diff --git a/container/service/slapd/assets/templates/config.ldif.tmpl b/container/service/slapd/assets/templates/config.ldif.tmpl
index 362d7e1..58f262e 100644
--- a/container/service/slapd/assets/templates/config.ldif.tmpl
+++ b/container/service/slapd/assets/templates/config.ldif.tmpl
@@ -70,6 +70,7 @@ olcRootPW: {{LDAP_ADMIN_PASSWORD}}
 olcDbIndex: objectClass eq
 olcDbIndex: cn eq
 olcDbIndex: member eq
+olcDbIndex: pseudonym eq
 structuralObjectClass: olcMdbConfig
 
 dn: olcDatabase={2}monitor,cn=config