diff --git a/.env.example b/.env.example
index 040bd6ed..28ce3e0e 100644
--- a/.env.example
+++ b/.env.example
@@ -36,6 +36,10 @@ EMAIL_SERVERS_WITH_PRIORITY=[(10, "email.hostname.")]
 # this option doesn't make sense in self-hosted. Set this variable to disable this option.
 # DISABLE_ALIAS_SUFFIX=1
 
+# If you want to use another MTA to send email, you could set the address of your MTA here
+# By default, emails are sent using the the same Postfix server that receives emails
+# POSTFIX_SERVER=my-postfix.com
+
 # the DKIM private key used to compute DKIM-Signature
 DKIM_PRIVATE_KEY_PATH=local_data/dkim.key