diff --git a/customers/8505_lmz/ucs-school-lib/python/models/computer.py b/customers/8505_lmz/ucs-school-lib/python/models/computer.py
index ab7b471..f2728dd 100644
@@ -189,6 +190,13 @@ class SchoolComputer(UCSSchoolHelperAbstractClass):
 		network = self.get_network()
 		if network:
 			udm_obj['network'] = network.dn
+		ipv4_network = self.get_ipv4_network()
+		if ipv4_network:
+			if ipv4_network.ip == ipv4_network.network:
+				# IP is set to network address, replace it
+				self.ip_address = None
+			else:
+				udm_obj['ip'] = str(ipv4_network.ip)
 		# TODO: groups. for memberserver...
 		return super(SchoolComputer, self).do_create(udm_obj, lo)
 
@@ -230,7 +238,8 @@ class SchoolComputer(UCSSchoolHelperAbstractClass):
 
 	def validate(self, lo, validate_unlikely_changes=False):
 		super(SchoolComputer, self).validate(lo, validate_unlikely_changes)
-		if self.ip_address:
+		# don't test existance of IP address if it is the network's address
+		if self.ip_address and self.get_ipv4_network().ip != self.get_ipv4_network().network:
 			name, ip_address = escape_filter_chars(self.name), escape_filter_chars(self.ip_address)
 			if AnyComputer.get_first_udm_obj(lo, '&(!(cn=%s))(ip=%s)' % (name, ip_address)):
 				self.add_error('ip_address', _('The ip address is already taken by another computer. Please change the ip address.'))