Email Marketing on a Shoestring

Many ESPs boast that they can’t be beaten when it comes to mass emailing. However, it is essential to remember that sending emails doesn’t have to cost anything and that, with the proper knowledge, you can even send a large number of emails at once reliably and with high deliverability. So, instead of giving in to the ESPs and paying their astronomical prices, we should give it a shot ourselves. To learn more, check out NitroMail

When properly configured, Ubuntu Server and Postfix may readily compete with the service of an ESP for sending large volumes of email. It is feasible to send tens of thousands of emails every hour, even with a residential 8MB ADSL connection. In this piece, I’ll show you how to do it cheaply and easily. This is not a handbook for complete novices so I won’t go into specifics, but you’ll get a good sense of how my incredibly effective model works.

It would be best if you first found an Internet service provider (ISP) willing to provide many static IP addresses. For about $42 per month (including ADSL), BeThere provides 16 static IP addresses. There is one primary IP assigned to your account and fifteen secondary ones. You’ll also require a dependable router to manage several DMZs; the Draytek Vigor 2820 is an excellent choice.

The main component of this design is a high-powered server running VMWare ESXi as a host for several virtual machines. There are 11 Ubuntu Servers hosted on this system, each requiring only the bare minimum in memory (256MB) and storage space (8GB) (10 dedicated Postfix emailing servers, one dedicated DNS server).

Every virtual machine is assigned a static IP address (192.168.1.10–192.168.1.21), and each Postfix server is isolated in its virtual private network (virtual DMZ). As a result, you’ll have access to 10 separate mailing servers, each of which uses its external IP address (e.g., 84.252.220.200-84.252.220.210). So, first, create A record for each IP address in your company’s domain (e.g., email1.domain.com points to IP address 84.252.220.200, email2.domain.com points to IP address 84.252.220.201, etc.).

Then, have your Internet service provider’s DNS staff set up the appropriate reverse IP mapping (84.252.220.200 to email1.domain.com, etc.). Finally, ensure your domain’s DNS server has an SPF record by utilizing the openspf project website (you may need to ask your domain host if possible).

Get the ESXi server license key by registering on the VMWare website after downloading ESXi. If your computer is compatible, setting it up is a breeze. First, create an Ubuntu virtual machine (VM) using the default settings (email1.domain.com, for example) and then install Postfix with the default settings.

DomainKeys/DKIM and a static IP address can be set up, and the public key can be exported to the domain’s DNS server. Then, using telnet from the Linux terminal, you may verify your ability to send DomainKeys/DKIM-signed and SPF-authenticated emails. The Ubuntu community guidelines are invaluable for navigating the sometimes-tricky process of smoothly getting everything to work together.

When you’re ready to test, Google Mail is an excellent tool for inspecting an email’s complete source and confirming details like the sender’s IP address (e.g., 84.252.220.200), the sender’s domain name (email1.domain.com), whether the DomainKeys/DKIM signature was successful, and whether or not your SPF record was correctly configured.

Gmail with working SPF, DKIM, and DomainKeys

Congratulations! You can now use your own personal Ubuntu Postfix email server. Now, spin up a second virtual Ubuntu server and install BIND; this machine will function as the specialized DNS server (you may call it emails, for example). Use nslookup to verify the effectiveness of your forward lookup settings (I recommend OpenDNS). If you have a dedicated server for sending emails (called email1 or something similar), you should change its DNS settings to emails. To prevent our network from being slowed down by unnecessary DNS lookups, we want all of our Ubuntu Postfix email servers to direct their queries here.

After verifying proper operation, you can clone the virtual machine by manually installing it nine more times or by shutting down email1 and copying the files nine times. There are complications with cloning virtual machines, such as duplicating network interface cards, but setting up additional email servers is a breeze if the first one is up and running. Make sure everyone is using the same private DomainKeys/DKIM key!

When you’re done, you’ll have ten independent Ubuntu Postfix servers, each with its external IP address and eager to send your mail. In addition, campaign Enterprise and email marketing tools can be easily configured to send from up to ten SMTP servers.

Resulting In

Ten separate Ubuntu Postfix email servers have been set up, each with its external IP address (and hostname) configured to query the same DNS server.

What’s even better? With this strategy, I can obtain deliverability rates similar to those seen in the industry at no cost (apart from the server and ADSL contract). Even more recently, Return Path called to see if they could assist. Unfortunately, after reviewing my data, they told me they could not help me.

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