diff --git a/utils/docker/Dockerfile b/utils/docker/Dockerfile
index 25d5337..214510e 100755
--- a/utils/docker/Dockerfile
+++ b/utils/docker/Dockerfile
@@ -41,7 +41,8 @@
 RUN curl -fsSL https://get.docker.com/gpg | apt-key add -
 RUN curl -fsSL https://get.docker.com/ | sh
 
-RUN pip install -U urllib3 setuptools pyparsing docker python-iptables
+RUN pip install -U urllib3==1.21.1
+RUN pip install -U setuptools pyparsing docker python-iptables
 WORKDIR /
 RUN git clone https://github.com/containernet/containernet.git
 RUN containernet/util/install.sh