diff --git a/binding/c/test_util b/binding/c/test_util
index bc93a29..6f2c779 100755
Binary files a/binding/c/test_util and b/binding/c/test_util differ
diff --git a/binding/c/xdb_api.h b/binding/c/xdb_api.h
index 21e28d3..af846cc 100644
--- a/binding/c/xdb_api.h
+++ b/binding/c/xdb_api.h
@@ -34,9 +34,19 @@
 #define xdb_vector_index_size  8
 #define xdb_segment_index_size 14
 
+// --- ip version info
+#define xdb_ipv4_version_no 4
+#define xdb_ipv6_version_no 6
+#define XDB_IPV4 4
+#define XDB_IPv6 6
+
 // cache of vector_index_row × vector_index_rows × vector_index_size
 #define xdb_vector_index_length 524288
 
+// types type define
+typedef char string_ip_t;
+typedef unsigned char bytes_ip_t;
+
 // --- xdb util functions
 
 // get the current time in microseconds
@@ -55,15 +65,32 @@ XDB_PUBLIC(int) xdb_check_ip(const char *, unsigned int *);
 XDB_PUBLIC(void) xdb_long2ip(unsigned int, char *);
 
 
-// parse the specified IP address to byte array
-XDB_PUBLIC(int) xdb_parse_ip(const char *, const char *, size_t);
+// parse the specified IP address to byte array.
+// returns: 4 for valid ipv4, 16 for valid ipv6, or -1 for failed
+XDB_PUBLIC(int) xdb_parse_ip(const string_ip_t *, bytes_ip_t *, size_t);
 
-// convert a specified ip bytes to humen-readable string
-XDB_PUBLIC(int) xdb_ip_to_string(const char *, size_t);
+// parse the specified IPv4 address to byte array
+// returns: 4 for valid ipv4, or -1 for failed
+XDB_PUBLIC(int) xdb_parse_v4_ip(const string_ip_t *, bytes_ip_t *, size_t);
+
+// parse the specified IPv6 address to byte array
+// returns: 16 for valid ipv6, or -1 for failed
+XDB_PUBLIC(int) xdb_parse_v6_ip(const string_ip_t *, bytes_ip_t *, size_t);
+
+// convert a specified ip bytes to humen-readable string.
+// returns: 0 for success or -1 for failed.
+XDB_PUBLIC(int) xdb_ip_to_string(const bytes_ip_t *, size_t, char *, size_t);
+
+// ipv4 bytes to string
+XDB_PUBLIC(int) xdb_v4_ip_to_string(const bytes_ip_t *, char *, size_t);
+
+// ipv6 bytes to string
+XDB_PUBLIC(int) xdb_v6_ip_to_string(const bytes_ip_t *, char *, size_t);
 
 // compare the specified ip bytes with another ip bytes in the specified buff from offset.
+// ip args must be the return value from #xdb_parse_ip.
 // returns: -1 if ip1 < ip2, 1 if ip1 > ip2 or 0
-XDB_PUBLIC(int) xdb_ip_sub_compare(const char *, const char *, int, size_t);
+XDB_PUBLIC(int) xdb_ip_sub_compare(const bytes_ip_t *, size_t, const char *, int);
 
 // --- END xdb utils
 
diff --git a/binding/c/xdb_util.c b/binding/c/xdb_util.c
index 2c0f034..812f7b4 100644
--- a/binding/c/xdb_util.c
+++ b/binding/c/xdb_util.c
@@ -96,15 +96,73 @@ XDB_PUBLIC(void) xdb_long2ip(unsigned int ip, char *buffer) {
     sprintf(buffer, "%d.%d.%d.%d", (ip >> 24) & 0xFF, (ip >> 16) & 0xFF, (ip >> 8) & 0xFF, ip & 0xFF);
 }
 
-XDB_PUBLIC(int) xdb_parse_ip(const char *ip, const char *buffer, size_t length) {
+XDB_PUBLIC(int) xdb_parse_ip(const string_ip_t *ip, bytes_ip_t *buffer, size_t length) {
+    // where there is a . there is a IPV4 even though there are IPv6 wrapped IPv4 like
+    // ::ffff:192.168.1.100, lets just keep it in this way.
+    if (strchr(ip, '.') != NULL) {
+        return xdb_parse_v4_ip(ip, buffer, length);
+    } else if (strchr(ip, ':') != NULL) {
+        return xdb_parse_v6_ip(ip, buffer, length);
+    }
+
+    return -1;
+}
+
+XDB_PUBLIC(int) xdb_parse_v4_ip(const string_ip_t *ip, bytes_ip_t *buffer, size_t length) {
     return 0;
 }
 
-XDB_PUBLIC(int) xdb_ip_to_string(const char *bytes, size_t length) {
+XDB_PUBLIC(int) xdb_parse_v6_ip(const string_ip_t *ip, bytes_ip_t *buffer, size_t length) {
     return 0;
 }
 
-XDB_PUBLIC(int) xdb_ip_sub_compare(const char *ip1, const char *buffer, int offset, size_t length) {
+XDB_PUBLIC(int) xdb_ip_to_string(const bytes_ip_t *ip, size_t bytes, char *buffer, size_t length) {
+    if (bytes == 4) {
+        return xdb_v4_ip_to_string(ip, buffer, length);
+    } else if (bytes == 16) {
+        return xdb_v6_ip_to_string(ip, buffer, length);
+    }
+
+    return -1;
+}
+
+XDB_PUBLIC(int) xdb_v4_ip_to_string(const bytes_ip_t *ip, char *buffer, size_t length) {
+    snprintf(
+        buffer, length, 
+        "%d.%d.%d.%d", 
+        ip[0], ip[1], ip[2], ip[3]
+    );
+    return 0;
+}
+
+XDB_PUBLIC(int) xdb_v6_ip_to_string(const bytes_ip_t *ip, char *buffer, size_t length) {
+    // temp solution for testing ONLY, we will handle the :: later
+    snprintf(
+        buffer, length,
+        "%x%x:%x%x:%x%x:%x%x:%x%x:%x%x:%x%x:%x%x",
+        ip[0],  ip[1],
+        ip[2],  ip[3],
+        ip[4],  ip[5],
+        ip[6],  ip[7],
+        ip[8],  ip[9],
+        ip[10], ip[11],
+        ip[12], ip[13],
+        ip[14], ip[15]
+    );
+    return 0;
+}
+
+XDB_PUBLIC(int) xdb_ip_sub_compare(const bytes_ip_t *ip1, size_t length, const char *buffer, int offset) {
+    int i, i1, i2;
+    for (i = 0; i < length; i++) {
+        i1 = ip1[i] & 0xFF;
+        i2 = buffer[offset + i] & 0xFF;
+        if (i1 > i2) {
+            return 1;
+        } else if (i1 < i2) {
+            return -1;
+        }
+    }
     return 0;
 }