diff --git a/stretch/x86/Dockerfile b/stretch/x86/Dockerfile
index b0bb0060aa91a6b3188299c8c682cb7e22233673..a7738499cb9c61bbf0b1f81466ddbe990a1342d9 100644
--- a/stretch/x86/Dockerfile
+++ b/stretch/x86/Dockerfile
@@ -14,7 +14,7 @@ RUN groupadd -g 1000 jenkins \
  && echo 'Defaults:jenkins !requiretty' | tee -a /etc/sudoers \
  && echo 'jenkins ALL=(ALL:ALL) NOPASSWD: ALL' | tee -a /etc/sudoers
 
-RUN echo "deb http://ftp.debian.org/debian stretch-backports main" >/etc/apt/sources.list.d/backports.list
+RUN echo "deb http://deb.debian.org/debian stretch-backports main" >/etc/apt/sources.list.d/backports.list
 
 RUN curl https://packages.icinga.com/icinga.key | apt-key add - \
  && DIST=$(awk -F"[)(]+" '/VERSION=/ {print $2}' /etc/os-release) \
diff --git a/stretch/x86_64/Dockerfile b/stretch/x86_64/Dockerfile
index c8a568ff221eaffa055d3db7314f69ca9dcf21b1..041e661c0b0c50b7f6dc4b2503726bd24b4b5eca 100644
--- a/stretch/x86_64/Dockerfile
+++ b/stretch/x86_64/Dockerfile
@@ -14,7 +14,7 @@ RUN groupadd -g 1000 jenkins \
  && echo 'Defaults:jenkins !requiretty' | tee -a /etc/sudoers \
  && echo 'jenkins ALL=(ALL:ALL) NOPASSWD: ALL' | tee -a /etc/sudoers
 
-RUN echo "deb http://ftp.debian.org/debian stretch-backports main" >/etc/apt/sources.list.d/backports.list
+RUN echo "deb http://deb.debian.org/debian stretch-backports main" >/etc/apt/sources.list.d/backports.list
 
 RUN curl https://packages.icinga.com/icinga.key | apt-key add - \
  && DIST=$(awk -F"[)(]+" '/VERSION=/ {print $2}' /etc/os-release) \