diff --git a/lib/net.js b/lib/net.js
index 4e76dfac06c7e8..a9bb212120e326 100644
--- a/lib/net.js
+++ b/lib/net.js
@@ -985,7 +985,7 @@ function lookupAndConnect(self, options) {
     dnsopts.hints = dns.ADDRCONFIG;
   }
 
-  debug('connect: find host ' + host);
+  debug('connect: find host', host);
   debug('connect: dns options', dnsopts);
   self._host = host;
   var lookup = options.lookup || dns.lookup;
@@ -1160,7 +1160,7 @@ function createServerHandle(address, port, addressType, fd) {
       handle = createHandle(fd);
     } catch (e) {
       // Not a fd we can listen on.  This will trigger an error.
-      debug('listen invalid fd=' + fd + ': ' + e.message);
+      debug('listen invalid fd=%d:', fd, e.message);
       return uv.UV_EINVAL;
     }
     handle.open(fd);
@@ -1181,7 +1181,7 @@ function createServerHandle(address, port, addressType, fd) {
   }
 
   if (address || port || isTCP) {
-    debug('bind to ' + (address || 'anycast'));
+    debug('bind to', address || 'any');
     if (!address) {
       // Try binding to ipv6 first
       err = handle.bind6('::', port);