diff --git a/docker-compose.yml b/docker-compose.yml
index 14d657c..c23155c 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -17,6 +17,7 @@ services:
       GC_REGISTRY_TOKEN: "${GC_REGISTRY_TOKEN:-}"
       GC_MAIL_PUBLIC: "${GC_MAIL_PUBLIC:-1}"
       GC_DNS_AXFR_ALLOW: "${GC_DNS_AXFR_ALLOW:-}"
+      GC_MAIL_HELO: "${GC_MAIL_HELO:-}"
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
       - gc-setup-data:/data