diff --git a/.gitignore b/.gitignore
index 9ac76d8fac..66e1db0246 100644
--- a/.gitignore
+++ b/.gitignore
@@ -77,3 +77,4 @@
 target/
 src/
 .gclient_entries
+.gclient_previous_sync_commits
diff --git a/Makefile b/Makefile
index 70e88127ad..1e3a147cab 100644
--- a/Makefile
+++ b/Makefile
@@ -20,13 +20,13 @@ gn_flags := --args='is_debug=false'
 all: init sync app release
 
 init:
-	docker build dockers --build-arg UID=$(shell id -u) --build-arg GUID=$(shell id -g) -f $(build_dockerfile) -t $(compile_docker)
+	docker build dockers --network host --build-arg UID=$(shell id -u) --build-arg GUID=$(shell id -g) -f $(build_dockerfile) -t $(compile_docker)
 
 release:
 	docker build $(target_dir) -f $(release_dockerfile) -t $(release_docker)
 
 sync:
-	docker run $(docker_flags) $(compile_docker) \
+	docker run --network host $(docker_flags) $(compile_docker) \
 		make docker-$@ \
 		output_dir=$(output_dir) \
 		gn_flags=$(gn_flags)
@@ -34,7 +34,7 @@ sync:
 app: peerconnection_serverless
 
 peerconnection_serverless:
-	docker run $(docker_flags) $(compile_docker) \
+	docker run --network host $(docker_flags) $(compile_docker) \
 		make docker-$@ \
 		output_dir=$(output_dir) \
 		target_lib_dir=$(target_lib_dir) \
diff --git a/README.md b/README.md
index 9529ed53f7..a2c519353b 100644
--- a/README.md
+++ b/README.md
@@ -84,12 +84,22 @@ To compile AlphaRTC, please refer to the following steps
 
 3. Build Docker images
 
-   ``` shell
-   cd AlphaRTC
-   make all
-   ```
-
-   You should then be able to see two Docker images, `alphartc` and `alphartc-compile` using `sudo docker images`
+    1. Change line 18, 19 of `AlphaRTC/dockers/Dockerfile.compile` to [your own proxy port](https://github.com/alanhg/others-note/issues/503)
+
+        ```Dockerfile
+        # in `AlphaRTC/dockers/Dockerfile.compile`
+        ENV HTTP_PROXY "http://127.0.0.1:<your_proxy_port>"
+        ENV HTTPS_PROXY "http://127.0.0.1:<your_proxy_port>"
+        ```
+
+    2. Compile AlphaRTC (about 10min+)
+   
+        ``` shell
+        cd AlphaRTC
+        make all
+        ```
+
+    You should then be able to see two Docker images, `alphartc` and `alphartc-compile` using `sudo docker images`
 
 ### Option 2: Compile from Scratch
 If you don't want to use Docker, or have other reasons to compile from scratch (e.g., you want a native Windows build), you may use this method.
diff --git a/dockers/Dockerfile.compile b/dockers/Dockerfile.compile
index e207f3339c..3ce7c4a39a 100644
--- a/dockers/Dockerfile.compile
+++ b/dockers/Dockerfile.compile
@@ -15,6 +15,10 @@ RUN useradd ${USER} -l -u ${UID} -g ${GUID} -m -s /bin/bash || true
 ARG DEPOT_TOOLS=/opt/depot_tools
 ARG DOCKER_WORKDIR=/app/AlphaRTC/
 
+ENV HTTP_PROXY "http://127.0.0.1:15777"
+ENV HTTPS_PROXY "http://127.0.0.1:15777"
+
+RUN apt install ninja-build
 RUN git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git ${DEPOT_TOOLS}
 RUN chown ${USER} -R ${DEPOT_TOOLS}
 ENV PATH="${DEPOT_TOOLS}/:${PATH}"