diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 2c63351a..55f6a1be 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -16,6 +16,12 @@ jobs:
      - name: Run shellcheck
        run: ./scripts/build/shellcheck.sh
 
+     - name: Validate Nameserver
+       run: |
+         ping google.com
+         nslookup google.com 8.8.8.8
+         nslookup google.com 1.1.1.1
+
      - name: Setup Python & Poetry Environment
        uses: exasol/python-toolbox/.github/actions/python-environment@0.14.0
        with:
diff --git a/exasol/ds/sandbox/runtime/ansible/roles/jupyter/files/notebook_requirements.txt b/exasol/ds/sandbox/runtime/ansible/roles/jupyter/files/notebook_requirements.txt
index f0ce1637..fa517d3a 100644
--- a/exasol/ds/sandbox/runtime/ansible/roles/jupyter/files/notebook_requirements.txt
+++ b/exasol/ds/sandbox/runtime/ansible/roles/jupyter/files/notebook_requirements.txt
@@ -3,7 +3,7 @@ matplotlib==3.7.4 # required for notebook sklearn
 jupysql==0.10.10 # required for multiple notebooks
 stopwatch.py>=2.0.1 # also required by ITDE
 exasol-notebook-connector==0.3.0
-exasol-integration-test-docker-environment==3.1.0 # experimental
+# exasol-integration-test-docker-environment==3.1.0 # experimental
 pickleshare==0.7.5 # See https://github.com/exasol/ai-lab/issues/291 for details.
 ipyfilechooser==0.6.0 # required for SLC notebooks
 ipywidgets==8.1.1 # enable interactive Javascript widgets in the notebooks