diff --git a/src/dns.c b/src/dns.c
index 61dac71..88ed1ad 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -1346,7 +1346,7 @@ int _dns_encode_opts(struct dns_packet *packet, struct dns_context *context, str
 		payloadsize = DNS_DEFAULT_PACKET_SIZE;
 	}
 
-	ret = _dns_encode_rr_head(context, "0", DNS_T_OPT, payloadsize, rcode, rr_len);
+	ret = _dns_encode_rr_head(context, "", DNS_T_OPT, payloadsize, rcode, rr_len);
 	if (ret < 0) {
 		return -1;
 	}
diff --git a/src/dns.h b/src/dns.h
index f06d739..436cfff 100644
--- a/src/dns.h
+++ b/src/dns.h
@@ -10,8 +10,8 @@
 #define DNS_RR_AAAA_LEN 16
 #define DNS_MAX_CNAME_LEN 256
 #define DNS_MAX_OPT_LEN 256
-#define DNS_IN_PACKSIZE (512 * 2)
-#define DNS_PACKSIZE (512 * 8)
+#define DNS_IN_PACKSIZE (512 * 4)
+#define DNS_PACKSIZE (512 * 10)
 #define DNS_DEFAULT_PACKET_SIZE 512
 
 #define DNS_ADDR_FAMILY_IP 1
diff --git a/src/dns_conf.c b/src/dns_conf.c
index 622d10e..207ded0 100644
--- a/src/dns_conf.c
+++ b/src/dns_conf.c
@@ -88,8 +88,8 @@ int config_server(int argc, char *argv[], dns_server_type_t type, int default_po
 	}
 
 	if (index >= DNS_MAX_SERVERS) {
-		tlog(TLOG_ERROR, "exceeds max server number");
-		return -1;
+		tlog(TLOG_WARN, "exceeds max server number, %s", ip);
+		return 0;
 	}
 
 	server = &dns_conf_servers[index];
diff --git a/src/dns_conf.h b/src/dns_conf.h
index 0b404ef..740d9d2 100644
--- a/src/dns_conf.h
+++ b/src/dns_conf.h
@@ -10,7 +10,7 @@
 #include "list.h"
 #include "radix.h"
 
-#define DNS_MAX_SERVERS 32
+#define DNS_MAX_SERVERS 64
 #define DNS_MAX_IPSET_NAMELEN 32
 #define DNS_MAX_IPLEN 64
 #define DNS_MAX_PATH 1024
diff --git a/src/dns_server.c b/src/dns_server.c
index 14cdf03..84afb0c 100644
--- a/src/dns_server.c
+++ b/src/dns_server.c
@@ -51,6 +51,10 @@
 #define DNS_MAX_EVENTS 256
 #define DNS_SERVER_TMOUT_TTL (3 * 60)
 #define DNS_CONN_BUFF_SIZE 4096
+#define DNS_REQUEST_MAX_TIMEOUT 1000
+#define DNS_PING_TIMEOUT (DNS_REQUEST_MAX_TIMEOUT - 50)
+#define DNS_TCPPING_START (300)
+#define DNS_PING_TCP_TIMEOUT (DNS_REQUEST_MAX_TIMEOUT - DNS_TCPPING_START - 50)
 
 struct dns_conn_buf {
 	char buf[DNS_CONN_BUFF_SIZE];
@@ -662,15 +666,15 @@ void _dns_server_ping_result(struct ping_host_struct *ping_host, const char *hos
 		may_complete = 1;
 	}
 
-	if (may_complete) {
+	if (may_complete && request->has_ping_result == 1) {
 		_dns_server_request_complete(request);
 		_dns_server_request_remove(request);
 	}
 }
 
-int _dns_server_ping(struct dns_request *request, char *ip)
+int _dns_server_ping(struct dns_request *request, char *ip, int timeout)
 {
-	if (fast_ping_start(ip, 1, 0, 1000, _dns_server_ping_result, request) == NULL) {
+	if (fast_ping_start(ip, 1, 0, timeout, _dns_server_ping_result, request) == NULL) {
 		return -1;
 	}
 
@@ -849,7 +853,7 @@ static int _dns_server_process_answer(struct dns_request *request, char *domain,
 				request->rcode = packet->head.rcode;
 				sprintf(ip, "%d.%d.%d.%d", addr[0], addr[1], addr[2], addr[3]);
 
-				if (_dns_server_ping(request, ip) != 0) {
+				if (_dns_server_ping(request, ip, DNS_PING_TIMEOUT) != 0) {
 					_dns_server_request_release(request);
 				}
 			} break;
@@ -895,7 +899,7 @@ static int _dns_server_process_answer(struct dns_request *request, char *domain,
 				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) {
+				if (_dns_server_ping(request, ip, DNS_PING_TIMEOUT) != 0) {
 					_dns_server_request_release(request);
 				}
 			} break;
@@ -1642,7 +1646,7 @@ void _dns_server_tcp_ping_check(struct dns_request *request)
 		case DNS_T_A: {
 			_dns_server_request_get(request);
 			sprintf(ip, "%d.%d.%d.%d:80", addr_map->ipv4_addr[0], addr_map->ipv4_addr[1], addr_map->ipv4_addr[2], addr_map->ipv4_addr[3]);
-			if (_dns_server_ping(request, ip) != 0) {
+			if (_dns_server_ping(request, ip, DNS_PING_TCP_TIMEOUT) != 0) {
 				_dns_server_request_release(request);
 			}
 		} break;
@@ -1653,7 +1657,7 @@ void _dns_server_tcp_ping_check(struct dns_request *request)
 					addr_map->ipv6_addr[7], addr_map->ipv6_addr[8], addr_map->ipv6_addr[9], addr_map->ipv6_addr[10], addr_map->ipv6_addr[11],
 					addr_map->ipv6_addr[12], addr_map->ipv6_addr[13], addr_map->ipv6_addr[14], addr_map->ipv6_addr[15]);
 
-			if (_dns_server_ping(request, ip) != 0) {
+			if (_dns_server_ping(request, ip, DNS_PING_TCP_TIMEOUT) != 0) {
 				_dns_server_request_release(request);
 			}
 		} break;
@@ -1726,7 +1730,7 @@ void _dns_server_period_run(void)
 	pthread_mutex_lock(&server.request_list_lock);
 	list_for_each_entry_safe(request, tmp, &server.request_list, list)
 	{
-		if (request->send_tick < now - 500 && request->has_ping_tcp == 0) {
+		if (request->send_tick < now - DNS_TCPPING_START && request->has_ping_tcp == 0) {
 			_dns_server_request_get(request);
 			list_add_tail(&request->check_list, &check_list);
 		}