diff --git a/Dockerfile b/Dockerfile
index e59c3d3..16bcac9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,6 +10,7 @@ RUN apk update --no-cache && \
     postfix && \
     mkdir -p /var/log/supervisor/ /var/run/supervisor/ && \
     sed -i -e 's/inet_interfaces = localhost/inet_interfaces = all/g' /etc/postfix/main.cf && \
+    sed -i -e 's/inet_protocols = all/inet_protocols = ipv4/g' /etc/postfix/main.cf && \
     chmod +x /run.sh && \
     newaliases