The Isode Mobile Email Gateway enables mail clients to access Internet Standard POP (Post Office Protocol) mailboxes using IMAP (Internet Message Access Protocol). The gateway is based on M-Box, Isode's IMAP and POP message store.

The back-end of the gateway accesses one or more POP servers, the front end of the gateway is identical to that that of M-Box and provides an IMAP (and POP) interface. Messages are stored by theg ateway to optimize access performance for an IMAP client. Operation is as follows:

  1. When the IMAP Client connects, the back-end of the M-Box POP/IMAP Gateway connects to the POP server and downloads a copy of all messages (messages are left on the POP server and are deleted only if the client deletes the message on the M-Box POP/IMAP gateway. Both servers remain in sync)
  2. M-Box POP/IMAP Gateway is now in a position to provide IMAP access to those messages from IMAP capable clients.
  3. While the IMAP connection remains open, the M-Box POP/IMAP Gateway back-end will poll the POP server (at configurable intervals) to retrieve new messages.
  4. The M-Box POP/IMAP Gateway can notify the IMAP client when new email messages arrive using the IMAP IDLE command.
  5. Continued synchronisation between the POP/IMAP Gateway and the backend POP servers means that messages marked for deletion 'on the server' are deleted from both the POP/IMAP Gateway and the backend POP server.

Internet Mail Conformance


RFC 1123 Requirements for Internet hosts - application and support, R. Braden, October 1989
RFC 2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies, N. Freed, N. Borenstein, November 1996
RFC 2046 Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types, N. Freed, N. Borenstein, November 1996
RFC 2047 (Multipurpose Internet Mail Extensions) MIME Part Three: Header Extensions for Non-ASCII Text, K. Moore, November 1996
RFC 2049 (Multipurpose Internet Mail Extensions) MIME Part Five: Conformance Criteria and Examples, N. Freed, N. Borenstein, November 1996
RFC 3462 The Multipart/Report Content Type for the Reporting of Mail System Administrative Messages, G. Vaudreuil, January 2003


RFC 3501 Internet Message Access Protocol - Version 4rev1, M. Crispen, March 2003
RFC 2088 IMAP4 non-synchronizing literals, J. Myers, January 1997
RFC 2342 IMAP4 Namespace, M. Gahrns & C. Newman, May 1998
RFC 4315 INTERNET MESSAGE ACCESS PROTOCOL - UIDPLUS extension, M Crispen, December 2005
RFC 3691 Internet Message Access Protocol (IMAP) UNSELECT command, A. Melnikov, February 2004
RFC 2177 IMAP4 IDLE command, B. Leiba, June 1997
RFC 4731 IMAP4 extension to SEARCH command for controlling what kind of information is returned, A. Melnikov, D. Cridland, November 2006
RFC 4978 The IMAP COMPRESS Extension, Arnt Gulbandsen, August 2007
RFC 4959 The IMAP Extension for SASL Initial Client Response, Robert Siemborski, A. Gulbrandsen Sept 2007
RFC 4467

Internet Message Access Protocol (IMAP) - URLAUTH extension, M. Crispin, May 2006

RFC 4469

Internet Message Access Protocol (IMAP) - CATENATE extension, P. Resnick, April 2006

RFC 4551 IMAP Extenstion for Conditional STORE Operation of Quick Flag Changes Resyncronization, A. Melnikov, S.Hole, June 2006
RFC 4314

IMAP4 ACL extension, A. Melnikov, December 2005

RFC 2087

IMAP4 QUOTA extension, J. Myers, January 1997


Internet Message Access Protocol - Sort and Thread Extensions, M. Crispin, K. Muchison, November 2006
RFC 5032 WITHIN Search extensions to the IMAP Protocol, Eric Burger, September 2007
RFC 4550 Internet Email to Support Diverse Service Environments (Lemonade) Profile, S. Meas, A. Melnikov, June 2006


IMAP4 LIST Command extensions, B. Leiba, A. Melnikov, September 2006




IMAP4 Extensions for Quick Mailbox Resynchronization, A. Melnikov, D. Cridland, C. Wilson, June 2007


RFC 2033 Local Mail Transfer Protocol, J. Meyers, October 1996
RFC 3848 ESMTP and LMTP Transmission Types Registration, C. Newman, July 2004
RFC 2920 SMTP Service Extension for Command Pipelining, N. Freed, September 2000
RFC 2034 SMTP Service Extension for Returning Enhanced Error Codes, N Freed, October1996
RFC 6152 SMTP Service Extension for 8-bit MIME transport, J. Klensin, N. Freed, M. Rose, E. Stefferud, D. Crocker, March 2011


RFC 3028

Sieve: A Mail Filtering Language, T. Showalter, January 2001

RFC 3431

Sieve Extension: Relational Tests, W. Segmuller, December 2002
RFC 3598 Sieve Email Filtering -- Subaddress Extension, K. Murchison, September 2003
RFC 3894 Sieve Extension: Copying Without Side Effects, J. Degener, October 2004


Sieve Email Filtering: Vacation Extension, T. Showalter, N. Freed, February 2006


A Protocol for Remotely Managing Sieve Scripts, T. Martin, A. Melnikov, February 2006


RFC 1939 Post Office Protocol - Version 3, J. Myers, M. Rose, May 1996
RFC 2449 POP3 Extension Mechanism, R. Gellens, C. Newman, L. Lundblade, November 1998
RFC 1734 POP3 AUTHentication command, J. Myers, December 1994
RFC 2595 Using TLS with IMAP, POP3 and ACAP, C. Newman, June 1999


M-Box is available on Linux, Solaris and Windows. Details on supported platforms and versions can be found here.