diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6c41991a8745df13ec99683d37a6539b3888d72e..5ff189f7c70444a9f568e59a9feff1d594f6be28 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,7 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed ###
 
 * Set PyYAML dependency back to PyYaml>=5.4.1 (from 6.0) for better
-  compatibility with docker-compose)
+  compatibility with docker-compose
+* Use Debian mirrors at Netcup for pipeline tests.
 
 ### Deprecated ###
 
diff --git a/unittests/docker/Dockerfile b/unittests/docker/Dockerfile
index 7fa3f75bd198724628dee48ab328829fa071a639..06f9d6c830068a2c1c85caef79c64f899eaefb33 100644
--- a/unittests/docker/Dockerfile
+++ b/unittests/docker/Dockerfile
@@ -1,4 +1,8 @@
 FROM debian:latest
+# Use local package repository
+COPY sources.list.local /etc/apt/
+RUN mv /etc/apt/sources.list /etc/apt/sources.list.orig
+RUN cat /etc/apt/sources.list.local /etc/apt/sources.list.orig > /etc/apt/sources.list
 RUN apt-get update && \
     apt-get install -y \
       pylint3 python3-pip tox git \
diff --git a/unittests/docker/sources.list.local b/unittests/docker/sources.list.local
new file mode 100644
index 0000000000000000000000000000000000000000..c0b4107350ba37e77aa95d5a56c31976979e51e1
--- /dev/null
+++ b/unittests/docker/sources.list.local
@@ -0,0 +1,6 @@
+# Local repositories at Netcup
+deb http://debian.netcup.net/debian/ buster main
+deb http://mirrors.n-ix.net/debian-security buster/updates main
+deb http://debian.netcup.net/debian/ buster-updates main
+
+# The original content follows here:
\ No newline at end of file