Inspect CoreDNS config and logs troubleshooting
Review Corefile (forward/cache) and tail logs for SERVFAIL/upstream errors
kubectl -n kube-system get cm coredns -o yaml; kubectl -n kube-system logs deploy/coredns --tail=50
more troubleshooting
all 32 commands →
TLS cipher and protocol enum
nmap --script ssl-enum-ciphers -p 443 <host>
Verify full TLS chain and SNI
openssl s_client -connect <host>:443 -servername <host> -showcerts 2>/dev/null | grep -E 'Verify|s:|i:'
Batch cert expiry scan
for h in $(cat hosts.txt); do echo -n "$h "; echo | openssl s_client -connect $h:443 -servername $h 2>/dev/null | openssl x509 -noout -enddate; done
Decode JWT claims
cut -d. -f2 <<<"$JWT" | tr '_-' '/+' | base64 -d 2>/dev/null | jq .
List gRPC services via reflection
grpcurl -plaintext <host>:<port> list; grpcurl -plaintext <host>:<port> describe <svc>