diff --git a/services/univention-samba4/lib/base.sh b/services/univention-samba4/lib/base.sh
index 4a890ecfb9..4b75e832ca 100644
--- a/services/univention-samba4/lib/base.sh
+++ b/services/univention-samba4/lib/base.sh
@@ -204,9 +204,9 @@ get_available_s4connector_dc() {
 				## this can either be the administration or the education section,
 				## both have separate samba domains, so ignore the other section
 				if is_localhost_education; then
-					s4cldapfilter="(&(univentionService=S4 Connector)(objectClass=univentionDomainController)(!(univentionService=UCS@school Administration)))"
+					s4cldapfilter="(&(univentionService=S4 SlavePDC)(univentionService=S4 Connector)(objectClass=univentionDomainController)(univentionService=UCS@school Education))"
 				elif is_localhost_administration; then
-					s4cldapfilter="(&(univentionService=S4 Connector)(objectClass=univentionDomainController)(!(univentionService=UCS@school Education)))"
+					s4cldapfilter="(&(univentionService=S4 SlavePDC)(univentionService=S4 Connector)(objectClass=univentionDomainController)(univentionService=UCS@school Administration))"
 				else
 					echo "ERROR: This seems to be a UCS@school school department server," 1>&2
 					echo "ERROR: but is neither a administrative nor a educative server." 1>&2