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Table Of Contents  The TCP/IP Guide
 9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  TCP/IP Key Applications and Application Protocols
           9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)
                9  Usenet (Network News) and the TCP/IP Network News Transfer Protocol (NNTP)
                     9  TCP/IP Network News Transfer Protocol (NNTP)

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NNTP Command Extensions
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TCP/IP World Wide Web (WWW, "The Web") and the Hypertext Transfer Protocol (HTTP)
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NNTP Status Responses and Response Codes
(Page 2 of 3)

Reply Code Structure and Digit Interpretation

As with SMTP and FTP, NNTP reply codes can be considered to be of the form “xyz”, where “x” is the first digit, “y” the second and “z” the third.

First Reply Code Digit (“x”)

The first digit indicates the success, failure or progress of the command in general terms, whether a successful command is complete or incomplete, and the general reason why an unsuccessful command did not work. The values of this digit are defined slightly differently than in SMTP and FTP. In some cases, the terminology is just simplified; for example, the second category is “Command OK” instead of “Positive Completion Reply”. Table 270 shows the specific meaning of the possible values of this digit.

Table 270: NNTP Reply Code Format: First Digit Interpretation

Reply Code Format




Informative Message

General information; used for help information and debugging.


Command OK

The command was completed successfully.


Command OK So Far, Send The Rest

An intermediate reply, sent to prompt the client to send more information. Typically used for replies to commands such as IHAVE or POST, where the server acknowledges the command and then requests that an article be transmitted by the client.


Command Was Correct, But Couldn't Be Performed

The command was valid but could not be performed. This type of error usually occurs due to bad parameters, a transient problem with the server, bad command sequence or similar situations.


Command Unimplemented Or Incorrect, Or Serious Program Error

The command was invalid or a significant program error prevented it from being performed.

Second Reply Code Digit (“y”)

The second digit categorizes messages into functional groups. This digit is used in the same general way as in SMTP and FTP, but the functional groups are different; they are described in Table 271.

Table 271: NNTP Reply Code Format: Second Digit Interpretation

Reply Code Format




Connection, Setup and Miscellaneous

Generic and miscellaneous replies.


Newsgroup Selection

Messages related to commands used to select a newsgroup.


Article Selection

Messages related to commands used to select an article.


Distribution Functions

Messages related to the transfer of messages.



Messages related to posting messages.



Messages related to authentication and the AUTHINFO command extension. (This category is not officially listed in the standard, but these responses have a middle digit of “5”).


Nonstandard Extensions

Reserved for private, non-standard implementation use.



Debugging output messages.

Third Reply Code Digit (“z”)

This last digit indicates a specific type of message within each of the functional groups described by the second digit. The third digit allows each functional group to have 10 different reply codes for each reply type given by the first code digit.

Combining Digit Values to Make Specific Reply Codes

As in FTP and SMTP, these “x”, “y” and “z” digit meanings are combined to make specific reply codes. For example, the reply code “435” is sent by the server if a client issues the IHAVE command but the server doesn't want the article being offered. The command was correct but the reply is negative, thus it starts with “4”, and the message is related to message distribution, so the middle digit is “3”.

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Version 3.0 - Version Date: September 20, 2005

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