diff --git a/app/models/a.rb b/app/models/a.rb
index f81eac8..b5e678d 100644
--- a/app/models/a.rb
+++ b/app/models/a.rb
@@ -17,7 +17,11 @@ class A < Record
   attr_accessor :host_domain
   validates :host_domain, :inclusion => {:in => Settings.host_domains}, :allow_blank => true
 
-  validates :name, :length => {:minimum => 4}, :if => :host?
+  validates :name,
+    :length => {:minimum => 4},
+    :uniqueness => {:scope => [:domain_id, :type]},
+    :if => :host?
+  
   validate do
     if host? && Settings.protected_hostnames.any? {|hn| name =~ /^#{hn}/i}
       errors[:name] << "cannot be used, please try another"
diff --git a/spec/models/record_spec.rb b/spec/models/record_spec.rb
index 0f0ce60..2e7a8b1 100644
--- a/spec/models/record_spec.rb
+++ b/spec/models/record_spec.rb
@@ -48,4 +48,10 @@ describe Record do
     query.to_sql.should == expected.gsub("\n", '').gsub(/\s+/, ' ').strip
   end
   
+  it "validates host a records dubles" do
+    host_a_record
+    host_a_record2 = build(:a, name: host_a_record.name, content: '127.0.0.2', domain: host_domain, user: user2)
+    host_a_record2.should have(1).errors_on(:name)
+  end
+  
 end