PHP 8.4.0 RC4 available for testing

imap_open

(PHP 4, PHP 5, PHP 7, PHP 8)

imap_openメールボックスへの IMAP ストリームをオープンする

説明

imap_open(
    string $mailbox,
    string $user,
    string $password,
    int $flags = 0,
    int $retries = 0,
    array $options = []
): IMAP\Connection|false

mailbox への IMAP ストリームをオープンします。

この関数は、POP3NNTP サーバーへのストリームをオープンする際にも使用可能です。 しかし、いくつかの関数および機能は IMAP サーバーでしか利用できません。

パラメータ

mailbox

メールボックス名(mailbox)は、サーバー名の部分と使用するサーバーにおける メールボックスへのパスから構成されます。特別な名前 INBOX は、 カレントユーザーの個人メールボックスを意味します。 ASCII 空間で出力可能な文字以外の外国文字を含むメールボックス名は imap_utf7_encode() でエンコードする必要があります。

警告

信頼できないデータをこのパラメータに渡すのであれば、 imap.enable_insecure_rsh を無効にしておかなければ危険です。

サーバー部は '{' および '}' で括られ、サーバー名または IP アドレス、オプションの ':' から始まるポート指定子、('/' で始まる)オプションのプロトコル指定子 から構成されます。

サーバー部は、全ての mailbox パラメータで必須です。

{ で始まる名前はすべてリモート名で、 "{" remote_system_name [":" port] [flags] "}" [mailbox_name] のような形式となります。

  • remote_system_name - Internet ドメイン名 あるいは括弧でかこまれたサーバーの IP アドレス。
  • port - オプションの TCP ポート番号。デフォルトは そのサービスのデフォルトポート。
  • flags - オプションのフラグ。以下の表を参照ください。
  • mailbox_name - リモートメールボックス名。デフォルトは INBOX 。

オプションのフラグ名
フラグ 説明
/service=service メールボックスにアクセスするサービス。デフォルトは "imap" 。
/user=user サーバーへのログイン時のユーザー名。
/authuser=user リモートの認証ユーザー。指定されていた場合は、このユーザーのパスワードが 認証に使用されます(例: administrator)。
/anonymous 匿名ユーザーとしてアクセスします。
/debug プロトコルの通信内容をアプリケーションのデバッグログに記録します。
/secure ネットワーク越しにプレーンテキストのパスワードを送信しません。
/imap, /imap2, /imap2bis, /imap4, /imap4rev1 /service=imap と同じです。
/pop3 /service=pop3 と同じです。
/nntp /service=nntp と同じです。
/norsh 事前に認証済みの IMAP セッションを確立する際に、rsh や ssh を使用しません。
/ssl セッションの暗号化に Secure Socket Layer を使用します。
/validate-cert TLS/SSL サーバーの証明書を検証します(デフォルトの挙動です)。
/novalidate-cert TLS/SSL サーバーの証明書を検証しません。サーバーが自己証明の 証明書を使用している際に必要となります。
/tls セッションの暗号化に start-TLS の使用を強制し、それを サポートしていないサーバーとの接続を拒否します。
/notls たとえサーバーがそれをサポートしていたとしても、 セッションで start-TLS による暗号化を使用しません。
/readonly 読み込み専用でのメールボックスのオープンを要求します(IMAP のみ。 NNTP では無視され、SMTP および POP3 ではエラーとなります)。

user

ユーザー名。

password

user のパスワード。

flags

flags はビットマスクであり、以下の組み合わせとなります。

  • OP_READONLY - メールボックスを読み込み専用でオープンします。
  • OP_ANONYMOUS - news に関して .newsrc を使用せず、更新もしません(NNTP のみ)。
  • OP_HALFOPEN - IMAP 及び NNTP 名について、 接続をオープンしますがメールボックスはオープンしません。
  • CL_EXPUNGE - メールボックスを閉じる際に、 自動的にメールボックスを削除します(imap_delete() および imap_expunge() も参照ください)。
  • OP_DEBUG - プロトコルネゴシエーションをデバッグします。
  • OP_SHORTCACHE - 短い(elt-only)キャッシングを行います。
  • OP_SILENT - イベントを受信しません(内部で使用します)。
  • OP_PROTOTYPE - ドライバのプロトタイプを返します。
  • OP_SECURE - セキュアでない認証を行いません。

retries

接続試行の最大数。

options

接続パラメータ。次の (文字列の) キーを使って接続パラメータを設定することができます。

  • DISABLE_AUTHENTICATOR - 認証プロパティを無効にする

戻り値

成功した場合は、 IMAP\Connection クラスのインスタンスを返します。 失敗した場合に false を返します.

変更履歴

バージョン 説明
8.1.0 IMAP\Connection のインスタンスを返すようになりました。 これより前のバージョンでは、 リソース を返していました。

例1 imap_open() のさまざまな使用例

<?php
// ローカルマシンのポート 143 で稼動している IMAP サーバーに接続するには
// 以下のようにします。
$mbox = imap_open("{localhost:143}INBOX", "user_id", "password");

// ローカルマシンのポート 110 で稼動している POP3 サーバーに接続するには、
$mbox = imap_open ("{localhost:110/pop3}INBOX", "user_id", "password");

// SSL IMAP あるいは POP3 サーバーに接続するには、プロトコル指定のあとに
// /ssl を追加します。
$mbox = imap_open ("{localhost:993/imap/ssl}INBOX", "user_id", "password");

// 自分でサインした証明書で SSL IMAP あるいは POP3 サーバーに接続するには、
// プロトコル指定のあとに /ssl/novalidate-cert を追加します。
$mbox = imap_open ("{localhost:995/pop3/ssl/novalidate-cert}", "user_id", "password");

// ローカルマシンのポート 119 で稼動している NNTP サーバーに接続するには、
$nntp = imap_open ("{localhost:119/nntp}comp.test", "", "");
// リモートサーバーに接続する際は、"localhost" を接続したいサーバーの
// 名前または IP アドレスに置き換えます。
?>

例2 imap_open() の例

<?php
$mbox
= imap_open("{imap.example.org:143}", "username", "password");

echo
"<h1>Mailboxes</h1>\n";
$folders = imap_listmailbox($mbox, "{imap.example.org:143}", "*");

if (
$folders == false) {
echo
"コールが失敗しました<br />\n";
} else {
foreach (
$folders as $val) {
echo
$val . "<br />\n";
}
}

echo
"<h1>INBOX のヘッダ</h1>\n";
$headers = imap_headers($mbox);

if (
$headers == false) {
echo
"コールが失敗しました<br />\n";
} else {
foreach (
$headers as $val) {
echo
$val . "<br />\n";
}
}

imap_close($mbox);
?>

参考

add a note

User Contributed Notes 37 notes

up
29
php at dsgvoseidank dot de
2 years ago
Google dropped the support of user/password authentication as of 30 may 2022.
imap_open can not be used anymore, without the support of xoauth2.
https://support.google.com/accounts/answer/6010255

There is a ToDo from 2020 that didn't make it.
https://wiki.php.net/todo/ext/imap/xoauth2

The only way is to switch to a third party lib. "php-imap"
This is so sad.
up
7
neekToO
2 years ago
To reply to "dsgvoseidank" saying it doesnt work anymore with Gmail :

As today 26 august 2022 it is still working but you need to use google parameters to generate a password for your app on a 2FA account
up
13
kay at rrr dot de
14 years ago
imap_open is very simple to use, but struggles a litte bit on setups with ssl and tls.

this are tested examples for different hosts and protocols.

uncomment the host/protocol line and fill in correct username and password.

Kay

<?php

#######
# localhost pop3 with and without ssl
# $authhost="{localhost:995/pop3/ssl/novalidate-cert}";
# $authhost="{localhost:110/pop3/notls}";

# localhost imap with and without ssl
# $authhost="{localhost:993/imap/ssl/novalidate-cert}";
# $authhost="{localhost:143/imap/notls}";
# $user="localuser";

# localhost nntp with and without ssl
# you have to specify an existing group, control.cancel should exist
# $authhost="{localhost:563/nntp/ssl/novalidate-cert}control.cancel";
# $authhost="{localhost:119/nntp/notls}control.cancel";

######
# web.de pop3 without ssl
# $authhost="{pop3.web.de:110/pop3/notls}";
# $user="kay.marquardt@web.de";

#########
# goggle with pop3 or imap
# $authhost="{pop.gmail.com:995/pop3/ssl/novalidate-cert}";
# $authhost="{imap.gmail.com:993/imap/ssl/novalidate-cert}";
# $user="username@gmail.com";

$user="username like above";
$pass="yourpass";

if (
$mbox=imap_open( $authhost, $user, $pass ))
{
echo
"<h1>Connected</h1>\n";
imap_close($mbox);
} else
{
echo
"<h1>FAIL!</h1>\n";
}

?>
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12
jeff at newscloud dot com
10 years ago
One of the issues with gmail IMAP SSL authentication is related to Google's account security.

Once you get the login error once, sign out of all your google accounts. Then, visit this link:
http://www.google.com/accounts/DisplayUnlockCaptcha

Log in with the account you're attempting to access via imap.

Follow the steps and you'll then be able to login in to gmail with php imap.

It's visually shown here:
http://jeffreifman.com/filtered-open-source-imap-mail-filtering-software-for-php/configuring-gmail/
up
13
guilherme dot geronimo at gmail dot com
13 years ago
Using:
<?php
imap_open
( "{server.example.com:143}INBOX" , 'login' , 'password' );
?>

Got this error:
"Couldn't open stream {server.example.com:143}INBOX"

Solved by adding the flag "novalidate-cert":
<?php
imap_open
( "{server.example.com:143/novalidate-cert}INBOX" , 'login' , 'password' );
?>

=D
up
6
hashampel at yahoo dot de
10 years ago
Subfolders of INBOX have to be seperate by dot like this: 'INBOX.test'
$mailbox = '{example.example.com:143/imap/novalidate-cert}INBOX.test'
up
4
dominic_mayers at yahoo dot com
7 years ago
This code demonstrates features that are not well documented at this time. The main feature is that the selected mailbox in imap_open (or reopen) and the specified mailbox in other imap functions are unrelated. It has been tested with Gmail and with a Dovecot IMAP server. The mailbox separator depends on the server. Gmail: "/" Dovecot: "." If you want to test with Gmail, you need to turn on "Access for less secure apps" in your account.

<?php
// Change these.
$server = "{imap.gmail.com:993/imap/ssl/novalidate-cert}";
$email = "example@gmail.com";
$password = "password";

// The code assumes that the folders Test/Sub1/Sub11, etc. exist.
$selected = "{$server}Test/Sub1/Sub12";
$conn = imap_open($selected, $email , $password);

// This returns the $specified mailbox and its sub mailboxes,
// even if the $specified mailbox is outside the $selected mailbox.
$specified = "{$server}Test/Sub1";
$boxes = imap_list($conn, $specified , '*');
print_r($boxes);

// This appends the message in the $specified mailbox.
// It ignores the $selected mailbox.
imap_append($conn, $specified
, "From: me@example.com\r\n"
. "To: you@example.com\r\n"
. "Subject: test\r\n"
. "\r\n"
. "this is a test message, please ignore\r\n");

// This changes the $selected mailbox
$selected = "{$server}Test/Sub1";
imap_reopen($conn, $selected);

// This moves a message from the $selected to the $specified mailbox
// In this case, the specified mailbox does not include the server.
imap_mail_move ($conn , "1" , "Test");
imap_expunge($conn);
imap_close($conn);
// If you executed this code with a real IMAP server,
// the message is now in the Test mailbox !
?>
up
4
me at achronos dot ca
10 years ago
Do not bother using "/debug" flag in $mailbox or OP_DEBUG in $options. They do not do anything.

When you set either one, the underlying IMAP c-client library will gather protocol debugging data and pass it back to PHP.
However, the debug handler defined by PHP is an empty function, it doesn't do anything.

So unless you're using a customized version of the IMAP extension that does something with that handler (mm_dlog), there is no point using "/debug" or OP_DEBUG.
up
1
LANGE.LUDO
5 years ago
If you get Kerberos errors like:
« Notice: Unknown: Kerberos error: Credentials cache file '/tmp/krb5cc_0123' not found (try running kinit) ».

Try to add as a $param:
<?php array('DISABLE_AUTHENTICATOR' => 'GSSAPI') ?>

eg.
<?php
$imap_stream
= imap_open('{mail.domain.tld:993/imap/ssl}' , 'username' , 'password', null, 1, array('DISABLE_AUTHENTICATOR' => 'GSSAPI'));
?>
up
1
Lisboa
9 years ago
The error: Unknown: Mailbox is empty (errflg=1) in Unknown on line 0
appears when:

1) use imap_open to connect
2) then use imap_search ALL to retrieve emails

but there are no messages available. To avoid this error, check first the number of messages in a mailbox using imap_status. Only if there are messages available then you can use the imap_search.
up
5
Martin Eckardt
13 years ago
Since Version 5.3.2 there's a 6th parameter available to disable authentication with GSSAPI or NTLM:

Example:
<?php
$mbox
= imap_open("{w2010ExchangeServer:993/imap/ssl}", $user, $password, NULL, 1, array('DISABLE_AUTHENTICATOR' => 'GSSAPI'));
?>

This solves the problem with Exchange 2010 for me. As a reference see https://bugs.php.net/bug.php?id=33500
up
2
Anonymous
6 years ago
Function to test most of the possible options of a connection:

function imapConfig($options, $i=0, $till = array()) {
if(sizeof($options)==$i)
return $till;

if(sizeof($till)==0)
$till[] = '';

$opt = $options[$i];
$new = array();
foreach($till as $t) {
foreach($opt as $o) {
if(strlen($o)==0)
$new[] = $t;
else
$new[] = $t.'/'.$o;
}
}
return imapConfig($options, $i+1, $new);
}

function imap_test($server, $port, $dir, $username, $passw) {
$options = array();
//$options[] = array('debug');
$options[] = array('imap', 'imap2', 'imap2bis', 'imap4', 'imap4rev1', 'pop3'); //nntp
$options[] = array('', 'norsh');
$options[] = array('', 'ssl');
$options[] = array('', 'validate-cert', 'novalidate-cert');
$options[] = array('', 'tls', 'notls');

$configOptions = imapConfig($options);
foreach($configOptions as $c) {
$mbox = @imap_open("{".$server.":".$port.$c."}".$dir, $username, $passw);
echo "<b>{".$server.":".$port.$c."}".$dir."</b> ... ";
if (false !== $mbox) {
echo '<span style="color: green"> success</span>';
}
else {
echo '<span style="color: red"> failed</span>';
}
echo '<br>';
}
}

imap_test('mail.server.de', 143, 'INBOX', 'username', 'pwd');
up
2
liamr at umich dot edu
20 years ago
To authenticate using kerberos V / GSSAPI, you might need to add "user=" to the connection string.. eg:

$mbox = imap_open( "\{imap.example.com:143/imap/notls/user=" . $user . "}INBOX", $user, $passwd );

Our IMAP servers won't allow a user other than the user specified in the kerberos credentials connect using those credentials unless you specify that extra "user=" in the connection string. Passing it as an argument to imap_open() doesn't seem to be enough.
up
2
shaikh_zaid at yahoo dot com
18 years ago
imap_open will not open a stream if your server operates with Transport Layer Security (i.e. TLS) imap_open connects with SSL if its there. So try opening mailbox as

$mailbox="{mail.domain.com:143/imap/notls}";
or
$mailbox="{mail.domain.com:110/pop3/notls}"; This works...

Some mail server requires you to provide username@domain.com so you can always use. user@doamin.com

$conn=imap_open($mailbox, $username, $password);

Some server may ask for username as "user=user@domain.com"

:)
up
2
rvarkelen AT hortimax.nl
20 years ago
In order to make a IMAP connection to a Microsoft Exchange Server 5.5, I used this connection-string :

<?php
if(imap_open ("{192.168.1.6:143/imap}Inbox", "DOMAIN/USERNAME/ALIAS", "PASSWORD"))
{
echo
'Connection success!';
}
else
{
echo
'Connection failed';
}
?>

By replacing "Inbox" with, e.g. "Tasks", its possible to see all your tasks. I Hope this helps anybody!

Regards
up
3
frederik at roal dot no
22 years ago
For all imap functions where you specify the mailbox string it is important that you ALWAYS use IP (not hostname) and the portnumber. If you do not do this imap functions will be painfully slow.
Using hostname instead of IP adds 3 seconds to each IMAP call, not using portnumber adds 10 seconds to each imap call. (hint: use gethostbyname() )
up
1
mightycpa
15 years ago
My script kept on timing out, even though the syntax was spot on... ultimately, I figured out that the port was blocked by my webhost, where I ran this on a shared server...

I post this just in case you miss this obvious, like I did.
up
1
avizion at relay dot dk
19 years ago
For FreeBSD users...

If you want to have SSL support, you want to install the ports:

mail/php5-imap
security/php5-openssl

Cheers :)

- avizion
up
2
brojann at netscape dot com
23 years ago
You can do

<? $foo = imap_errors(); ?>

to clear unwanted warning messages like 'Mailbox is empty'
up
1
m dot stoel at cyberkinetic dot nl
19 years ago
a little tip for those who get really frustrated even after reading all the right solutions and implementing them but still get the same errors or none at all..:
after having changed the code.. restart the httpd deamon..

for Fedora or any other Red Hat Linux OS (/etc/init.d/httpd restart).

After this you will be able to make a imap/pop3 stream from apache..
up
1
kaper at nexgc dot com
21 years ago
I had been having lots of trouble trying to get imap_open to connect to an imap server. Then I found another post online that suggested this and it worked, so I am going to post it here. I hope this helps others..

"I have tried with the following strings instead and it works:

for pop3: {www.server.com:110/pop3/notls}INBOX

and for imap: {www.server.com:143/notls}INBOX.
up
0
Stefano
1 year ago
``There is one thing I learned over the years,
if someone says: "it's not possible", prove them wrong.`` ~ Stefano Kocka '99

test date: 2022-11-20
php version: PHP 8.0.10 (cli)
extension=imap
extension=openssl

imap: IMAP c-Client Version => 2007f
SSL Support => enabled

https://support.google.com/accounts/answer/185833?hl=en

<?php
$cnx
= '{imap.gmail.com:993/imap/ssl/readonly}';
$mbox = imap_open($cnx, 'user@gmail.com', 'MyAppPassword');
$folders = imap_listmailbox($mbox, $cnx, '*');
print_r($folders);
/*
Array
(
[0] => {imap.gmail.com:993/imap/ssl/readonly}INBOX
[1] => {imap.gmail.com:993/imap/ssl/readonly}LABEL1
[2] => {imap.gmail.com:993/imap/ssl/readonly}LABEL2
[3] => {imap.gmail.com:993/imap/ssl/readonly}Queue
[4] => {imap.gmail.com:993/imap/ssl/readonly}[Gmail]/All
[5] => {imap.gmail.com:993/imap/ssl/readonly}[Gmail]/Drafts
[6] => {imap.gmail.com:993/imap/ssl/readonly}[Gmail]/Sent
[7] => {imap.gmail.com:993/imap/ssl/readonly}[Gmail]/Spam
[8] => {imap.gmail.com:993/imap/ssl/readonly}[Gmail]/Starred
[9] => {imap.gmail.com:993/imap/ssl/readonly}[Gmail]/Trash
)
*/
?>
Kind regards
up
0
Ap.Muthu
9 years ago
An old archived 2006 PHP script to retrieve IMAP POP3 email into a MySQL database and as files is at:
http://web.archive.org/web/20060411020022/http://www.sellchain.com/phPOP3/phPOP3.txt
up
0
egoman69 at hotmail
14 years ago
"Couldn't open stream {127.0.0.1:143/imap/notls}INBOX"

Solved by only replacing 127.0.0.1 with localhost, php and IMAP server both in same machine, not through Proxy or anything. Weird!
up
-1
askalski at synacor dot com
17 years ago
By default, imap_open() will retry an incorrect password 3 times before giving up. This is a feature built into the c-client library intended for interactive mail clients (which can prompt the end user for a new username/password combo.)

The new optional parameter "$n_retries" allows PHP to override the default retry limit. There is absolutely no reason to leave this at default, or to set it to any value other than 1. This is especially important if the mail server you're using locks users out after too many login failures.
up
-1
itstooloud
17 years ago
Works with Gmail's new IMAP function for personal and for Google Apps.

$mbox = imap_open ("{imap.gmail.com:993/imap/ssl}INBOX", "username@gmail.com", "password")
or die("can't connect: " . imap_last_error());
up
-1
david at brayworth dot com dot au
13 years ago
I managed to use this function against Exchange 2010 without recompiling to disable kerberos

It's important to me that php installs per the standard package (yum install php)

Exchange 2010 triggers kerberos in php, and you require the kinit thing (search around google for "imap_open kinit exchange 2010" and you will find this)

To get it working I had to:
1. setup the krb5.conf file correctly
2. do a kinit username@DOMAIN.DOM with a valid username / password
3. rename the ticket file to reflect the user id of apache (usually 48)
/tmp/krb5cc_48
4. fix ownership
chown apache.apache /tmp/krb5cc_48

but the exchange server will use the kerberos ticket and not the username password - unless you use ssl

<?php

$imap_user
= "username";
$imap_pass = "password";
$imap_server = "{w2010kExchangeServer:993/novalidate-cert/ssl}";

$mbox = imap_open("{$imap_server}INBOX", $imap_user, $imap_pass);

$sorted_mbox = imap_sort($mbox, SORTDATE, 0);
$totalrows = imap_num_msg($mbox);
print
"$imap_server\n";

$startvalue = 0;
while (
$startvalue < $totalrows) {

$headers = imap_fetchheader($mbox, $sorted_mbox[ $startvalue ] );
$subject = array();
preg_match_all('/^Subject: (.*)/m', $headers, $subject);
print
$subject[1][0] . "\n";

$startvalue++;
}
?>

One small step for php / exchange, one Giant leap for David ....
up
-1
Tim
9 years ago
Hi

I was struggling with the Gmail Imap/pop connection. It keeps saying too many failed login connections were made.

Thing I did:
https://www.google.com/settings/security/lesssecureapps
Clicked "Turn on"
> worked!

So last step could be used but remember your account will be at a certain security risk. Anyway it comes in handy to develop...
up
-2
jeff1326
13 years ago
If your connection is too slow, try it with port and without domain.

<?php
//Normal connection
$mailbox = imap_open("{SERVER}INBOX", $username, $password);

//Faster connection
$mailbox = imap_open("{SERVER:143}INBOX", $username, $password);

//Very slow connection
$mailbox = imap_open ("{SERVER.DOMAIN}INBOX", "DOMAIN/".$username, $password);
?>
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bandpay at hotmail dot com
23 years ago
I have a single comment to add about imap_open.
If you want to connect to a news server, without specifying any news gruop, you can use the following:

<?php
$server
= "{news.servername.com/nntp:119}";
$nntp = imap_open($server,"","",OP_HALFOPEN);
?>

and $nntp will become the connection ID.

Regards
//Babak
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phpnet at danepowell dot com
12 years ago
If you are accessing a local mailbox file, i.e. imap_open('/var/mail/www-data', '', ''), you may be restricted in what files you can access.

If PHP IMAP was compiled with the restrictBox option (which I believe most packages are these days), you can only access files relative to $HOME. Paths starting with '/' or '../' will be rejected.
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reg1barclay at REMOVETHIS dot live dot it
6 years ago
On Windows, this function does not use certificates in directories listed by openssl_get_cert_locations(): it use system's certificates store. If you want to use a certificate signed by a test authority, you must add root certificate of your test authority to Window's certificates store.
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-1
Valerio Pulese
8 years ago
If you get slow imap4/pop3 authentication step
i.e. 5-10 sec just for response, maybe you are connecting to an imap server which is advertising GSSAPI auth mechanism.
Martin Eckardt note could help to speed it up.
<?php
$mbox
= imap_open("{imap server with GSSAPI :993/imap/ssl}", $user, $password, NULL, 1, array('DISABLE_AUTHENTICATOR' => 'GSSAPI'));
?>

Disable GSSAPI if you dont use it.
If your imap/pop server is Dovecot
/etc/dovecot/conf.d/10-auth.conf
...
auth_mechanisms = plain login gssapi
-> auth_mechanisms = plain login
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Brian Law
10 years ago
imap_open()
validate SSL certificate does not support Subject Alternative Name (SAN) certificate. It only validate against the Subject/Common name.
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-1
oz49erfan
14 years ago
Make sure your PHP is enabled with imap via the phpinfo() function

'--with-imap-dir=/opt/lampp' '--with-imap-ssl' '--with-imap=/opt/lampp'

and

IMAP c-Client Version 2007e
SSL Support Yes

I noticed that my apache script was working but my cli script was not. Turns out my php cli executable didn't have imap setup so I had to use another php cli executable.
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marshall /AT\ pacdemon.org
21 years ago
Thanks for all your comments. The user comments have saved me countless times.

I'd like to give back in my small way by providing this little tip. To test your pop or imap services you can use telnet (almost all operating systems should come with a command line telnet client).

Here's the pop3 example (the lines that start with + are the server's response):

telnet your.pop.host.com 110
+OK POP3 your.pop.host.com v2001.78 server ready
user your_username
+OK User name accepted, password please
pass your_password
+OK Mailbox open, 23 messages

Note that your pop server may be on some other port than 110 but that is the default/standard.

Here's the imap example (Lines that have OK near the begining are server responses):

telnet your.imap.host.com 143
* OK [CAPABILITY IMAP4REV1...]
1 LOGIN "your_username" "your_password"
1 OK [CAPABILITY...] ... User your_username authenticated

This might be old news to some people but I hope it's helpful for many.
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chris at ocproducts dot com
4 years ago
imap_open supports SSL/TLS and start-TLS, and also totally unencrypted sessions.

The documentation here slightly conflates things.

Where it is referring to SSL (/ssl) it is really referring to SSL/TLS of the immediate variety. The initial connection will immediately be SSL/TLS, rather than later upgraded. (I don't know the specifics about which versions of SSL/TLS c-client is going to be negotiating/using.)

The '/tls' and '/notls' options are just about start-TLS, i.e. upgraded connections.

Note there is a '/notls' option but not a '/nossl' option. That is because by default c-client is going to upgrade to TLS (start-TLS) when it sees it as an advertised option by the IMAP server. i.e. it is going to do it based on auto-detection. The '/notls' option disables that auto-detection, which is sometimes necessary. For example, I just helped someone whose IMAP server advertises start-TLS to connections on port 143 but it actually only works on port 993. Regular SSL/TLS doesn't do any auto-detection as the connection mode has to be explicitly made upfront anyway.
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