diff --git a/Dockerfile b/Dockerfile
index 65a64557..ea4e6920 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -11,11 +11,11 @@ ENV GITLAB_INSTALL_DIR="${GITLAB_HOME}/gitlab" \
     GITLAB_SHELL_INSTALL_DIR="${GITLAB_HOME}/gitlab-shell" \
     GITLAB_DATA_DIR="${GITLAB_HOME}/data"
 
-RUN apt-key adv --keyserver keyserver.ubuntu.com --recv E1DD270288B4E6030699E45FA1715D88E1DF1F24 \
+RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv E1DD270288B4E6030699E45FA1715D88E1DF1F24 \
  && echo "deb http://ppa.launchpad.net/git-core/ppa/ubuntu trusty main" >> /etc/apt/sources.list \
- && apt-key adv --keyserver keyserver.ubuntu.com --recv 80F70E11F0F0D5F10CB20E62F5DA5F09C3173AA6 \
+ && apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 80F70E11F0F0D5F10CB20E62F5DA5F09C3173AA6 \
  && echo "deb http://ppa.launchpad.net/brightbox/ruby-ng/ubuntu trusty main" >> /etc/apt/sources.list \
- && apt-key adv --keyserver keyserver.ubuntu.com --recv 8B3981E7A6852F782CC4951600A6F0A3C300EE8C \
+ && apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 8B3981E7A6852F782CC4951600A6F0A3C300EE8C \
  && echo "deb http://ppa.launchpad.net/nginx/stable/ubuntu trusty main" >> /etc/apt/sources.list \
  && wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add - \
  && echo 'deb http://apt.postgresql.org/pub/repos/apt/ trusty-pgdg main' > /etc/apt/sources.list.d/pgdg.list \