Suricata

Lychee is a good tool for this, I just ran it over the generated HTML in the userguide:

[./configuration/suricata-yaml.html]:
✗ [500] https://www.ran-lifshitz.com/2014/08/28/symmetric-rss-receive-side-scaling/ | Failed: Network error: Internal Server Error

[./rules/enip-keyword.html]:
✗ [ERR] http://read.pudn.com/downloads166/ebook/763211/EIP-CIP-V1-1.0.pdf | Failed: Network error: dns error: no record found for Query { name: Name("read.pudn.com.unx.ca."), query_type: AAAA, query_class: IN }

[./rules/modbus-keyword.html]:
✗ [404] http://www.ssi.gouv.fr/agence/publication/detection-dintrusion-dans-les-systemes-industriels-suricata-et-le-cas-modbus/ | Failed: Network error: Not Found

[./public-data-sets.html]:
✗ [404] https://stratosphereips.org/category/dataset.html | Failed: Network error: Not Found

[./capture-hardware/myricom.html]:
✗ [ERR] http://www.40gbe.net/index_files/be59da7f2ab5bf0a299ab99ef441bb2e-28.html | Failed: Network error: dns error: no record found for Query { name: Name("www.40gbe.net.unx.ca."), query_type: AAAA, query_class: IN }
✗ [404] https://www.broadcom.com/support/knowledgebase/1211161394432/how-to-use-emulex-oneconnect-oce12000-d-adapters-with-faststack | Failed: Network error: Not Found

[./performance/hyperscan.html]:
✗ [403] https://www.intel.com/content/www/us/en/developer/articles/technical/introduction-to-hyperscan.html | Failed: Network error: Forbidden