diff --git a/reverse_expand_ipv4.js b/reverse_expand_ipv4.js
new file mode 100644
index 0000000..3c8477a
--- /dev/null
+++ b/reverse_expand_ipv4.js
@@ -0,0 +1,3 @@
+function Rev4(str){
+    return srt.split(".").reverse().join(".") + ".in-addr.arpa"
+}
diff --git a/reverse_expand_ipv6.js b/reverse_expand_ipv6.js
new file mode 100644
index 0000000..302ea30
--- /dev/null
+++ b/reverse_expand_ipv6.js
@@ -0,0 +1,24 @@
+function RevRev6(str) {
+    let arr = str.split(":");
+    let filler;
+    for (let i = 0; i < arr.length; i++) {
+        if (arr[i] == "") {
+                if (filler) {
+                    arr[i] = "0000";
+                } else {
+                    filler = i;
+                }
+            } else {
+            while (arr[i].length < 4) {
+                arr[i] = "0" + arr[i];
+            }
+        }
+    }
+    if (filler) {
+        arr.splice(filler, 1, "0000");
+        while (arr.length < 8) {
+            arr.splice(filler, 0, "0000");
+        }
+    }
+    return arr.join("").split("").reverse().join(".") + ".ipv6.arpa"
+}