In this tutorial will learn how to modify iRedMail main daemons which provide mail services, respectively,[Postfix used for mail transfer and Dovecot][4]which delivers mail to accounts mailboxes, in order to integrate them both in[Samba4 Active Directory Domain Controller][5].
By integrating iRedMail to a Samba4 AD DC you will benefit from the following features: user authentication, management, and status via Samba AD DC, create mail lists with the help of AD groups and Global LDAP Address Book in Roundcube.
#### Requirements
1. [Install iRedMail on CentOS 7 for Samba4 AD Integration][1]
### Step 1: Prepare iRedMail System for Sama4 AD Integration
1.On the first step, you need to[assign a static IP address for your machine][6]in case you’re using a dynamic IP address provided by a DHCP server.
Run[ifconfig command][7]to list your machine network interfaces names and edit the proper network interface with your custom IP settings by issuing[nmtui-edit][8]command against the correct NIC.
2.Once the network interface is opened for editing, add the proper static IP settings, make sure you add the DNS servers IP addresses of your Samba4 AD DC and the name of your domain in order to query the realm from your machine. Use the below screenshot as a guide.
3.After you finish configuring the network interface, restart the network daemon to apply changes and issue a series of ping commands against the domain name and samba4 domain controllers FQDNs.
```
# systemctl restart network.service
# cat /etc/resolv.conf # verify DNS resolver configuration if the correct DNS servers IPs are queried for domain resolution
# ping -c2 tecmint.lan # Ping domain name
# ping -c2 adc1 # Ping first AD DC
# ping -c2 adc2 # Ping second AD DC
```
[][11]
Verify Network DNS Configuration
4.Next, sync time with samba domain controller by installing thentpdatepackage and query Samba4 machine NTP server by issuing the below commands:
[][12]
Sync Time with Samba NTP Server
5.You might want the local time to be automatically synchronized with samba AD time server. In order to achieve this setting, add a scheduled job to run every hour by issuing[crontab -e command][13]and append the following line:
[][14]
Auto Sync Time with Samba NTP
### Step 2: Prepare Samba4 AD DC for iRedMail Integration
6.Now, move to a[Windows machine with RSAT tools installed][15]to manage Samba4 Active Directory as described in this tutorial[here][16].
OpenDNS Manager, go to your domainForward Lookup Zonesand add a newArecord, anMXrecord and aPTRrecord to point to your iRedMail system IP address. Use the below screenshots as a guide.
AddArecord (replace the name and the IP Address of iRedMail machine accordingly).
[][17]
Create DNS A Record for iRedMail
AddMXrecord (leave child domain blank and add a 10 priority for this mail server).
[][18]
Create DNS MX Record for iRedMail
AddPTRrecord by expanding toReverse Lookup Zones(replace IP address of iRedMail server accordingly). In case you haven’t configured a reverse zone for your domain controller so far, read the following tutorial:
1. [Manage Samba4 DNS Group Policy from Windows][2]
[][19]
Create DNS PTR Record for iRedMail
7.After you’ve added the basic DNS records which make a mail server to function properly, move to the iRedMail machine, installbind-utilspackage and query the newly added mail records as suggested on the below excerpt.
Samba4 AD DC DNS server should respond with the DNS records added in the previous step.
```
# yum install bind-utils
# host tecmint.lan
# host mail.tecmint.lan
# host 192.168.1.245
```
[][20]
Install Bind and Query Mail Records
From a Windows machine, open aCommand Promptwindow and issue[nslookup command][21]against the above mail server records.
8.As a final pre-requirement, create a new user account with minimal privileges in Samba4 AD DC with the namevmail, choose a strong password for this user and make sure the password for this user never expires.
The vmail user account will be used by iRedMail services to query Samba4 AD DC LDAP database and pull the email accounts.
To create the vmail account, use ADUC graphical tool from a Windows machine joined to the realm with RSAT tools installed as illustrated on the below screenshots or use samba-tool command line directly from a domain controller as explained on the following topic.
1. [Manage Samba4 Active Directory from Linux Command Line][3]
In this guide, we’ll use the first method mentioned above.
[][22]
Active Directory Users and Computers
[][23]
Create New User for iRedMail
[][24]
Set Strong Password for User
9.From iRedMail system, test the vmail user ability to query Samba4 AD DC LDAP database by issuing the below command. The returned result should be a total number of objects entries for your domain as illustrated on the below screenshots.
Note: Replace the domain name and the LDAP base dn in Samba4 AD (‘cn=users,dc=tecmint,dc=lan‘) accordingly.
[][25]
Query Samba4 AD DC LDAP
### Step 3: Integrate iRedMail Services to Samba4 AD DC
10.Now it’s time to tamper with iRedMail services (Postfix, Dovecot and Roundcube) in order to query Samba4 Domain Controller for mail accounts.
The first service to be modified will be the MTA agent, Postfix. Issue the following commands to disable a series of MTA settings, add your domain name to Postfix local domain and mailbox domains and use Dovecot agent to deliver received mails locally to user mailboxes.
```
# postconf -e virtual_alias_maps=' '
# postconf -e sender_bcc_maps=' '
# postconf -e recipient_bcc_maps= ' '
# postconf -e relay_domains=' '
# postconf -e relay_recipient_maps=' '
# postconf -e sender_dependent_relayhost_maps=' '
# postconf -e smtpd_sasl_local_domain='tecmint.lan' #Replace with your own domain
# postconf -e virtual_mailbox_domains='tecmint.lan' #Replace with your own domain
13.Create`/etc/postfix/ad_virtual_group_maps.cf`with the below configuration.
```
server_host = tecmint.lan
server_port = 389
version = 3
bind = yes
start_tls = no
bind_dn = vmail@tecmint.lan
bind_pw = ad_vmail_account_password
search_base = dc=tecmint,dc=lan
scope = sub
query_filter = (&(objectClass=group)(mail=%s))
special_result_attribute = member
leaf_result_attribute = mail
result_attribute= userPrincipalName
debuglevel = 0
```
On all three configuration files replace the values fromserver_host,bind_dn,bind_pwandsearch_baseto reflect your own domain custom settings.
14.Next, open Postfix main configuration file and search and disable iRedAPDcheck_policy_serviceandsmtpd_end_of_data_restrictionsby adding a comment`#`in front of the following lines.
15.Now, verify Postfix binding to Samba AD using an existing domain user and a domain group by issuing a series of queries as presented in the following examples.
The result should be similar as illustrated on the bellow screenshot.
[][26]
Verify Postfix Binding to Samba AD
Replace AD user and group accounts accordingly. Also, assure that the AD group you’re using has some AD users members assigned to it.
16.On the next step modify Dovecot configuration file in order to query Samba4 AD DC. Open file`/etc/dovecot/dovecot-ldap.conf`for editing and add the following lines.
The mailbox of a Samba4 AD account will be stored in/var/vmail/vmail1/your_domain.tld/your_domain_user/Maildir/location on the Linux system.
17.Make sure pop3 and imap protocols are enabled in dovecot main configuration file. Verify if quota and acl mail plugins are also enabled by opening file`/etc/dovecot/dovecot.conf`and check if these values are present.
[][27]
Enable Pop3 and Imap in Dovecot
18.Optionally, if you want to set a global hard quota to not exceed the maximum of 500 MB of storage for each domain user, add the following line in/etc/dovecot/dovecot.conffile.
```
quota_rule = *:storage=500M
```
19.Finally, in order to apply all changes made so far, restart and verify the status of Postfix and Dovecot daemons by issuing the below commands with root privileges.
```
# systemctl restart postfix dovecot
# systemctl status postfix dovecot
```
20.In order to test mail server configuration from the command line using IMAP protocol usetelnetor[netcat command][28]as presented in the below example.
If you can perform an IMAP login from the command line with a Samba4 user account then iRedMail server seems ready to send and receive mail for Active Directory accounts.
On the next tutorial will discuss how to integrate Roundcube webmail with Samba4 AD DC and enable Global LDAP Address Book, customize Roudcube, access Roundcube web interface from a browser and disable some unneeded iRedMail services.
I'am a computer addicted guy, a fan of open source and linux based system software, have about 4 years experience with Linux distributions desktop, servers and bash scripting.
