Symptom
- Smart licensing fails to register with the following error message:
%SMART_LIC-3-COMM_FAILED: Communications failure with the Cisco Smart Software Manager (CSSM) : No detailed information given
- "show license tech support" will show that the reason for communication failure is "NO REPLY"
Communication Statistics:
=======================
Communication Level Allowed: INDIRECT
Overall State:
Trust Establishment:
Attempts: Total=10, Success=0, Fail=10 Ongoing Failure: Overall=10 Communication=10
Last Response: NO REPLY on Sep 11 20:07:51 2023 UTC
- packet capture or DNS debug will reveal that the affected device resolves AAAA record (IPv6), but never tries to resolve A record (IPv4)
Conditions
- Smart transport enabled
- IPv6 is enabled on any interface
- HTTP client source interface is not configured for IPv6
- Device is able to resolve CSSM AAAA (IPv6) DNS record
