diff --git a/en_US/howto/relayhost.md b/en_US/howto/relayhost.md
index e0e8553c..91fbffab 100644
--- a/en_US/howto/relayhost.md
+++ b/en_US/howto/relayhost.md
@@ -1,8 +1,12 @@
 # Setup relayhost
 
+[TOC]
+
 Relay host is a server which can accept your email and sent it out to the final
 destination for you.
 
+## Global relay host
+
 To setup a global relay host in iRedMail, please append below settings in
 Postfix config file `/etc/postfix/main.cf` (Linux/OpenBSD) or
 `/usr/local/etc/postfix/main.cf` (FreeBSD):
@@ -35,4 +39,71 @@ postmap hash:/etc/postfix/sasl_password
 service postfix restart
 ```
 
-That's it.
+## Sender dependent relay host
+
+!!! note
+
+    * Sender dependent relay host is available in iRedMail-0.9.5 or later releases.
+
+### Manage with iRedAdmin-Pro
+
+Since iRedAdmin-Pro-SQL-2.4.0 or iRedAdmin-Pro-LDAp-2.6.0, it's able to manage
+per-domain or per-user sender dependent relay host in domain or user profile
+page, under tab "Relay". Screenshot attached.
+
+### Manage with command line tools
+
+#### MySQL, MariaDB, PostgreSQL
+
+For SQL backends, you can manage sender dependent relay host in SQL table
+`mailbox.sender_relayhost`. We use MySQL for example below.
+
+* Per-domain sender dependent relay host:
+
+```
+sql> USE vmail;
+sql> INSERT INTO sender_relayhost (account, relayhost) VALUES ('@domain.com', '[mail.gmail.com]:25');
+```
+
+* Per-user sender dependent relay host:
+
+```
+sql> USE vmail;
+sql> INSERT INTO sender_relayhost (account, relayhost) VALUES ('user@domain.com', '[mail.gmail.com]:25');
+```
+
+#### OpenLDAP
+
+For OpenLDAP backend:
+
+* per-domain sender dependent relay host is stored in attribute `senderRelayHost` of domain account.
+* per-user sender dependent relay host is stored in attribute `senderRelayHost` of user account.
+
+Sample LDIF data:
+
+* Per-domain sender dependent relay host
+
+```
+dn: domainName=mydomain.com,o=domains,dc=example,dc=com
+senderRelayHost: [mail.gmail.com]:25
+...
+```
+
+* Per-user sender dependent relay host
+
+```
+dn: mail=user@mydomain.com,ou=Users,domainName=mydomain.com,o=domains,dc=example,dc=com
+senderRelayHost: [mail.gmail.com]:25
+...
+```
+
+### Screenshot of iRedAdmin-Pro
+
+* iRedAdmin-Pro: Per-domain relay setting:
+
+![](../images/iredadmin/domain_profile_relay.png)
+
+* iRedAdmin-Pro: Per-user relay setting:
+
+![](../images/iredadmin/user_profile_relay.png)
+
diff --git a/html/relayhost.html b/html/relayhost.html
index 010842fa..c28fd8a2 100644
--- a/html/relayhost.html
+++ b/html/relayhost.html
@@ -15,8 +15,27 @@
         <span>iRedMail</span>
     </a>
     &nbsp;&nbsp;//&nbsp;&nbsp;<a href="./index.html">Document Index</a></div><h1 id="setup-relayhost">Setup relayhost</h1>
+<div class="toc">
+<ul>
+<li><a href="#setup-relayhost">Setup relayhost</a><ul>
+<li><a href="#global-relay-host">Global relay host</a></li>
+<li><a href="#sender-dependent-relay-host">Sender dependent relay host</a><ul>
+<li><a href="#manage-with-iredadmin-pro">Manage with iRedAdmin-Pro</a></li>
+<li><a href="#manage-with-command-line-tools">Manage with command line tools</a><ul>
+<li><a href="#mysql-mariadb-postgresql">MySQL, MariaDB, PostgreSQL</a></li>
+<li><a href="#openldap">OpenLDAP</a></li>
+</ul>
+</li>
+<li><a href="#screenshot-of-iredadmin-pro">Screenshot of iRedAdmin-Pro</a></li>
+</ul>
+</li>
+</ul>
+</li>
+</ul>
+</div>
 <p>Relay host is a server which can accept your email and sent it out to the final
 destination for you.</p>
+<h2 id="global-relay-host">Global relay host</h2>
 <p>To setup a global relay host in iRedMail, please append below settings in
 Postfix config file <code>/etc/postfix/main.cf</code> (Linux/OpenBSD) or
 <code>/usr/local/etc/postfix/main.cf</code> (FreeBSD):</p>
@@ -45,7 +64,67 @@ smtp_sasl_security_options = noanonymous
 service postfix restart
 </code></pre>
 
-<p>That's it.</p><p style="text-align: center; color: grey;">All documents are available in <a href="https://bitbucket.org/zhb/iredmail-docs/src">BitBucket repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. If you found something wrong, please do <a href="http://www.iredmail.org/contact.html">contact us</a> to fix it.<script>
+<h2 id="sender-dependent-relay-host">Sender dependent relay host</h2>
+<div class="admonition note">
+<p class="admonition-title">Note</p>
+<ul>
+<li>Sender dependent relay host is available in iRedMail-0.9.5 or later releases.</li>
+</ul>
+</div>
+<h3 id="manage-with-iredadmin-pro">Manage with iRedAdmin-Pro</h3>
+<p>Since iRedAdmin-Pro-SQL-2.4.0 or iRedAdmin-Pro-LDAp-2.6.0, it's able to manage
+per-domain or per-user sender dependent relay host in domain or user profile
+page, under tab "Relay". Screenshot attached.</p>
+<h3 id="manage-with-command-line-tools">Manage with command line tools</h3>
+<h4 id="mysql-mariadb-postgresql">MySQL, MariaDB, PostgreSQL</h4>
+<p>For SQL backends, you can manage sender dependent relay host in SQL table
+<code>mailbox.sender_relayhost</code>. We use MySQL for example below.</p>
+<ul>
+<li>Per-domain sender dependent relay host:</li>
+</ul>
+<pre><code>sql&gt; USE vmail;
+sql&gt; INSERT INTO sender_relayhost (account, relayhost) VALUES ('@domain.com', '[mail.gmail.com]:25');
+</code></pre>
+
+<ul>
+<li>Per-user sender dependent relay host:</li>
+</ul>
+<pre><code>sql&gt; USE vmail;
+sql&gt; INSERT INTO sender_relayhost (account, relayhost) VALUES ('user@domain.com', '[mail.gmail.com]:25');
+</code></pre>
+
+<h4 id="openldap">OpenLDAP</h4>
+<p>For OpenLDAP backend:</p>
+<ul>
+<li>per-domain sender dependent relay host is stored in attribute <code>senderRelayHost</code> of domain account.</li>
+<li>per-user sender dependent relay host is stored in attribute <code>senderRelayHost</code> of user account.</li>
+</ul>
+<p>Sample LDIF data:</p>
+<ul>
+<li>Per-domain sender dependent relay host</li>
+</ul>
+<pre><code>dn: domainName=mydomain.com,o=domains,dc=example,dc=com
+senderRelayHost: [mail.gmail.com]:25
+...
+</code></pre>
+
+<ul>
+<li>Per-user sender dependent relay host</li>
+</ul>
+<pre><code>dn: mail=user@mydomain.com,ou=Users,domainName=mydomain.com,o=domains,dc=example,dc=com
+senderRelayHost: [mail.gmail.com]:25
+...
+</code></pre>
+
+<h3 id="screenshot-of-iredadmin-pro">Screenshot of iRedAdmin-Pro</h3>
+<ul>
+<li>iRedAdmin-Pro: Per-domain relay setting:</li>
+</ul>
+<p><img alt="" src="../images/iredadmin/domain_profile_relay.png" /></p>
+<ul>
+<li>iRedAdmin-Pro: Per-user relay setting:</li>
+</ul>
+<p><img alt="" src="../images/iredadmin/user_profile_relay.png" /></p><p style="text-align: center; color: grey;">All documents are available in <a href="https://bitbucket.org/zhb/iredmail-docs/src">BitBucket repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. If you found something wrong, please do <a href="http://www.iredmail.org/contact.html">contact us</a> to fix it.<script>
   (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
   (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
   m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
diff --git a/zh_CN/installation/_links.md b/zh_CN/installation/_links.md
new file mode 100644
index 00000000..de88e050
--- /dev/null
+++ b/zh_CN/installation/_links.md
@@ -0,0 +1,17 @@
+* 安装 iRedMail：
+
+    * [Red Hat Enterprise Linux, CentOS](./install.iredmail.on.rhel.html)
+    * [Debian, Ubuntu](./install.iredmail.on.debian.ubuntu.html)
+    * [FreeBSD (without Jail)](./install.iredmail.on.freebsd.html), [FreeBSD with Jail (ezjail)](./install.iredmail.on.freebsd.with.jail.html)
+    * [OpenBSD](./install.iredmail.on.openbsd.html)
+
+* After installtion:
+
+    * [Setup DNS records for your iRedMail server (A, PTR, MX, SPF, DKIM)](./setup.dns.html)
+
+* Additional installation tips
+
+    * [Install iRedMail with a remote MySQL server](./install.iredmail.with.remote.mysql.server.html)
+    * [Perform silent/unattended iRedMail installation](./unattended.iredmail.installation.html)
+
+* [Performance tuning for a busy server](./performance.tuning.html)
diff --git a/zh_CN/installation/_title.md b/zh_CN/installation/_title.md
new file mode 100644
index 00000000..e6172b32
--- /dev/null
+++ b/zh_CN/installation/_title.md
@@ -0,0 +1 @@
+安装 iRedMail