diff --git a/lib/resolve.js b/lib/resolve.js
index 83a4328..d384048 100644
--- a/lib/resolve.js
+++ b/lib/resolve.js
@@ -47,9 +47,9 @@ resolve.resolveLinks = function (string, sanitize = escape) {
     }
   }
 
-  const external = (match, href, protocol, rest) =>
+  const external = (match, href, rest) =>
     stash(
-      `<a class="external" target="_blank" href="${href}" title="${href}" rel="nofollow">${escape(rest)} <img src="/images/external-link-ltr-icon.png"></a>`,
+      `<a class="external" target="_blank" href="${href}" title="${href}" rel="noopener">${escape(rest)} <img src="/images/external-link-ltr-icon.png"></a>`,
     )
 
   // markup conversion happens in four phases:
@@ -61,6 +61,6 @@ resolve.resolveLinks = function (string, sanitize = escape) {
   string = (string || '')
     .replace(/〖(\d+)〗/g, '〖 $1 〗')
     .replace(/\[\[([^\]]+)\]\]/gi, internal)
-    .replace(/\[((http|https|ftp):.*?) (.*?)\]/gi, external)
+    .replace(/\[((?:(?:https?|ftp):|\/).*?) (.*?)\]/gi, external)
   return sanitize(string).replace(/〖(\d+)〗/g, unstash)
 }