diff --git a/lib/net/ldap.rb b/lib/net/ldap.rb
index 54f0da2..dc24b83 100644
--- a/lib/net/ldap.rb
+++ b/lib/net/ldap.rb
@@ -273,6 +273,9 @@ module Net
 
     AsnSyntax = BER.compile_syntax({
       :application => {
+	:primitive => {
+	  2 => :null		    # UnbindRequest body
+        },
         :constructed => {
           0 => :array,              # BindRequest
           1 => :array,              # BindResponse