5
DNS
5 REFUSED
Query refused. The name server refuses to perform the requested operation for policy reasons.
Cuándo verás este código
The server rejected your query due to access control — for example, a recursive resolver that only serves its own network, or a zone transfer blocked by ACL.
Cómo solucionarlo
Check the server's allow-query, allow-recursion, or allow-transfer ACLs. If you are not authorized to use this resolver, switch to a public DNS service.
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Guías
HTTP Request Lifecycle: From URL to Response
HTTP Fundamentals
Step-by-Step DNS Troubleshooting with dig and nslookup
Debugging & Troubleshooting
Improving Email Deliverability: SPF, DKIM, and DMARC Setup
Email Delivery
DNS Response Codes (RCODEs) Explained
DNS & Networking
DNS TTL: How to Set TTL Values and Avoid Propagation Delays
DNS & Networking
DNS Propagation: Why Changes Take Time
DNS & Networking
DNSSEC Implementation Guide
DNS & Networking
DNS-Based Failover and High Availability
DNS & Networking
DNS Record Types Explained: A, AAAA, CNAME, MX, TXT, and Beyond
DNS & Networking
DNS over HTTPS (DoH) and DNS over TLS (DoT): Encrypted DNS Explained
DNS & Networking
Essential Network Debugging Tools: ping, traceroute, mtr, and tcpdump
DNS & Networking
Resource Hints: Preload, Prefetch, Preconnect, and DNS-Prefetch
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RFC 9114: HTTP/3 Protocol Deep Dive
Protocol Deep Dives
RFC 3261: SIP Protocol Deep Dive
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QUIC Protocol: The Transport Layer Behind HTTP/3
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Migrating from TLS 1.2 to TLS 1.3: Configuration and Compatibility
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