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如何通过域名将 IMAP/POP3 连接代理到适当的后端邮件服务器

tag-icon • tag-icon proxy email-server imap pop3
如何通过域名将 IMAP/POP3 连接代理到适当的后端邮件服务器

我的系统包含多个电子邮件服务器（Exchange、Zimbra），用于多个域。因此，当域 A 的用户想要连接到服务器以获取电子邮件时，他们必须使用服务器 A 的 IP（例如：192.168.10.253），域 B 的用户也是如此，他们必须使用服务器 B 的 IP（例如：192.168.20.253）。

我想通过为 IMAP/POP3 连接创建代理服务器来简化用户和邮件服务器之间的连接，但我找不到解决方案，有什么办法吗？请给我关键字或更好的解决方案。非常感谢。

我的问题的图片描述

答案1

这是我的解决方案，希望它有所帮助。

这是我的代理系统架构师

这是 nginx 中的配置

mail {
         auth_http localhost:80/ldap_auth.php;
         pop3_capabilities "TOP" "USER";
         imap_capabilities "IMAP4rev1" "UIDPLUS";

        server {
                listen     110;
                protocol   pop3;
                pop3_auth plain apop cram-md5;
                proxy      on;
        }

        server {
                listen     143;
                protocol   imap;
                proxy      on;
        }
}

这是 ldap_auth.php 中的源代码

<?php
if (!isset($_SERVER["HTTP_AUTH_USER"]) || !isset($_SERVER["HTTP_AUTH_PASS"])) {
    fail();
}

$username = $_SERVER["HTTP_AUTH_USER"];
$userpass = $_SERVER["HTTP_AUTH_PASS"];
$protocol = $_SERVER["HTTP_AUTH_PROTOCOL"];

// default backend port
$backend_port = 110;

if ($protocol == "imap") {
    $backend_port = 143;
}

$backend_ip["domain1.com"] = "10.0.250.251";
$backend_ip["domain2.com"] = "10.0.220.140";

// Authenticate the user or fail
if (!authuser($username, $userpass)) {
    fail();
    exit;
}

$userserver = getmaildomain($username);

$server_ip = (isset($backend_ip[$userserver])) ? $backend_ip[$userserver] : $userserver;

// Pass!
pass($server_ip, $backend_port);

//END

function authuser($user, $pass)
{
    $pass = str_replace('%20', ' ', $pass);
    $pass = str_replace('%25', '%', $pass);
    $emailDomain = getmaildomain($user);
    $emailUsername = getmailuser($user);

    $ldapconfig['host'] = '10.0.250.241';
    $ldapconfig['port'] = '389';
    $ldapconfig['basedn'] = 'ou=' . $emailDomain . ',dc=topdomain,dc=vn';
    $ldapconfig['binduser'] = 'cn=admin,dc=topdomain,dc=vn';
    $ldapconfig['bindpass'] = 'P@ssw0rd';
    $ds = ldap_connect($ldapconfig['host'], $ldapconfig['port']);

    if (isset($ds)) {
        ldap_set_option($ds, LDAP_OPT_PROTOCOL_VERSION, 3);
        ldap_set_option($ds, LDAP_OPT_REFERRALS, 0);
        ldap_set_option($ds, LDAP_OPT_NETWORK_TIMEOUT, 10);

        if (isset($user) && isset($pass)) {
            if (ldap_bind($ds, $ldapconfig['binduser'], $ldapconfig['bindpass'])) {
                if ($search_result = ldap_search($ds, $ldapconfig['basedn'], "(|(uid=%U)(sAMAccountName=%U))")) {
                    $entries = ldap_get_entries($ds, $search_result);
                    if ($entries['count'] == 1) {
                        $dn = $entries[0]['dn'];
                        if (ldap_bind($ds, $dn, $pass)) {
                            return true;
                        } else {
                            return false;
                        }
                    }
                }
            }
        }
    }
    return false;
}

function getmaildomain($user)
{
    return substr($user, strpos($user, '@') + 1);
}

function getmailuser($user)
{
    return substr($user, 0, strpos($user, '@'));
}

function fail()
{
    header("Auth-Status: Invalid login or password");
    exit;
}

function pass($server, $port)
{
    header("Auth-Status: OK");
    header("Auth-Server: $server");
    header("Auth-Port: $port");
    exit;
}

这是 OpenLDAP Font-end 中的配置

include /etc/ldap/schema/core.schema 
include /etc/ldap/schema/corba.schema 
include /etc/ldap/schema/cosine.schema 
include /etc/ldap/schema/duaconf.schema 
include /etc/ldap/schema/dyngroup.schema
include /etc/ldap/schema/inetorgperson.schema
include /etc/ldap/schema/java.schema 
include /etc/ldap/schema/misc.schema 
include /etc/ldap/schema/nis.schema 
include /etc/ldap/schema/openldap.schema 
include /etc/ldap/schema/collective.schema 
include /etc/ldap/schema/pmi.schema 
include /etc/ldap/schema/ppolicy.schema
allow bind_v2
# Define global ACLs to disable default read access.

# Do not enable referrals until AFTER you have a working directory
# service AND an understanding of referrals.
#referral  ldap://root.openldap.org

pidfile     /var/run/slapd/slapd.pid
argsfile    /var/run/slapd/slapd.args

# Load dynamic backend modules: 
modulepath  /usr/lib/ldap 
moduleload  rwm.la
moduleload  back_meta.la 
moduleload  back_ldap.la
loglevel -1
            #######################################################################
# LDAP remote server definitions
            #######################################################################

#Fontend
database meta
suffix "dc=topdomain,dc=vn"
rootdn "cn=admin,dc=topdomain,dc=vn"
rootpw P@ssw0rd

#doamin1.vn - Server
uri "ldap://10.0.250.251/ou=domain1.vn,dc=topdomain,dc=vn"
readonly no 
lastmod off
suffixmassage "ou=domain1.vn,dc=topdomain,dc=vn" "DC=domain1,DC=vn"
map attribute uid sAMAccountName
idassert-bind bindmethod=simple
binddn="CN=ldap,CN=Users,DC=domain1,DC=vn"
credentials="P@ssw0rd"
idassert-authzFrom "dn.exact:cn=admin,dc=topdomain,dc=vn"

#doamin1.vn - Server
uri "ldap://10.0.220.45/ou=domain2.vn,dc=topdomain,dc=vn"
readonly no 
lastmod off
suffixmassage "ou=domain2.vn,dc=topdomain,dc=vn" "DC=domain2,DC=vn"
map attribute uid sAMAccountName
idassert-bind bindmethod=simple
binddn="CN=LDAP Admin,CN=Users,DC=domain2,DC=vn"
credentials="P@ssw0rd"
idassert-authzFrom "dn.exact:cn=admin,dc=topdomain,dc=vn"

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