How to block email from a specific address on a cPanel/WHM or other web server using Exim

With EXIM, you can setup filters that can perform a large number of tasks, like blocking message, or blind copying messages to other email addresses.  In this case, I’m going to create a filter to cause an email coming from a specific sender to fail (the email address I use to send the email in PHP). What you’ll want to do is find your System Filter File for EXIM.  In WHM, you can find this file listed in your EXIM Configuration Editor about half way down the page. Once you’ve located the file, log into SSH and edit the file.

pico /path/to/your/file

Then enter the following filter into the file and save it:

if first_delivery
and ( ("$h_from:" contains "emailtoblock@mydomain.com")
)
then fail
endif

If you’d like a copy of the email sent to you after the message fails so you can make sure it is correctly formatted, just add one line:

if first_delivery
and ( ("$h_from:" contains "emailtoblock@mydomain.com")
)
then
unseen deliver "youremail@yourdomain.com"
fail
endif

I suggest you read up more about EXIM filtering for more advanced functions. Where I Learned This: I found the solution the Imthiaz Blog and the Exim Documentation.

Exim Configuration Manager:basic editor

There will be a warning in Filter configuration File: /etc/cpanel_exim_system_filter

Exim filter
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#  cPanel System Filter for EXIM                                                                                #
#  VERSION = 2.0                                                                                                #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#   !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!DO NOT MODIFY THIS FILE DIRECTLY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!      #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#   Direct modifications to the /etc/cpanel_exim_system_filter file will be lost when the configuration is      #
#   next rebuilt. To have modifications retained, please use one of the following options:                      #
#                                                                                                               #
#    1)                                                                                                         #
#      * Place each sysfilter block you wish to include in a unique file at:                                    #
#            /usr/local/cpanel/etc/exim/sysfilter/options/                                                      #
#      * Enable or disable the custom block in WHM using:                                                       #
#          Service Configuration => Exim Configuration Manager => Filters => Custom Filter: [your unique file]  #
#                                                                                                               #
#    2)                                                                                                         #
#      * Create a custom sysfilter file in /etc/                                                                #
#      * Change the location of the sysfilter file in WHM using:                                                #
#          Service Configuration => Exim Configuration Manager => Filters => System Filter File                 #
#                                                                                                               #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#   !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!DO NOT MODIFY THIS FILE DIRECTLY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!      #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#                                                                                                               #
#  Only process once                                                                                            #
#                                                                                                               #
# # # # # # # # # # # # # # # # # # # # #

So I created this simple php file on /usr/local/cpanel/etc/exim/sysfilter/options and it was visible in the WHM filter.

SPI (SaaS, PaaS, IaaS) model in cloud

SaaS

Cloud application services or “Software as a Service” (SaaS) are probably the most popular form of cloud computing and are easy to use. SaaS uses the Web to deliver applications that are managed by a third-party vendor and whose interface is accessed on the clients’ side. Most SaaS applications can be run directly from a Web browser, without any downloads or installations required. SaaS eliminates the need to install and run applications on individual computers. With SaaS, it’s easy for enterprises to streamline their maintenance and support, because everything can be managed by vendors: applications, runtime, data, middleware, O/S, virtualization, servers, storage, and networking. Gmail is one famous example of an SaaS mail provider.

PaaS

The most complex of the three, cloud platform services or “Platform as a Service” (PaaS) deliver computational resources through a platform. What developers gain with PaaS is a framework they can build upon to develop or customize applications. PaaS makes the development, testing, and deployment of applications quick, simple, and cost-effective, eliminating the need to buy the underlying layers of hardware and software. One comparison between SaaS vs. PaaS has to do with what aspects must be managed by users, rather than providers: With PaaS, vendors still manage runtime, middleware, O/S, virtualization, servers, storage, and networking, but users manage applications and data.
PaaS provides the computing infrastructure, the hardware, and the platforms that are installed on top of the hardware. Similar to the way that you might create macros in Excel, PaaS allows you to create applications using software components that are controlled by a third-party vendor. PaaS is highly scalable , and users don’t have to worry about platform upgrades or having their site go down during maintenance. Users who benefit most from PaaS include companies who want to increase the effectiveness and interactivity of a large staff. For the needs of larger companies and independent software vendors, Apprenda is one provider of a private cloud PaaS for .NET and Java business-application development and deployment.


IaaS

Cloud infrastructure services, known as “Infrastructure as a Service” (IaaS), deliver computer infrastructure (such as a platform virtualization environment), storage, and networking. Instead of having to purchase software, servers, or network equipment, users can buy these as a fully outsourced service that is usually billed according to the amount of resources consumed. Basically, in exchange for a rental fee, a third party allows you to install a virtual server on their IT infrastructure. Compared to SaaS and PaaS, IaaS users are responsible for managing more: applications, data, runtime, middleware, and O/S. Vendors still manage virtualization, servers, hard drives, storage, and networking. What users gain with IaaS is infrastructure on top of which they can install any required platforms. Users are responsible for updating these if new versions are released.

See some explaining diagrams:

Classification of Cloud service providers