Exposes architectural fragility
Networking consultant Yvette Schmitter, CEO of the Fusion Collective consulting firm, said the Cloudflare change “exposed Cisco’s architectural fragility when [some Cisco] switches worldwide entered fatal reboot loops every 10-30 minutes.”
What happened? “Cloudflare changed record ordering. Cisco’s firmware, instead of handling unexpected DNS responses gracefully, treated it as fatal and crashed with core dumps. Neither vendor’s testing caught this basic interoperability failure,” Schmitter said. “Cisco has privately acknowledged the issue to customers, but as of January 9 has released no public advisory, no patch, no field notice, leaving enterprises implementing workarounds that disable DNS functionality on network infrastructure.”
Another analyst who was concerned about the nature of the incident is Sanchit Vir Gogia, chief analyst at Greyhound Research.
“What Cloudflare has described is a change in behavior rather than a loss of service. That change was valid from a standards point of view, but it collided with expectations inside certain DNS client implementations. It is possible that a dependency can be alive, reachable, and technically correct, and still cause systems downstream to fail,” Gogia said.
“Most enterprise resilience planning still assumes that things either work or they do not,” he added. “DNS is expected to be up or down, slow or fast. This incident sat in a far less comfortable middle ground. DNS was reachable and fast, yet responses surfaced brittle assumptions inside embedded clients. Traditional monitoring tools are not built to catch that early. Health checks stay green while systems degrade.”
An infrastructure reliability issue
Analysts said that the impact for enterprise customers would have been obvious, even though the cause, initially, was not.
