ZCS does not natively support Procmail, and hence there are 3 ways to use procmail with ZCS:

1. Use ZCS with a MTA set to a server/installation with procmail configured (e.g. ZCS has a MTA set to another machine which has postfix with procmail configured and all the filtering is done by that server)
2. Use ZCS as normal, and run procmail on your mailbox (through the procmailrc file), to do the sorting/filtering.
3. Use ZCS with procmail as a pipe for mail delivery. (This guide will discuss this way of using procmail.)

Let’s assume:

• The mail server with ZCS has already been installed and configured. If not, check my ZCS installation guide and install ZCS.
• We want to use procmail to filter all emails.
• We want to discard emails with attachments that are destined for outside of our domain (i.e. test-example.com), but allow email with attachments for inside our domain.
• We are using a CentOS 6 machine (works on Fedora, RHEL as well).
• sudo is configured for the user or we are executing commands as root user.

Install Procmail

sudo yum -y install procmail

Set ZCS Transport Map

• Login as zimbra user.

su - zimbra

• Check the currently configured transport map for postfix:

cat /opt/zimbra/postfix/conf/main.cf | grep transport_maps

The output should look like:

transport_maps = proxy:ldap:/opt/zimbra/conf/ldap-transport.cf

• Add the transport file to the zimbra configuration.

zmlocalconfig -e postfix_transport_maps=' hash:/opt/zimbra/postfix/conf/transport,proxy:ldap:/opt/zimbra/conf/ldap-transport.cf'

• Add procmail pipe to the transport file (requires to edit the file as root user).

su -
vim /opt/zimbra/postfix/conf/transport

Add the following content to the file:

*    procmail-pipe

• Create the db file for the transport map.

su - zimbra
postmap /opt/zimbra/postfix/conf/transport

• For the pipe to work, a corresponding set of configuration needs to be done in the postfix’s master.cf file. In this case master.cf.in file.

vim /opt/zimbra/postfix/conf/master.cf.in

Add the following text at the end of the file:

procmail-pipe    unix    -    n    n    -    -    pipe
flags=    user=zimbra    argv=/usr/bin/procmail /opt/zimbra/procmail/procmailrc

Create the Procmail Recipe

• Create the Procmail recipe file (i.e. /opt/zimbra/procmail/procmailrc file that we have configured in the previous step).

mkdir /opt/zimbra/procmail/
cd /opt/zimbra/procmail/
touch procmailrc
chown -R zimbra:zimbra .
vim procmailrc

Add the following content to the file:

SHELL = /bin/sh
PATH=$HOME/bin:/usr/bin:/bin:.
MAILDIR=/opt/zimbra/procmail/ # You better make sure it exists
DEFAULT=$MAILDIR
LOGFILE=.procmaillog
LOCKFILE=.procmaillock
VERBOSE=yes

:0
* !To:.*test-example\.com.*
* ! ^Content-Type:.*text/plain.*
{
:0B
* ^(Content-(Type|Disposition):.*|[ ]*(file)?)name=("[^"]*|[^]*)\..*
/dev/null
}

• Restart Postfix.

zmmtactl stop
zmmtactl start

Thanks to the Zimbra forum entry and Zimbra Wiki on Configuring Postfix to work with piped scripts from where I adapted my installation and hence wrote this guide.

Further Reading

• Postfix Dedicated Transport Howto
• Configuring Postfix to work with piped scripts - Zimbra :: Wiki
• Postfix manual - transport(5)
• Zimbra and procmail - Zimbra :: Forums

CentOS Version: 6.0 x86_64
ZCS Version: 7.1.3 GA 3664 for RHEL 6 x86_64 Open Source (Release 7.1.3_GA_3346.RHEL6_64_20110928134428)

This guide will take you through installing Zimbra Collaboration Server (ZCS) which is an integrated bundle of Mail Server, web-documents, and other collaboration services enriched with easy web-administration interfaces. This makes ZCS a good choice for those who do not want to install and configure all the tools and service needed to support the features required for email, and web administration + web-mail interface is quite a time and effort saving feature of ZCS.

This guide makes a few assumptions about the prerequisites that have already been made/configured/handled:

• The server will handle email for the domain test-example.com.
• The server will be hosted on a machine named mail.test-example.com.
• The DNS is properly set up for resolving the names, and as well as for the MX record for test-example.com.
• The machine for mail server has access to the DNS server and can resolve names.
• The installer for ZCS (RHEL 6) has been downloaded.
• The mail server has access to the Internet (for installing/updating packages, as well as to contact external relay MTA)
• sudo is configured for the user, or the commands are used as root user.

Pre-Installation Tweaks

• Disable system installed postfix/sendmail as ZCS runs its own postfix. System-wide installed postfix/sendmail interferes with ZCS’s postfix.

sudo service postfix stop
sudo chkconfig postfix off
sudo service sendmail stop
sudo chkconfig sendmail off

• Install nc package

sudo yum -y install nc

• Disable SELinux (I’ve not yet found a way to use ZCS with SELinux on).

vim /etc/sysconfig/selinux

In the file, set:

SELINUX=disabled

sudo setenforce 0

• Allow a few ports for Zimbra beforehand (not required before installation, but makes no harm in pre-setting it)

sudo iptables -I INPUT -p tcp --dport 443 -j ACCEPT #HTTPS
sudo iptables -I INPUT -p tcp --dport 3930 -j ACCEPT
sudo iptables -I INPUT -p tcp --dport 110 -j ACCEPT #POP3
sudo iptables -I INPUT -p tcp --dport 143 -j ACCEPT #IMAP
sudo iptables -I INPUT -p tcp --dport 993 -j ACCEPT #IMAPS
sudo iptables -I INPUT -p tcp --dport 389 -j ACCEPT #LDAP
sudo iptables -I INPUT -p tcp --dport 995 -j ACCEPT #POP3S
sudo iptables -I INPUT -p tcp --dport 7025 -j ACCEPT
sudo iptables -I INPUT -p tcp --dport 5800 -j ACCEPT
sudo iptables -I INPUT -p tcp --dport 5900 -j ACCEPT
sudo iptables -I INPUT -p tcp --dport 7071 -j ACCEPT #Port for ZCS Web Administration
sudo iptables -I INPUT -p tcp --dport 3894 -j ACCEPT
sudo iptables -I INPUT -p tcp --dport 3895 -j ACCEPT
sudo iptables -I INPUT -p tcp --dport 80 -j ACCEPT #HTTP (for webmail) 

• Fix the hosts file.

vim /etc/hosts

Put the name of the machine (i.e. mail.test-example.com) in the hosts file (assuming that the IP of the machine is 10.0.0.253):

10.0.0.253    mail.test-example.com mail

The hosts file should look like this:

127.0.0.1    localhost localhost.localdomain localhost4 localhost4.localdomain4
::1          localhost localhost.localdomain localhost6 localhost6.localdomain6
10.0.0.253   mail.test-example.com mail

Install ZCS

• Deflate the installation archive (in this case zcs-7.1.3_GA_3346.RHEL6_64.20110928134428.tgz file).

tar -zxvf zcs-7.1.3_GA_3346.RHEL6_64.20110928134428.tgz

• Start the installation:

cd zcs-7.1.3_GA_3346.RHEL6_64.20110928134428
./install.sh --platform-override

• You’ll be asked various questions during the installation, use the default or obvious answers.
• Before completing the installation and writing configuration parameters to the configuration file, you’ll be prompted to review the settings or to fix some unset configuration. At this step, make sure you set the password for the admin user. It has a menu based approach. After reviewing/setting configuration, get out of the screen and save the configuration.
• Let the installer do the rest of the configuration, at the end of which you will be notified of the completion of the installation.

Access Zimbra Collaboration Server

The default location of ZCS installation is /opt/zimbra/, and the installer configures a init.d/service script through which you can stop, start, restart and check the status of ZCS. All zimbra components and daemons run as user zimbra. ZCS Administrative web-interface is available at 7071 port and the webmail runs at the default http port (i.e. port 80) of the machine. For this instance, the administrative interface would be available at http://mail.test-example.com:7071 and the webmail would be available at http://mail.test-example.com.