Deliverability Drilldown: B2B Corporate Email Systems

This is part of our ongoing series looking at deliverability of your email marketing messages.

Today, we’re going to look at arguably the most complex of deliverability areas, the corporate email domain. It’s complex because unlike B2C email marketing, B2B email marketing has the most varied deliverability challenges. Some companies use hosted services like Google Apps that are powered by Postini, a cloud-based service. Some companies have ancient Microsoft Exchange servers that haven’t been substantially updated in a decade. Others have dedicated appliances like Barracuda or free Bayesian filtering systems like SpamAssassin.

All of this adds up to a complex stew of deliverability issues for B2B marketers.

Basics of B2B Corporate Email Systems

As with all forms of email marketing, your first and safest bet is to only send email to people who’ve asked to receive it. That never changes. Let’s look at what’s beyond that.

In the B2B email marketing world, there are fundamentally 3 types of anti-spam systems: integrated, cloud-based, and appliance. Integrated spam filtering systems are built into corporate mail servers, such as SpamAssassin or Microsoft Forefront. Cloud-based SaaS services provide spam filtering before it reaches corporate mail servers, with services like Cloudmark and Postini. Finally, appliances are actual mail filtering servers that sit on-premise in a customer’s location.

How does this impact deliverability? One of the issues with any on-premise solution is that maintenance and upkeep is required, which companies tend to defer for as long as possible. Thus, spam best practices that are now obsolete, like content-based filtering, are still in use by these older systems.

Let’s look at the basics of B2B email deliverability.

1. Remove bad addresses immediately. While having bad addresses on your list is generally a bad idea, it’s particularly harmful for B2B systems. As soon as an address goes bad, flush it out of your list. There’s more harm than help in keeping them around.

2. Avoid role emails in your list subscriptions. Many corporate systems automatically flag email sent to role-based email addresses like or Put some filtering options in place on your subscription forms that ask for a different address.

3. To work well with cloud-based corporate spam filtering, make sure you’re set up with DKIM and SPF/Sender ID. WhatCounts customers did this in your on-boarding process.

Advanced B2B Mail Deliverability

Unlike B2C email systems such as Hotmail or Yahoo, corporate email systems have much stricter thresholds for how much mail you’re allowed to send at any given time. If you’ve got a list that’s got a tremendous number of addresses from any one corporate domain, consider using throttling when you send your mail to rate-limit how much mail you dump onto any one server at a time.

Professional Edition users will find this under Advanced Settings during a Deploy Campaign send:

Deploy Campaign - corporate email systems

Publicaster Edition users will find this under Metered Send:

B2B Corporate Email Systems

For corporate email systems using SpamAssassin and other filtering, you’ll want to spend some time reading through the SpamAssassin rules (they’re quite extensive) to see what things the system looks for. Here’s just a sample of some of them:


Finally, if a particular email domain is vitally important to you or your business, make sure to take the time to develop a relationship with their IT administrator if you run into problems. Many of them will respond to questions or complaints if you email them, and most operate a working or address. Be courteous, be forthright about why you’re sending, and be ready to show proof of subscription for users of that domain. If you’re a WhatCounts client, ask your account manager for help and we may be able to provide additional assistance in your outreach.

We hope this deliverability drilldown into B2B email deliverability has provided you with some immediately usable insights to help your email marketing program flourish. If your current email service provider is unable to assist you with any of these delivery to-dos, please feel free to contact WhatCounts.

Christopher S. Penn
Director of Inbound Marketing, WhatCounts


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6 Responses to "Deliverability Drilldown: B2B Corporate Email Systems"
  1. Tim Brechlin says:

    One note … Google is shutting down Postini and merging its functions into Google Apps, so we don’t know right now if that’s going to mean another shift in its deliverability algorithms (since we all know how much Google likes to change its algorithms).

  2. Kent McGovern says:

    Don’t forget that a lot of businesses have their email hosted through the normal B2C heavy weights such as Yahoo and Hotmail. So you will always be dealing with those providers one way or another.

  3. Dorian Wagner says:

    Some of those SpamAssassin rules are hysterical!

  4. Shonika Proctor says:

    SendGrid offers a great solution on the backend for app developers whose apps are getting lost in corporate email systems. Their solution basically eliminates the need for forgetting all the server management/sacling/spam related issues.

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