diff --git a/test/resolv/test_dns.rb b/test/resolv/test_dns.rb
index 617babf829..d3c4b1f3e9 100644
--- a/test/resolv/test_dns.rb
+++ b/test/resolv/test_dns.rb
@@ -156,7 +156,7 @@ class TestResolvDNS < Test::Unit::TestCase
             ra =     (flags & 0x0080) >> 7
             z =      (flags & 0x0070) >> 4
             rcode =   flags & 0x000f
-            rest = msg[12..-1]
+            _rest = msg[12..-1]
 
             questions = msg.bytes[12..-1]
             labels = []