diff --git a/modules/mailserver/postfix.nix b/modules/mailserver/postfix.nix
index 23809db..d1aca5d 100644
--- a/modules/mailserver/postfix.nix
+++ b/modules/mailserver/postfix.nix
@@ -95,6 +95,7 @@ lib.mkIf cfg.enable {
       smtpd_tls_protocols = "!SSLv2, !SSLv3, !TLSv1, !TLSv1.1";
       smtpd_tls_mandatory_ciphers = "medium";
       smtpd_tls_loglevel = "1";
+      smtpd_tls_received_header = "yes"; # add TLS connection details to Received header
 
       tls_medium_cipherlist = listToString [
         "ECDHE-ECDSA-AES128-GCM-SHA256"