integer.

          NO-USER

          The connection specified by the port pair is not
          currently in use or currently not owned by an
          identifiable entity.

          HIDDEN-USER

          The server was able to identify the user of this
          port, but the information was not returned at the
          request of the user.

          UNKNOWN-ERROR

          Can't determine connection owner; reason unknown.
          Any error not covered above should return this
          error code value.  Optionally, this code MAY be
          returned in lieu of any other specific error code
          if, for example, the server desires to hide
          information implied by the return of that error




 
RFC 1413                Identification Protocol            February 1993


          code, or for any other reason.  If a server
          implements such a feature, it MUST be configurable
          and it MUST default to returning the proper error
          message.

   Other values may eventually be specified and defined in future
   revisions to this document.  If an implementer has a need to specify
   a non-standard error code, that code must begin with "X".

   In addition, the server is allowed to drop the query connection
   without responding.  Any premature close (i.e., one where the client
   does not receive the EOL, whether graceful or an abort should be
   considered to have the same meaning as "ERROR : UNKNOWN-ERROR".

FORMAL SYNTAX

    ::=  

    ::=  "," 

    ::=  

    ::= "015 012"  ; CR-LF End of Line Indicator

    ::= <error-reply> | <ident-reply>

   <error-reply> ::=  ":" "ERROR" ":" 

   <ident-reply> ::=  ":" "USERID" ":" <opsys-field>
                     ":" 

    ::= "INVALID-PORT" | "NO-USER" | "UNKNOWN-ERROR"
                    | "HIDDEN-USER" |  <error-token>

   <opsys-field> ::=  [ "," ]

    ::= "OTHER" | "UNIX" |  ...etc.
               ;  (See "Assigned Numbers")

    ::= "US-ASCII" | ...etc.
                 ;  (See "Assigned Numbers")

    ::= <octet-string>

    ::= 1*64<token-characters> ; 1-64 characters

   <error-token> ::= "X"1*63<token-characters>
                     ; 2-64 chars beginning w/X




 
RFC 1413                Identification Protocol            February 1993


    ::= 1*5 ; 1-5 digits.

    ::= "0" | "1" ... "8" | "9" ; 0-9

   <token-characters> ::=
                  <Any of these ASCII characters: a-z, A-Z,
                   - (dash), .!@#$%^&*()_=+.,<>/?"'~`{}[]; >
                               ; upper and lowercase a-z plus
                               ; printables minus the colon ":"
                               ; character.

   <octet-string> ::= 1*512<octet-characters>

   <octet-characters> ::=