diff --git a/linkcheck/dns/resolver.py b/linkcheck/dns/resolver.py
index c3169037..cd16ca15 100644
--- a/linkcheck/dns/resolver.py
+++ b/linkcheck/dns/resolver.py
@@ -22,6 +22,7 @@
 import socket
 import sets
 import sys
+import os
 import time
 
 import linkcheck.dns.exception