diff --git a/Dockerfile b/Dockerfile
index b7f1746..1875a70 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,8 +4,8 @@ FROM ubuntu:${UBUNTU_VER}
 
 ARG TARGETPLATFORM
 
-ENV TZ Asia/Hong_Kong
-ENV DEBIAN_FRONTEND noninteractive
+ENV TZ=Asia/Hong_Kong
+ENV DEBIAN_FRONTEND=noninteractive
 
 # Enable autocompletion
 RUN rm /etc/apt/apt.conf.d/docker-*
@@ -21,10 +21,12 @@ RUN apt install -y net-tools iputils-ping tcpdump traceroute iproute2 iptables i
 
 RUN apt install -y software-properties-common
 
+RUN apt install -y tzdata
+
 # Installing locales
 RUN apt install -y locales
-ENV LC_ALL en_US.UTF-8
-ENV LANG en_US.UTF-8
+ENV LC_ALL=en_US.UTF-8
+ENV LANG=en_US.UTF-8
 RUN locale-gen en_US.UTF-8
 
 # Allow non-root users to run sudo command without password.
@@ -32,6 +34,9 @@ RUN echo "ALL ALL=NOPASSWD:ALL" > /etc/sudoers.d/01-allow-sudo
 
 COPY scripts/entrypoint.sh /entrypoint.sh
 
-ENV LOG_FILE /dev/null
+ENV LOG_FILE=/dev/null
+
+# Reset DEBIAN_FRONTEND
+ENV DEBIAN_FRONTEND=dialog
 
 CMD [ "/entrypoint.sh" ]