diff --git a/README.md b/README.md
index e8ba7b7..32d102e 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,8 @@ Necessary DNS records :
 
 > Do not make AAAA record for mail.<domain> zones, otherwise your mailserver will not be able to recieve messages from Gmail (and maybe others).
 
+Also set the reverse DNS to `mail.netig.net.`.
+
 Get TLS certificates with Caddy and make them available through volume like this :
 ```
       # mail.netig.net certs