What is the value space of HTTP status codes?

[mnot@…]

p1 defines HTTP status codes as "a 3-digit integer result code" with the following value space:

The first digit of the Status-Code defines the class of response. The last two digits do not have any categorization role. There are 5 values for the first digit:

• 1xx: Informational - Request received, continuing process
• 2xx: Success - The action was successfully received, understood, and accepted
• 3xx: Redirection - Further action must be taken in order to complete the request
• 4xx: Client Error - The request contains bad syntax or cannot be fulfilled
• 5xx: Server Error - The server failed to fulfill an apparently valid request

The BNF, however, allows other values;

Status-Code = 3DIGIT

IANA has asked what the status of codes is outside of this range; e.g., is a 0xx status code reserved, unregistered, or just not allowed? Likewise for 6xx (used by some implementations for local status codes) and upwards.

Also, should the value space be defined in p1 or p2?

[julian.reschke@…]

From [982]:

initial version of content-disposition ID derived from draft-reschke-rfc2183-in-http-03 (see #213)

[mnot@…]

p2-semantics now says:

New HTTP status codes are required to fall under one of the categories defined in Section 8.

As per #229.

I think this makes it clear that codes outside those ranges are disallowed (at least for registration purposes).

[julian.reschke@…]

(the change actually happened in [1035])