doc/authentication.txt

   1 **********************************************
   2 IMAP AND SMTP AUTHENTICATION WITH SQUIRRELMAIL
   3 $Id$
   4 Chris Hilts tassium@squirrelmail.org
   5 **********************************************
   6
   7 Prior to SquirrelMail 1.4.0, only plaintext logins for IMAP and SMTP were
   8 supported.  With the release of SquirrelMail 1.4.0, support for the
   9 CRAM-MD5 and DIGEST-MD5 auth mechanisms has been added.  TLS support has
  10 also been added.  It is possible to use different methods for both IMAP and
  11 SMTP. TLS is able to be enabled on a per-service basis as well.
  12 Unless the administrator changes the authentication methods, SquirrelMail
  13 will default to the "classic" plaintext methods, without TLS.
  14
  15 Note: There is no point in using TLS if your IMAP server is localhost. You need
  16 root to sniff the loopback interface, and if you don't trust root, or an attacker
  17 already has root, the game is over.  You've got a lot more to worry about beyond
  18 having the loopback interface sniffed.
  19
  20 REQUIREMENTS
  21 ------------
  22
  23 CRAM/DIGEST-MD5
  24 * SquirrelMail 1.4.0 or higher
  25 * If you have the mhash extension to PHP, it will automatically
  26   be used, which may help performance on heavily loaded servers.
  27   ** NOTE: mhash is optional and no longer a requirement **
  28 * Digest-MD5 authentication needs PHP XML extension.
  29
  30 TLS
  31 * SquirrelMail 1.4.0 or higher
  32 * PHP 4.3.0 or higher (Check Release Notes for PHP 4.3.x information)
  33 * The server you wish to use TLS on must have a dedicated port listening for
  34   TLS connections. (ie. port 993 for IMAP, 465 for SMTP). See STARTTLS
  35   requirements, if you want to use IMAP or SMTP STARTTLS extension.
  36 * If you use PHP 4.3.x, OpenSSL support must be compiled staticly. See
  37   PHP bug #29934 (http://bugs.php.net/bug.php?id=29934)
  38
  39 STARTTLS
  40 * SquirrelMail 1.5.1 or higher
  41 * PHP 5.1.0rc1 or higher (stream_socket_enable_crypto() function)
  42 * Server with STARTTLS extension support
  43
  44 CONFIGURATION
  45 -------------
  46
  47 All configuration is done using conf.pl, under main menu option #2.
  48
  49 conf.pl can now attempt to detect which mechanisms your servers support.
  50 You must have set the host and port before attempting to detect, or you
  51 may get inaccurate results, or a long wait while the connection times out.
  52
  53 If you get results that you know are wrong when you use auto-detection, send
  54 information about it to SquirrelMail developers. Provide the results you got,
  55 the results you expected, and server type, name, and version (eg. "imap,
  56 Cyrus, v2.1.9").
  57
  58 KNOWN ISSUES
  59 ------------
  60
  61 DIGEST-MD5 has three different methods of operation. (qop options "auth",
  62 "auth-int" and "auth-conf").  This implementation currently supports "auth"
  63 only.  Work is being done to add the other two modes.
  64
  65 DIGEST-MD5 _may_ fail when authenticating with servers that supply more
  66 than one "realm".  I have no servers of this type to test on, so if you do
  67 and it fails, let me know!  (A big help would be for you to telnet to your
  68 server, start a DIGEST-MD5 auth session, and include the challenge from the
  69 server in your bug report.)
  70
  71 To get the challenge with IMAP:
  72    telnet <your server> imap
  73    [server says hello]
  74    A01 AUTHENTICATE DIGEST-MD5
  75    <copy the gobbledygook that the server sends - this is what I need>
  76    *
  77    [server says auth aborted]
  78    A02 LOGOUT
  79    [server says goodbye, closes connection]
  80
  81 To get the challenge with SMTP:
  82    telnet <your server> smtp
  83    [server sends some sort of "hello" banner]
  84    EHLO myhostname
  85    [server will probably list a bunch of capabilities]
  86    AUTH DIGEST-MD5
  87    <copy the gobbledygook that the server sends - this is what I need>
  88    *
  89    [server says auth aborted]
  90    QUIT
  91    [server says bye, closes connection]
  92
  93
  94 OPTIONAL SMTP AUTH CONFIGURATION
  95 --------------------------------
  96
  97 If you need all users to send mail via an upstream SMTP provider
  98 (your ISP, for example), and that ISP requires authentication,
  99 there are two variables that can be added to config_local.php
 100 that will specify a sitewide SMTP username and password.
 101
 102 Set up SMTP authentication to the remote server according to the
 103 instructions above, then add the following to config_local.php,
 104 replacing <smtp_user> and <smtp_pass> with the username and password
 105 you'd like to use for the entire site:
 106
 107    $smtp_sitewide_user = '<smtp_user>';
 108    $smtp_sitewide_pass = '<smtp_pass>';
 109
 110 These values will be used to connect to the SMTP server as long
 111 as the authentication mechanism is something besides 'none', i.e.
 112 'login','plain','cram-md5', or 'digest-md5'.
 113
 114 DEBUGGING SSL ERROR MESSAGES
 115 ----------------------------
 116
 117 SquirrelMail disables display of PHP errors in fsockopen() and
 118 stream_socket_enable_crypto() function calls. These functions use PHP error
 119 handler to display connection errors and SquirrelMail tries to handle
 120 errors without displaying debugging information to end user. If you use TLS or
 121 STARTTLS and get connection errors, try reproducing them in configtest.php
 122 script or remove @ symbol from fsockopen() and stream_socket_enable_crypto()
 123 calls in SquirrelMail scripts.
 124
 125 Possible error messages:
 126 * SSL: Connection reset by peer in some script.
 127   Error happened in IMAP server and server dropped connection. It is possible
 128   that error is logged in system or imap logs.
 129
 130 * SSL operation failed with code 1. OpenSSL Error messages: error:14094410:SSL
 131 routines:func(148):reason(1040) in some script.
 132   Error generated by SSL libraries. Locate numbers listed 'SSL
 133   routines:func(###):reason(####)' string, find ssl.h file in your OpenSSL
 134   sources and locate same numbers listed in '/* Error codes for the SSL
 135   functions. */' section. Error define can be self explanatory. If you don't
 136   understand it, search for error or that define in your favorite search
 137   engine.
 138
 139
 140 [End]