/* ========================================================================
* Copyright 1988-2007 University of Washington
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
*
* ========================================================================
*/
KNOWN BUGS/MISFEATURES/DEFICIENCIES IN THE IMAP TOOLKIT
Last Updated: 15 November 2007
The following are known problems/deficiencies in the imap-2007 toolkit:
. Possible problems for some installations:
. In some versions of Redhat Linux, SVR4-style timezone name lookup
doesn't work properly due to a bug in glibc. The workaround is to
edit os_lnx.c to include tz_bsd.c instead of tz_sv4.c. Note that
other versions of Linux don't support BSD-style timezone name
lookup, so don't make this change unless it's needed on your system.
. In some systems, the OpenSSL distribution is installed other than at
the standard /usr/local/ssl location. If this is the case on your
system and you want to build with SSL support, you will need to set
the SSLDIR variable, either by including a setting of EXTRASPECIALS
in the make command line, e.g.
build lnp SPECIALAUTHENTICATORS=ssl EXTRASPECIALS="SSLDIR=/usr/ssl"
or by editing .../src/osdep/unix/Makefile
. /tmp, /usr/tmp or /var/tmp (if present), and the mail spool directory
must be protected 1777 (world write with sticky bit); otherwise
mailbox locking and updates won't work. An alternative to 1777 on
the mail spool directory is to install the mlock program that is
bundled with the IMAP toolkit.
. Multiple access protection locking does not work if the mailbox or
/tmp are NFS mounted.
. Shared access mailbox formats (mbx, mtx, mx, and tenex) do not work
well with NFS and such usage is not supported. mmdf and unix formats
are supported for use over NFS; however there won't be any multiple
access locking protection.
. Server startup delays may occur if a reverse DNS (IP address to name)
lookup on the client's IP address does not complete in an expeditious
fashion. This is actually a DNS problem and should be fixed in the
DNS and/or the server's host table. A workaround exists (see the
top-level Makefile for details) but is not recommended and can not
be used at all with Kerberos.
. At the insistance of the security gurus, SSL certification validation
is now on by default. This means that you must now use the new
/novalidate-cert switch if establishing an SSL connection to a server
with a self-signed certificate; i.e. if "imap.example.com" has a
self-signed certificate, you must use a mailbox name such as
{imap.example.com/ssl/novalidate-cert}INBOX
to get an SSL session instead of just
{imap.example.com/ssl}INBOX
. GCC 8.x and above on SGI systems does not correctly pass/return
structures which are smaller than 16 bytes and are not 8 bytes. The
problem is that structures are padded at the wrong end; e.g. a 4 byte
structure is loaded into the lower 4 bytes of the register when it
should be loaded into the upper 4 bytes of the register. This affects
IRIX 6 the most because it is a 64-bit system and 4 byte structures are
common. This compiler bug impacts the use of inet_ntoa() in c-client
and causes syslog messages to show IP addresses as 255.255.255.255
instead of the correct values. The fix is either to use SGI's C compiler
instead of GCC or link with an implementation of inet_ntoa() that was
built with GCC instead of the standard SGI C library version.
. By default, the UNIX SSL build assumes that RSAREF is not needed, because
RSA Security Inc. released the RSA public key encryption algorithm into
the public domain on September 6, 2000. There is no longer any need to
use RSAREF, and since RSAREF is slower than OpenSSL's RSA routines
there's good reason not to. If for some reason you still want to use
RSAREF, you will need to edit .../src/osdep/unix/Makefile to
change SSLRSA to load libRSAglue and librsaref.
. By default, the UNIX SSL build assumes that no name conflict exists
between OpenSSL and Kerberos 5. If you are using an older version
of Kerberos, you may need to edit .../src/osdep/unix/Makefile
to change SSLCRYPTO so that it loads the OpenSSL libcrypto library
explicitly as libcrypto.a.
. By default, host names are canonicalized via gethostbyname() and
gethostbyaddr() for everything except for SSL certificate validation.
This can represent a security bug due to DNS spoofing, but is more
likely to deliver results that users expect and also may be necessary
to get Kerberos to work. Set variable "trustdns" in mail.c to NIL if
you want to disable this.
. Bugs:
. It doesn't work to have a "}" character as a user name in /user= in a
mailbox name, even if the user name is quoted. In other words,
{example.com/user="foo}bar"}zap
won't work; foo will be interpreted as an unterminated quoted string
and the remote mailbox name will be
bar"}zap.
. The experimental mx driver has performance problems and shouldn't be used
. docs/internal.txt is out of date (again)
. UIDPLUS bugs/limitations:
. Not supported in all local file formats (see below).
. There are two known issues with UIDPLUS in the mmdf and unix formats:
(a) If the destination mailbox is currently selected (whether in this
or another session), no COPYUID or APPENDUID is returned. The other
choice was to assign a UID based upon the uid_last value and hope
that the session selecting the mailbox would pick it up and update
uid_last. The problem was a timing race if another message was
copied/appended to that mailbox before the selecting session updated
the mailbox. If the timing race is lost, then all UID in the mailbox
would be reassigned by the selecting session, thus making the
returned APPENDUID/COPYUID data useless and causing a performance
problem.
Earlier versions did the "hope for the best" method. This was
revoked in favor of not returning COPYUID/APPENDUID.
Although this violates RFC 4315, there is a loophole which, although
for other purposes, permits this behavior.
(b) There is a known failure if the destination mailbox is currently
selected by legacy software (e.g. older versions of the IMAP
server, Pine, etc.). In this case, all UIDs end up being
reassigned by the legacy software.
. Annoyances:
. Friendly host names (e.g. "server" instead of "server.foo.com") can't be
used in a mailbox name with SSL certificate validation; you have to enter
the fully-qualified domain name. This is a requirement established by
the security gurus.
. IMAP client limitations:
. No SASL protection mechanisms (SASL authentication mechanisms are
supported)
. NNTP client limitations:
. Non-standard IMAP SCAN extension not supported
. POP client limitations:
. No SASL protection mechanisms (SASL authentication mechanisms are
supported)
. No POP3 UID support
. Non-standard IMAP SCAN extension not supported
. SMTP client limitations:
. No SASL protection mechanisms (SASL authentication mechanisms are
supported)
. No support for use of TURN, ETRN, and pipelining.
. No support for enhanced status codes
. UNIX limitations:
. IPv6 is supported but is not the default on most platforms; you have to
use IP=6 in the make command
. Supported local file formats: mbx, mh, mmdf, mix, mtx, mx, news, phile,
tenex, unix
. Supported SASL mechanisms: CRAM-MD5, PLAIN, LOGIN, ANONYMOUS, GSSAPI
. Sticky UIDs are not supported in the mh, mtx, and tenex drivers
. Creation of keywords is not supported in the mh, mtx, and tenex drivers
. Copy and append of keywords only works in the mbx driver.
. Flat file formats (mbx, mmdf, mtx, phile, tenex, unix) do not permit
mailboxes to have inferior names
. SSL temporary key should be seeded better than it is.
. UIDPLUS support is limited to the unix, mmdf, mbx, mx, and mix formats.
. Non-standard IMAP SCAN extension not support for mh and news formats.
. Amiga limitations:
. Supported local file formats: mbx, mh, mmdf, mix, mtx, mx, news, phile,
tenex, unix
. Supported SASL mechanisms: CRAM-MD5, PLAIN, LOGIN, ANONYMOUS
. Sticky UIDs are not supported in the mh, mtx, and tenex drivers
. Creation of keywords is not supported in the mh, mtx, and tenex drivers
. Copy and append of keywords only works in the mbx driver.
. Flat file formats (mbx, mmdf, mtx, phile, tenex, unix) do not permit
mailboxes to have inferior names
. UIDPLUS support is limited to the unix, mmdf, mbx, mx, and mix formats.
. Non-standard IMAP SCAN extension not supported for mh and news formats.
. Win32 (Win9x/NT/Windows 2000) limitations:
. IPv6 is supported in W2K builds but is not the default; you have to use
IP=6 in the nmake command
. Supported local file formats: mbx, mtx, tenex, unix
. Supported SASL mechanisms: CRAM-MD5, PLAIN, LOGIN, ANONYMOUS, GSSAPI
. No server SSL or TLS support.
. No server authentication for GSSAPI
. No server authentication for CRAM-MD5 on NT-based Windows (NT/2K/XP);
it does work on DOS-based Windows (9x/Me).
. Sticky UIDs are not supported in the mtxnt and tenexnt drivers
. Creation of keywords is not supported in the mtxnt and tenexnt drivers
. Copy and append of keywords only works in the mbxnt driver.
. No support for TCP open timeouts
. Flat file formats (mbx, mtx, tenex, unix) do not permit mailboxes to have
inferior names
. UIDPLUS support is limited to the unix and mbx formats.
. Win16 (Win3.1)/DOS limitations:
. IPv6 not supported
. Supported local file formats: bezerk, mtx
. Supported SASL mechanisms: CRAM-MD5, LOGIN, ANONYMOUS
. Supported TCPs: B&W, Novell, PC-NFs, PC/TCP, Waterloo, Winsock
. Sticky UIDs are not supported on local files
. Creation of keywords are not supported on local files
. Bezerk driver is read-only and does not handle LF-only newlines well
. No support for any TCP timeouts on Waterloo DOS
. No support for TCP open timeouts on Winsock and generic DOS
. Flat file formats (bezerk, mtx) do not permit mailboxes to have inferior
names
. Does not work well unless a mailgets routine is armed when fetching
texts.
. Mac limitations:
. IPv6 not supported
. No local file drivers
. Supported SASL mechanisms: CRAM-MD5, LOGIN, ANONYMOUS
. Does not output human-friendly time zone string
. TOPS-20 limitations:
. IPv6 not supported
. No local file drivers
. Supported SASL mechanisms: CRAM-MD5, LOGIN, ANONYMOUS
. No support for any TCP timeouts
. VMS limitations:
. IPv6 not supported
. No local file drivers
. Supported SASL mechanisms: CRAM-MD5, LOGIN, ANONYMOUS
. Supported TCPs: Multinet, Netlib
. No support for any TCP timeouts on VMS Netlib
. No support for TCP open timeouts on VMS Multinet
. Time zone must be configured at build time
. Does not output human-friendly time zone string
. Windows CE limitations:
. IPv6 not yet supported
. No local file drivers
. Supported SASL mechanisms: CRAM-MD5, LOGIN, ANONYMOUS
. No support for TCP open timeouts
. Not finished, only builds c-client library
. OS/2 limitations:
. IPv6 not supported
. Not finished, does not build
yuuji@gentei.org