diff --git a/MailServerInstall.md b/MailServerInstall.md
index b628adf..5217ddf 100644
--- a/MailServerInstall.md
+++ b/MailServerInstall.md
@@ -4,3 +4,8 @@
 ```console 
 root@serveur:~# apt-get install postfix-mysql 
 ```
+### Check if master.cf 
+```console 
+root@serveur:~# vim /etc/postfix/master.cf
+```
+