diff --git a/lib/utils.js b/lib/utils.js
index ee57b40f..f6128633 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -16,10 +16,15 @@ utils.aton6 = function(a) {
 	}
 
 	if (l < 7) {
-		a.length = 8;
-
-		for (i = l; i >= 0 && a[i] !== ''; i--) {
-			a[7-l+i] = a[i];
+		const omitted = 8 - a.length
+		const omitStart = a.indexOf('')
+		const omitEnd = omitStart + 8 - a.length
+
+		for (let i = 7; i >= omitStart; i--) {
+			if (i > omitEnd)
+				a[i] = a[i - omitted]
+			else
+				a[i] = 0
 		}
 	}
 
@@ -95,4 +100,4 @@ utils.ntoa6 = function(n) {
 	a = a.replace(/:$/, ']').replace(/:0+/g, ':').replace(/::+/, '::');
 
 	return a;
-};
\ No newline at end of file
+};