I observed that my local Uni gateway config was correct — link to AS1 healthy, campus reachable, firewall open, NAT properly configured — but all external destinations returned ICMP Network Unreachable from 4.2.2.1 (AS1's next hop). I decided to escalate to AS1 after completing the local audit, and ultimately reported CANNOT (pending admin action) to the user. The root cause is architectural: no node in the topology has real Internet transit. AS1 had removed its default route (which caused a routing loop with AS2) and replaced it with a specific route to ACM's network only, so internal destinations like 198.82.0.1 work but nothing else does. External DNS fails as a downstream symptom because AS1's dnsmasq forwards to the unreachable 8.8.8.8. Fixing this requires administrators to procure external transit service — beyond any agent's authority.