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ProtocolCodes
1
DNS

1 FORMERR

Format error. The name server was unable to interpret the query due to a malformed DNS message.

On this page

When You See This Code

Your DNS client or library sent a query the server could not parse, often caused by a buggy resolver, corrupted packet, or unsupported EDNS options.

How to Fix

Check your DNS client or library version for known bugs. Capture the raw query with dig or Wireshark and verify it conforms to the DNS wire format.

Specification

View RFC / Specification →

Compare With

0 NOERROR 2 SERVFAIL 3 NXDOMAIN 4 NOTIMP 5 REFUSED 6 YXDOMAIN 7 YXRRSET 8 NXRRSET 9 NOTAUTH 10 NOTZONE 11 DSOTYPENI 16 BADVERS/BADSIG

Guides

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 Performance & Optimization
RFC 9114: HTTP/3 Protocol Deep Dive Protocol Deep Dives
RFC 3261: SIP Protocol Deep Dive Protocol Deep Dives
QUIC Protocol: The Transport Layer Behind HTTP/3 Protocol Deep Dives
Migrating from TLS 1.2 to TLS 1.3: Configuration and Compatibility Migration & Upgrades
Secret Management for API Keys, Tokens, and Certificates Production Infrastructure

Specifications

RFC 1035 Domain Names - Implementation and Specification

Decision Guides

Why Is DNS Resolution Failing?

Glossary

TCP/IP Port Number Latency Timeout Firewall DNS over HTTPS (DoH) IPv6 Subnet (Subnetwork) MTU (Maximum Transmission Unit) UDP (User Datagram Protocol) DNS Lookup CDN (Content Delivery Network) Request-Response Model RFC (Request for Comments) IANA (Internet Assigned Numbers Authority) Wire Format Extension Mechanism Connectionless Text vs Binary Protocol DNS Resolution DNS Record Types TTL (Time to Live) DNSSEC (DNS Security Extensions) DNS over TLS (DoT) Anycast Recursive Resolver Authoritative Name Server Glue Record EDNS(0) DNS Zone DNS Propagation CNAME Record MX Record SRV Record PTR Record DNS Cache Poisoning DNS Root Server Split-Horizon DNS Wildcard DNS Record SPF, DKIM, and DMARC Email Deliverability MTA (Mail Transfer Agent) ARC (Authenticated Received Chain) BIMI (Brand Indicators for Message Identification) Service Discovery GSLB (Global Server Load Balancing) Failover Active-Passive HA

Frequently Asked Questions

What is DNS 1 FORMERR?

Format error. The name server was unable to interpret the query due to a malformed DNS message.

When do you see DNS 1 FORMERR?

Your DNS client or library sent a query the server could not parse, often caused by a buggy resolver, corrupted packet, or unsupported EDNS options.

How to fix DNS 1 FORMERR?

Check your DNS client or library version for known bugs. Capture the raw query with dig or Wireshark and verify it conforms to the DNS wire format.