diff --git a/lib/ildus/server/backend.rb b/lib/ildus/server/backend.rb
index 284f727..0fd24d2 100644
--- a/lib/ildus/server/backend.rb
+++ b/lib/ildus/server/backend.rb
@@ -196,6 +196,7 @@ module Ildus
 
         # (*Interface*) Updates the address of the given
         # _host_ to the give address _addr_.
+        # If _addr_ is *nil*, the entry should be removed.
         def update_host(host, addr)
           raise Handler::NotImplementedError
         end
diff --git a/lib/ildus/server/domain_backends/ldap.rb b/lib/ildus/server/domain_backends/ldap.rb
index 5332137..039cd52 100644
--- a/lib/ildus/server/domain_backends/ldap.rb
+++ b/lib/ildus/server/domain_backends/ldap.rb
@@ -59,7 +59,7 @@ module Ildus::Server::DomainBackend
     end # def hosts
 
     # Updates the address of _host_ to _addr_ providing that _addr_ is in a
-    # correct IPv4 or IPv6 address format.
+    # correct IPv4 or IPv6 address format or *nil*.
     def update_host(host, addr)
       entry = all_entries.find do |entry| 
         entry['associatedDomain'][0] == "#{host}.#{config['name']}"
@@ -69,11 +69,19 @@ module Ildus::Server::DomainBackend
       if addr.ipv4?
         record = entry['aRecord']
         return false if record and record[0] == addr.to_s
-        @ldap.modify(entry['dn'][0], {"aRecord"    => [addr.to_s]})
+        if addr.to_i.zero?
+          @ldap.modify(entry['dn'][0], {"aRecord"    => []})
+        else
+          @ldap.modify(entry['dn'][0], {"aRecord"    => [addr.to_s]})
+        end
       elsif addr.ipv6?
         record = entry['aAAARecord']
         return false if record and record[0] == addr.to_s
-        @ldap.modify(entry['dn'][0], {"aAAARecord" => [addr.to_s]})
+        if addr.to_i.zero?
+          @ldap.modify(entry['dn'][0], {"aAAARecord" => []})
+        else
+          @ldap.modify(entry['dn'][0], {"aAAARecord" => [addr.to_s]})
+        end
       else
         return false
       end
diff --git a/lib/ildus/server/handler.rb b/lib/ildus/server/handler.rb
index 67abba3..bef0745 100644
--- a/lib/ildus/server/handler.rb
+++ b/lib/ildus/server/handler.rb
@@ -69,7 +69,7 @@ module Ildus
         @io      = io
         @commit  = false
 
-        # Create the domain backend.
+        # Create the domain name service backend.
         type     = @config["domain"]["type"]
         klass    = Backend.get_domain(type)
         raise "domain backend type `#{type}' not found" if klass.nil?