diff --git a/lib/resolv.rb b/lib/resolv.rb
index 47c4ef6b3b..0db6cc5c59 100644
--- a/lib/resolv.rb
+++ b/lib/resolv.rb
@@ -2560,11 +2560,7 @@ class Resolv
     attr_reader :address
 
     def to_s # :nodoc:
-      address = sprintf("%x:%x:%x:%x:%x:%x:%x:%x", *@address.unpack("nnnnnnnn"))
-      unless address.sub!(/(^|:)0(:0)+(:|$)/, '::')
-        address.sub!(/(^|:)0(:|$)/, '::')
-      end
-      return address
+      sprintf("%x:%x:%x:%x:%x:%x:%x:%x", *@address.unpack("nnnnnnnn")).sub(/(^|:)0(:0)+(:|$)/, '::')
     end
 
     def inspect # :nodoc:
diff --git a/test/resolv/test_dns.rb b/test/resolv/test_dns.rb
index 9d243bbf50..d9db8408fd 100644
--- a/test/resolv/test_dns.rb
+++ b/test/resolv/test_dns.rb
@@ -374,7 +374,8 @@ class TestResolvDNS < Test::Unit::TestCase
       ["2001:db8::1", "2001:db8::0:1"],
       ["::", "0:0:0:0:0:0:0:0"],
       ["2001::", "2001::0"],
-      ["2001:db8::1:1:1:1:1", "2001:db8:0:1:1:1:1:1"],
+      ["2001:db8:0:1:1:1:1:1", "2001:db8:0:1:1:1:1:1"], # RFC 5952 Section 4.2.2.
+      ["2001:db8::1:1:1:1", "2001:db8:0:0:1:1:1:1"],
       ["1::1:0:0:0:1", "1:0:0:1:0:0:0:1"],
       ["1::1:0:0:1", "1:0:0:0:1:0:0:1"],
     ]