diff --git a/lib/net/ldap/dn.rb b/lib/net/ldap/dn.rb
index e314b80e..da0ff7ca 100644
--- a/lib/net/ldap/dn.rb
+++ b/lib/net/ldap/dn.rb
@@ -57,19 +57,19 @@ def each_pair
           state = :key_oid
           key << char
         when ' ' then state = :key
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
       when :key_normal then
         case char
         when '=' then state = :value
         when 'a'..'z', 'A'..'Z', '0'..'9', '-', ' ' then key << char
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
       when :key_oid then
         case char
         when '=' then state = :value
         when '0'..'9', '.', ' ' then key << char
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
       when :value then
         case char
@@ -110,7 +110,7 @@ def each_pair
         when '0'..'9', 'a'..'f', 'A'..'F' then
           state = :value_normal
           value << "#{hex_buffer}#{char}".to_i(16).chr
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
       when :value_quoted then
         case char
@@ -132,7 +132,7 @@ def each_pair
         when '0'..'9', 'a'..'f', 'A'..'F' then
           state = :value_quoted
           value << "#{hex_buffer}#{char}".to_i(16).chr
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
       when :value_hexstring then
         case char
@@ -145,14 +145,14 @@ def each_pair
           yield key.string.strip, value.string.rstrip
           key = StringIO.new
           value = StringIO.new;
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
       when :value_hexstring_hex then
         case char
         when '0'..'9', 'a'..'f', 'A'..'F' then
           state = :value_hexstring
           value << char
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
       when :value_end then
         case char
@@ -162,14 +162,14 @@ def each_pair
           yield key.string.strip, value.string.rstrip
           key = StringIO.new
           value = StringIO.new;
-        else raise "DN badly formed"
+        else raise Net::LDAP::InvalidDNError, "DN badly formed"
         end
-      else raise "Fell out of state machine"
+      else raise Net::LDAP::InvalidDNError, "Fell out of state machine"
       end
     end
 
     # Last pair
-    raise "DN badly formed" unless
+    raise Net::LDAP::InvalidDNError, "DN badly formed" unless
       [:value, :value_normal, :value_hexstring, :value_end].include? state
 
     yield key.string.strip, value.string.rstrip
diff --git a/lib/net/ldap/error.rb b/lib/net/ldap/error.rb
index 50442d06..2fe61fa6 100644
--- a/lib/net/ldap/error.rb
+++ b/lib/net/ldap/error.rb
@@ -60,6 +60,7 @@ class SearchScopeInvalidError < Error; end
   class ResponseTypeInvalidError < Error; end
   class ResponseMissingOrInvalidError < Error; end
   class EmptyDNError < Error; end
+  class InvalidDNError < Error; end
   class HashTypeUnsupportedError < Error; end
   class OperatorError < Error; end
   class SubstringFilterError < Error; end
diff --git a/test/test_dn.rb b/test/test_dn.rb
index a7b269b0..ac5949a8 100644
--- a/test/test_dn.rb
+++ b/test/test_dn.rb
@@ -26,7 +26,6 @@ def test_to_a_hash_symbol
     assert_equal ['1.23.4', '#A3B4D5', 'ou', 'Company'], dn.to_a
   end
 
-  # TODO: raise a more specific exception than RuntimeError
   def test_bad_input_raises_error
     [
       'cn=James,',
@@ -38,7 +37,7 @@ def test_bad_input_raises_error
       'd1.2=Value',
     ].each do |input|
       dn = Net::LDAP::DN.new(input)
-      assert_raises(RuntimeError) { dn.to_a }
+      assert_raises(Net::LDAP::InvalidDNError) { dn.to_a }
     end
   end
 end