diff --git a/applications/gitlab.nix b/applications/gitlab.nix
index 3342607..adc4dd8 100644
--- a/applications/gitlab.nix
+++ b/applications/gitlab.nix
@@ -115,6 +115,11 @@ in {
         r_type = "A";
         value = cfg.host.ip;
       }
+      {
+        record = cfg.host.ip;
+        r_type = "PTR";
+        value = "${cfg.domain.sub}.${cfg.domain.base}.${cfg.domain.tld}.";
+      }
     ];
 
     networking.firewall.allowedTCPPorts = [
@@ -140,6 +145,9 @@ in {
       };
     };
 
+    # set a valid HELO address
+    services.postfix.hostname = lib.mkForce "${cfg.domain.sub}.${cfg.domain.base}.${cfg.domain.tld}";
+
     services.gitlab = {
       enable = true;