</>
ProtocolCodes
22
DNS

22 BADTRUNC

Bad truncation. The TSIG record was truncated in a way that makes it impossible to verify the message signature.

On this page

When You See This Code

A large DNS response was truncated (TC bit set) but the TSIG MAC was computed over the full message, making the truncated version unverifiable.

How to Fix

Retry the query over TCP to avoid truncation. If using UDP, ensure your EDNS buffer size is large enough to receive the full signed response.

Specification

View RFC / Specification →

Compare With

0 NOERROR 1 FORMERR 2 SERVFAIL 3 NXDOMAIN 4 NOTIMP 5 REFUSED 6 YXDOMAIN 7 YXRRSET 8 NXRRSET 9 NOTAUTH 10 NOTZONE 11 DSOTYPENI

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

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 22 BADTRUNC?

Bad truncation. The TSIG record was truncated in a way that makes it impossible to verify the message signature.

When do you see DNS 22 BADTRUNC?

A large DNS response was truncated (TC bit set) but the TSIG MAC was computed over the full message, making the truncated version unverifiable.

How to fix DNS 22 BADTRUNC?

Retry the query over TCP to avoid truncation. If using UDP, ensure your EDNS buffer size is large enough to receive the full signed response.