DNS EDE option for rate-limited queries

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Table of Contents

1. Introduction

DNS nameservers return EDNS Extended DNS Errors options [RFC8914] in query responses to provide extra details about the result of DNS query processing. This memo documents EDNS Extended DNS Errors INFO-CODE values to be returned when rate-limiting is performed, or an over-quota condition is reached.¶

2. "Rate Limited" EDE INFO-CODE

When DNS queries or transactions are rate-limited, e.g., due to the effect of DNS Response Rate Limiting [RRL] or client IP-address based rate limiting, nameservers may return RCODE=REFUSED or return truncated responses possibly with an empty answer section depending on the implementation. In such responses, nameservers MAY include an EDNS Extended DNS Error option with the INFO-CODE set to "Rate Limited" as provided in Section 6.¶

3. "Over Quota" EDE INFO-CODE

When DNS queries or transactions cause an over-quota condition such as when the count of DNS UPDATEs allowed for a customer have breached a limit, nameservers may return failures. In such responses, nameservers MAY include an EDNS Extended DNS Error option with the INFO-CODE set to "Over Quota" as provided in Section 6.¶

6. IANA considerations

IANA is requested to allocate the following code point in the "Extended DNS Error Codes" registry in the "Domain Name System (DNS) Parameters" registry group.¶

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