--- a/examples/compressors_comparison.py
+++ b/examples/compressors_comparison.py
@@ -25,6 +25,10 @@
 
 import pandas as pd
 
+if int(os.getenv('DEBIAN_POLICY_SECTION_4_9_NO_NETWORK_ACCESS', '0')) > 0:
+    raise IOError('Debian Policy Section 4.9 prohibits network access during build')
+
+
 url = ("https://archive.ics.uci.edu/ml/machine-learning-databases/"
        "kddcup99-mld/kddcup.data.gz")
 names = ("duration, protocol_type, service, flag, src_bytes, "
