diff --git a/samba/templates/domain.conf-bdc.erb b/samba/templates/domain.conf-bdc.erb
index ebca096..eee4969 100644
--- a/samba/templates/domain.conf-bdc.erb
+++ b/samba/templates/domain.conf-bdc.erb
@@ -1,6 +1,8 @@
 
 os level = 130
 
+max protocol = NT1
+
 domain master = no
 domain logons = yes
 time server = yes
diff --git a/samba/templates/domain.conf-pdc.erb b/samba/templates/domain.conf-pdc.erb
index 4ad801b..e5a054b 100644
--- a/samba/templates/domain.conf-pdc.erb
+++ b/samba/templates/domain.conf-pdc.erb
@@ -1,6 +1,8 @@
 
 os level = 140
 
+max protocol = NT1
+
 domain master = yes
 preferred master = yes
 domain logons = yes