RFC Errata
RFC 2308, "Negative Caching of DNS Queries (DNS NCACHE)", March 1998
Note: This RFC has been updated by RFC 4035, RFC 4033, RFC 4034, RFC 6604, RFC 8020, RFC 8499, RFC 9499, RFC 9520
Source of RFC: dnsind (int)See Also: RFC 2308 w/ inline errata
Errata ID: 461
Status: Verified
Type: Editorial
Publication Format(s) : TEXT
Reported By: Hideshi Enokihara
Date Reported: 2006-02-01
Verifier Name: Brian Haberman
Date Verified: 2012-05-01
Section 7.2 says:
7.2 Dead / Unreachable Server (OPTIONAL) Dead / Unreachable servers are servers that fail to respond in any way to a query or where the transport layer has provided an indication that the server does not exist or is unreachable. A server may be deemed to be dead or unreachable if it has not responded to an outstanding query within 120 seconds. Examples of transport layer indications are: ICMP error messages indicating host, net or port unreachable. TCP resets IP stack error messages providing similar indications to those above. A server MAY cache a dead server indication. If it does so it MUST NOT be deemed dead for longer than five (5) minutes. The indication MUST be stored against query tuple <query name, type, class, server IP address> unless there was a transport layer indication that the server does not exist, in which case it applies to all queries to that specific IP address.
It should say:
7.2 Dead / Unreachable Server (OPTIONAL) Dead / Unreachable servers are servers that fail to respond in any way to a query or where the transport layer has provided an indication that the server does not exist or is unreachable. A server may be deemed to be dead or unreachable if it has not responded to an outstanding query within 120 seconds. Examples of transport layer indications are: ICMP error messages indicating host, net or port unreachable. TCP resets IP stack error messages providing similar indications to those above. A resolver MAY cache a dead server indication. If it does so it MUST NOT be deemed dead for longer than five (5) minutes. The indication MUST be stored against query tuple <query name, type, class, server IP address> unless there was a transport layer indication that the server does not exist, in which case it applies to all queries to that specific IP address.
Notes:
Last sentence says, "A server MAY cache a dead server indication.".
But, this "server" is typo, I think.
This "server" should be "resolver" because section 7.1's last sentence uses "resolver".