T_AAAA) {
 		tlog(TLOG_INFO, "result :%s, rcode: %d,  %.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x", request->domain, request->rcode,
 			 request->ipv6_addr[0], request->ipv6_addr[1], request->ipv6_addr[2], request->ipv6_addr[3], request->ipv6_addr[4], request->ipv6_addr[5],
 			 request->ipv6_addr[6], request->ipv6_addr[7], request->ipv6_addr[8], request->ipv6_addr[9], request->ipv6_addr[10], request->ipv6_addr[11],
 			 request->ipv6_addr[12], request->ipv6_addr[13], request->ipv6_addr[14], request->ipv6_addr[15]);
+
+		if (request->has_ipv6) {
+			if (request->has_ping_result == 0 && request->ttl_v6 > DNS_SERVER_TMOUT_TTL) {
+				request->ttl_v6 = DNS_SERVER_TMOUT_TTL;
+			}
+			dns_cache_insert(request->domain, request->ttl_v6, DNS_T_AAAA, request->ipv6_addr, DNS_RR_AAAA_LEN);
+		}
 	}
 
 	_dns_reply(request);
@@ -333,7 +348,6 @@ void _dns_server_ping_result(struct ping_host_struct *ping_host, const char *hos
 {
 	struct dns_request *request = userptr;
 	int may_complete = 0;
-	int addr_type = 0;
 
 	if (request == NULL) {
 		return;
@@ -355,7 +369,6 @@ void _dns_server_ping_result(struct ping_host_struct *ping_host, const char *hos
 			request->ping_ttl_v4 = rtt;
 			request->has_ipv4 = 1;
 			memcpy(request->ipv4_addr, &addr_in->sin_addr.s_addr, 4);
-			addr_type = 4;
 		}
 	} break;
 	case AF_INET6: {
@@ -366,14 +379,12 @@ void _dns_server_ping_result(struct ping_host_struct *ping_host, const char *hos
 				request->ping_ttl_v4 = rtt;
 				request->has_ipv4 = 1;
 				memcpy(request->ipv4_addr, addr_in6->sin6_addr.s6_addr + 12, 4);
-				addr_type = 4;
 			}
 		} else {
 			if (request->ping_ttl_v6 > rtt) {
 				request->ping_ttl_v6 = rtt;
 				request->has_ipv6 = 1;
 				memcpy(request->ipv6_addr, addr_in6->sin6_addr.s6_addr, 16);
-				addr_type = 6;
 			}
 		}
 	} break;
@@ -396,11 +407,6 @@ void _dns_server_ping_result(struct ping_host_struct *ping_host, const char *hos
 	if (may_complete) {
 		_dns_server_request_complete(request);
 		_dns_server_request_remove(request);
-		if (addr_type == 4) {
-			dns_cache_insert(request->domain, request->ttl_v4, DNS_T_A, request->ipv4_addr, DNS_RR_A_LEN);
-		} else if (addr_type == 6) {
-			dns_cache_insert(request->domain, request->ttl_v6, DNS_T_AAAA, request->ipv6_addr, DNS_RR_AAAA_LEN);
-		}
 	}
 }
 
@@ -508,6 +514,10 @@ static int _dns_server_process_answer(struct dns_request *request, char *domain,
 					memcpy(request->ipv4_addr, addr, DNS_RR_A_LEN);
 					request->ttl_v4 = ttl;
 					request->has_ipv4 = 1;
+				} else {
+					if (ttl < request->ttl_v4) {
+						request->ttl_v4 = ttl;
+					}
 				}
 				if (_dns_ip_address_check_add(request, addr, DNS_T_A) != 0) {
 					_dns_server_request_release(request);
@@ -539,6 +549,10 @@ static int _dns_server_process_answer(struct dns_request *request, char *domain,
 					memcpy(request->ipv6_addr, addr, DNS_RR_AAAA_LEN);
 					request->ttl_v6 = ttl;
 					request->has_ipv6 = 1;
+				} else {
+					if (ttl < request->ttl_v6) {
+						request->ttl_v6 = ttl;
+					}
 				}
 
 				if (_dns_ip_address_check_add(request, addr, DNS_T_AAAA) != 0) {
@@ -546,7 +560,7 @@ static int _dns_server_process_answer(struct dns_request *request, char *domain,
 					break;
 				}
 
-				sprintf(name, "%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x", addr[0], addr[1], addr[2], addr[3], addr[4], addr[5],
+				sprintf(ip, "%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x:%.2x%.2x", addr[0], addr[1], addr[2], addr[3], addr[4], addr[5],
 						addr[6], addr[7], addr[8], addr[9], addr[10], addr[11], addr[12], addr[13], addr[14], addr[15]);
 
 				if (_dns_server_ping(request, ip) != 0) {
@@ -702,7 +716,7 @@ static struct dns_address *_dns_server_get_address_by_domain(char *domain, int q
 	domain_key[0] = type;
 	domain_len++;
 
-	return art_substring(&dns_conf_address, (unsigned char *)domain_key, domain_len);;
+	return art_substring(&dns_conf_address, (unsigned char *)domain_key, domain_len);
 }
 
 static int _dns_server_process_address(struct dns_request *request, struct dns_packet *packet)
@@ -745,7 +759,7 @@ errout:
 static int _dns_server_process_cache(struct dns_request *request, struct dns_packet *packet)
 {
 	struct dns_cache *dns_cache = NULL;
-	
+
 	dns_cache = dns_cache_get(request->domain, request->qtype);
 	if (dns_cache == NULL) {
 		goto errout;
diff --git a/src/lib/art.c b/src/lib/art.c
index 7ac67e2..88994bb 100644
--- a/src/lib/art.c
+++ b/src/lib/art.c
@@ -170,9 +170,9 @@ static art_node** find_child(art_node *n, unsigned char c) {
         case NODE4:
             p.p1 = (art_node4*)n;
             for (i=0 ; i < n->num_children; i++) {
-		/* this cast works around a bug in gcc 5.1 when unrolling loops
-		 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59124
-		 */
+        /* this cast works around a bug in gcc 5.1 when unrolling loops
+         * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59124
+         */
                 if (((unsigned char*)p.p1->keys)[i] == c)
                     return &p.p1->children[i];
             }
@@ -421,8 +421,8 @@ static void add_child48(art_node48 *n, art_node **ref, unsigned char c, void *ch
         n->n.num_children++;
     } else {
         art_node256 *new_node = (art_node256*)alloc_node(NODE256);
-		int i;
-		for (i=0;i<256;i++) {
+        int i;
+        for (i=0;i<256;i++) {
             if (n->keys[i]) {
                 new_node->children[i] = n->children[n->keys[i] - 1];
             }
@@ -461,8 +461,8 @@ static void add_child16(art_node16 *n, art_node **ref, unsigned char c, void *ch
         #else
             // Compare the key to all 16 stored keys
             unsigned bitfield = 0;
-			int i;
-			for (i = 0; i < 16; ++i) {
+            int i;
+            for (i = 0; i < 16; ++i) {
                 if (c < n->keys[i])
                     bitfield |= (1 << i);
             }
@@ -489,9 +489,9 @@ static void add_child16(art_node16 *n, art_node **ref, unsigned char c, void *ch
 
     } else {
         art_node48 *new_node = (art_node48*)alloc_node(NODE48);
-		int i;
+        int i;
 
-		// Copy the child pointers and populate the key map
+        // Copy the child pointers and populate the key map
         memcpy(new_node->children, n->children,
                 sizeof(void*)*n->n.num_children);
         for (i=0;i<n->n.num_children;i++) {
@@ -688,8 +688,8 @@ static void remove_child256(art_node256 *n, art_node **ref, unsigned char c) {
         copy_header((art_node*)new_node, (art_node*)n);
 
         int pos = 0;
-		int i;
-		for (i=0;i<256;i++) {
+        int i;
+        for (i=0;i<256;i++) {
             if (n->children[i]) {
                 new_node->children[pos] = n->children[i];
                 new_node->keys[i] = pos + 1;
@@ -712,8 +712,8 @@ static void remove_child48(art_node48 *n, art_node **ref, unsigned char c) {
         copy_header((art_node*)new_node, (art_node*)n);
 
         int child = 0;
-		int i;
-		for (i=0;i<256;i++) {
+        int i;
+        for (i=0;i<256;i++) {
             pos = n->keys[i];
             if (pos) {
                 new_node->keys[child] = i;
@@ -858,8 +858,8 @@ static int recursive_iter(art_node *n, art_callback cb, void *data) {
     }
 
     int idx, res;
-	int i;
-	switch (n->type) {
+    int i;
+    switch (n->type) {
         case NODE4:
             for (i=0; i < n->num_children; i++) {
                 res = recursive_iter(((art_node4*)n)->children[i], cb, data);
@@ -941,12 +941,6 @@ int art_iter_prefix(art_tree *t, const unsigned char *key, int key_len, art_call
     art_node *n = t->root;
     int prefix_len, depth = 0;
     while (n) {
-
-        if (IS_LEAF(n)) {
-            n = (art_node*)LEAF_RAW(n);
-            art_leaf *l = (art_leaf*)n;
-			printf("LEAF: %s\n", l->key);
-		} 
         // Might be a leaf
         if (IS_LEAF(n)) {
             n = (art_node*)LEAF_RAW(n);
@@ -998,7 +992,7 @@ int art_iter_prefix(art_tree *t, const unsigned char *key, int key_len, art_call
 
 static int str_prefix_matches(const art_leaf *n, const unsigned char *str, int str_len) {
     // Fail if the key length is too short
-	if (n->key_len > (uint32_t)str_len) return 1;
+    if (n->key_len > (uint32_t)str_len) return 1;
 
     // Compare the keys
     return memcmp(str, n->key, n->key_len);
@@ -1008,33 +1002,40 @@ void *art_substring(const art_tree *t, const unsigned char *str, int str_len)
 {
     art_node **child;
     art_node *n = t->root;
-	art_leaf *found = NULL;
+    art_node *m;    
+    art_leaf *found = NULL;
+    int prefix_len, depth = 0;
 
-	int prefix_len, depth = 0;
     while (n) {
         // Might be a leaf
         if (IS_LEAF(n)) {
             n = (art_node*)LEAF_RAW(n);
             // Check if the expanded path matches
             if (!str_prefix_matches((art_leaf*)n, str, str_len)) {
-				found = (art_leaf*)n;
+                found = (art_leaf*)n;
             }
-			break;
-		}
+            break;
+        }
+
+        // Check if current is leaf
+    	child = find_child(n, 0);
+    	m = (child) ? *child : NULL;
+    	if (m && IS_LEAF(m)) {
+            m = (art_node*)LEAF_RAW(m);
+            // Check if the expanded path matches
+            if (!str_prefix_matches((art_leaf*)m, str, str_len)) {
+                found = (art_leaf*)m;
+            }
+    	}
 
         // Bail if the prefix does not match
         if (n->partial_len) {
             prefix_len = check_prefix(n, str, str_len, depth);
             if (prefix_len != min(MAX_PREFIX_LEN, n->partial_len))
-				break;
-			depth = depth + n->partial_len;
+                break;
+            depth = depth + n->partial_len;
         }
 
-        art_leaf *l = maximum(n);
-        if (!str_prefix_matches(l, str, str_len)) {
-			found = l;
-		}
-
         // Recursively search
         child = find_child(n, str[depth]);
         n = (child) ? *child : NULL;
@@ -1042,8 +1043,8 @@ void *art_substring(const art_tree *t, const unsigned char *str, int str_len)
     }
 
     if (found == NULL) {
-		return NULL;
-	}
+        return NULL;
+    }
 
     return found->value;
-}
\ No newline at end of file
+}