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Network Working Group                                           J. MyersRequest for Comments: 2087                               Carnegie MellonCategory: Standards Track                                   January 1997IMAP4 QUOTA extensionStatus of this Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.1.   Abstract   The QUOTA extension of the Internet Message Access Protocol [IMAP4]   permits administrative limits on resource usage (quotas) to be   manipulated through the IMAP protocol.Table of Contents1.   Abstract...........................................12.   Conventions Used in this Document..................13.   Introduction and Overview..........................24.   Commands...........................................24.1. SETQUOTA Command...................................24.2. GETQUOTA Command...................................24.3. GETQUOTAROOT Command...............................35.   Responses..........................................35.1. QUOTA Response.....................................35.2. QUOTAROOT Response.................................46.   Formal syntax......................................47.   References.........................................58.   Security Considerations............................59.   Author's Address...................................52.   Conventions Used in this Document   In examples, "C:" and "S:" indicate lines sent by the client and   server respectively.Myers                       Standards Track                     [Page 1]

RFC 2087                         QUOTA                      January 19973.   Introduction and Overview   The QUOTA extension is present in any IMAP4 implementation which   returns "QUOTA" as one of the supported capabilities to the   CAPABILITY command.   An IMAP4 server which supports the QUOTA capability may support   limits on any number of resources.  Each resource has an atom name   and an implementation-defined interpretation which evaluates to an   integer.  Examples of such resources are:      Name       Interpretation      STORAGE    Sum of messages'RFC822.SIZE, in units of 1024 octets      MESSAGE    Number of messages   Each mailbox has zero or more implementation-defined named "quota   roots".  Each quota root has zero or more resource limits.  All   mailboxes that share the same named quota root share the resource   limits of the quota root.   Quota root names do not necessarily have to match the names of   existing mailboxes.4.   Commands4.1. SETQUOTA Command   Arguments:  quota root               list of resource limits   Data:       untagged responses: QUOTA   Result:     OK - setquota completed               NO - setquota error: can't set that data               BAD - command unknown or arguments invalid   The SETQUOTA command takes the name of a mailbox quota root and a   list of resource limits. The resource limits for the named quota root   are changed to be the specified limits.  Any previous resource limits   for the named quota root are discarded.   If the named quota root did not previously exist, an implementation   may optionally create it and change the quota roots for any number of   existing mailboxes in an implementation-defined manner.Myers                       Standards Track                     [Page 2]

RFC 2087                         QUOTA                      January 1997   Example:    C: A001 SETQUOTA "" (STORAGE 512)               S: * QUOTA "" (STORAGE 10 512)               S: A001 OK Setquota completed4.2. GETQUOTA Command   Arguments:  quota root   Data:       untagged responses: QUOTA   Result:     OK - getquota completed               NO - getquota  error:  no  such  quota  root,  permission               denied               BAD - command unknown or arguments invalid   The GETQUOTA command takes the name of a quota root and returns the   quota root's resource usage and limits in an untagged QUOTA response.   Example:    C: A003 GETQUOTA ""               S: * QUOTA "" (STORAGE 10 512)               S: A003 OK Getquota completed4.3. GETQUOTAROOT Command   Arguments:  mailbox name   Data:       untagged responses: QUOTAROOT, QUOTA   Result:     OK - getquota completed               NO - getquota error: no such mailbox, permission denied               BAD - command unknown or arguments invalid   The GETQUOTAROOT command takes the name of a mailbox and returns the   list of quota roots for the mailbox in an untagged QUOTAROOT   response.  For each listed quota root, it also returns the quota   root's resource usage and limits in an untagged QUOTA response.   Example:    C: A003 GETQUOTAROOT INBOX               S: * QUOTAROOT INBOX ""               S: * QUOTA "" (STORAGE 10 512)               S: A003 OK Getquota completedMyers                       Standards Track                     [Page 3]

RFC 2087                         QUOTA                      January 19975.   Responses5.1. QUOTA Response   Data:       quota root name               list of resource names, usages, and limits      This response occurs as a result of a GETQUOTA or GETQUOTAROOT      command. The first string is the name of the quota root for which      this quota applies.      The name is followed by a S-expression format list of the resource      usage and limits of the quota root.  The list contains zero or      more triplets.  Each triplet conatins a resource name, the current      usage of the resource, and the resource limit.      Resources not named in the list are not limited in the quota root.      Thus, an empty list means there are no administrative resource      limits in the quota root.      Example:    S: * QUOTA "" (STORAGE 10 512)5.2. QUOTAROOT Response   Data:       mailbox name               zero or more quota root names      This response occurs as a result of a GETQUOTAROOT command.  The      first string is the mailbox and the remaining strings are the      names of the quota roots for the mailbox.      Example:    S: * QUOTAROOT INBOX ""                  S: * QUOTAROOT comp.mail.mime6.   Formal syntax   The following syntax specification uses the augmented Backus-Naur   Form (BNF) notation as specified inRFC 822 with one exception; the   delimiter used with the "#" construct is a single space (SP) and not   one or more commas.   Except as noted otherwise, all alphabetic characters are case-   insensitive.  The use of upper or lower case characters to define   token strings is for editorial clarity only.  Implementations MUST   accept these strings in a case-insensitive fashion.Myers                       Standards Track                     [Page 4]

RFC 2087                         QUOTA                      January 1997   getquota        ::= "GETQUOTA" SP astring   getquotaroot    ::= "GETQUOTAROOT" SP astring   quota_list      ::= "(" #quota_resource ")"   quota_resource  ::= atom SP number SP number   quota_response  ::= "QUOTA" SP astring SP quota_list   quotaroot_response                   ::= "QUOTAROOT" SP astring *(SP astring)   setquota        ::= "SETQUOTA" SP astring SP setquota_list   setquota_list   ::= "(" 0#setquota_resource ")"   setquota_resource ::= atom SP number7.   References   [IMAP4] Crispin, M., "Internet Message Access Protocol - Version 4",RFC 1730, University of Washington, December 1994.   [RFC-822] Crocker, D., "Standard for    the Format of ARPA Internet   Text Messages", STD 11,RFC 822.8.   Security Considerations   Implementors should be careful to make sure the implementation of   these commands does not violate the site's security policy. The   resource usage of other users is likely to be considered confidential   information and should not be divulged to unauthorized persons.9.   Author's Address   John G. Myers   Carnegie-Mellon University   5000 Forbes Ave.   Pittsburgh PA, 15213-3890   EMail: jgm+@cmu.eduMyers                       Standards Track                     [Page 5]