Network & Infrastructure
An application treats every DNS error as a nonexistent service and suppresses retries. A resolver failure or validation problem should not be interpreted as an authoritative statement that the name does not exist.
DNS, DNSSEC & Service Discovery2 นาทีในการอ่าน
อ่านบทความ : SERVFAIL versus NXDOMAIN in outage diagnosis
Network & Infrastructure
A resolver encrypts upstream DNS but accepts an unverified endpoint identity. Encryption alone may not establish that the peer is the intended resolver service.
DNS, DNSSEC & Service Discovery1 นาทีในการอ่าน
อ่านบทความ : DNS over TLS: encrypted transport still needs server identity
Network & Infrastructure
Several unrelated signed domains suddenly fail through one resolver. A bad local clock can invalidate otherwise correct signatures across many zones simultaneously.
DNS, DNSSEC & Service Discovery1 นาทีในการอ่าน
อ่านบทความ : Resolver clock skew and widespread DNSSEC validation failures
Network & Infrastructure
A resolver cluster handles normal load comfortably but saturates after restart or upstream degradation. Warm-cache query rates can substantially understate the work required during a failure.
DNS, DNSSEC & Service Discovery1 นาทีในการอ่าน
อ่านบทความ : Recursive DNS capacity under cold-cache failure conditions
Network & Infrastructure
A redundant edge routes outbound and return packets through different firewall instances. Each path is individually reachable, but connection state is unavailable where later packets arrive.
Segmentation, TLS & Secure Connectivity2 นาทีในการอ่าน
อ่านบทความ : Stateful firewall asymmetry after a routing change
Network & Infrastructure
A newly added application permit receives no hits while traffic continues to be denied or unexpectedly allowed elsewhere. An earlier rule may already determine the decision.
Segmentation, TLS & Secure Connectivity1 นาทีในการอ่าน
อ่านบทความ : Firewall rule shadowing and a permit that never matches
Network & Infrastructure
A firewall rule references the public service address, but the platform evaluates the relevant policy after translation. The expected permit never matches even though NAT counters increase.
Segmentation, TLS & Secure Connectivity2 นาทีในการอ่าน
อ่านบทความ : NAT and security-policy matching at different processing stages
Network & Infrastructure
Applications intermittently fail to open outbound sessions through a shared egress while existing connections remain usable. The translation pool can run out of usable mappings before bandwidth is exhausted.
Segmentation, TLS & Secure Connectivity2 นาทีในการอ่าน
อ่านบทความ : SNAT port exhaustion under high outbound concurrency
Network & Infrastructure
A shared HTTPS endpoint serves the wrong certificate or backend for one hostname. IP reachability and port checks pass because the failure depends on the requested server name.
Segmentation, TLS & Secure Connectivity2 นาทีในการอ่าน
อ่านบทความ : TLS SNI routing and the correct certificate on the wrong backend
Network & Infrastructure
A service works in some browsers but fails on fresh clients or automated agents. Cached intermediates can hide an incomplete chain supplied by the endpoint.
Segmentation, TLS & Secure Connectivity2 นาทีในการอ่าน
อ่านบทความ : Incomplete TLS certificate chains behind a load balancer
Network & Infrastructure
Two workloads successfully authenticate each other with certificates, yet one receives access beyond its intended role. A valid certificate proves an identity under a trust model, not every permission.
Segmentation, TLS & Secure Connectivity2 นาทีในการอ่าน
อ่านบทความ : mTLS identity is not the same as application authorization
Network & Infrastructure
A certificate replacement is published, but resumed connections do not exercise the same handshake path as fresh sessions. Monitoring only resumed traffic can miss an invalid replacement bundle.
Segmentation, TLS & Secure Connectivity2 นาทีในการอ่าน
อ่านบทความ : TLS session resumption and certificate-rotation assumptions