diff --git a/Dockerfile b/Dockerfile
index 8a076e6..ee823b5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -23,7 +23,7 @@ RUN apk --no-cache add \
 
 # set environment variables
 ENV TZ=Etc/UTC
-ENV LOCAL_HOSTNAME=${HOSTNAME}
+ENV LOCAL_HOSTNAME=""
 ENV LOCAL_DOMAINNAME=""
 ENV LOCAL_ENCRYPTION=false
 ENV SMARTHOST=""
diff --git a/entrypoint.sh b/entrypoint.sh
index 2365949..59405dc 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -33,7 +33,7 @@ else
 
     # set failsafes
     [ -z "$SMARTHOST_PORT" ] && SMARTHOST_PORT=587
-    [ -z "$LOCAL_HOSTNAME" ] && LOCAL_HOSTNAME="smarthost"
+    [ -z "$LOCAL_HOSTNAME" ] && LOCAL_HOSTNAME="$(uname -n)"
     [ -z "$LOCAL_DOMAINNAME" ] && LOCAL_DOMAINNAME="${LOCAL_HOSTNAME#*.}"
 
     printf "done\n"