The following is a list of general response codes that may be sent by the NNTP server. These are not specific to any one command, but may be returned as the result of a connection, a failure, or some unusual condition.
In general, 1xx codes may be ignored or displayed as desired; code 200 or 201 is sent upon initial connection to the NNTP server depending upon posting permission; code 400 will be sent when the NNTP server discontinues service (by operator request, for example); and 5xx codes indicate that the command could not be performed for some unusual reason.
100 help text
190
through
199 debug output
200 server ready - posting allowed
201 server ready - no posting allowed
400 service discontinued
500 command not recognized
501 command syntax error
502 access restriction or permission denied
503 program fault - command not performed