Identifying Legitimate Emailers

Email management has become more complicated over the last few years.  It used to be that only IT could setup email services for a company.  Now, almost anyone can setup email services on behalf of an organization.  Increasingly often, Marketing, Sales and other organizations are subscribing to SaaS services like Marketing Automation, CRMs, Bulk Emailers, etc that often send email for these organizations to customers, vendors, partners and suppliers.  If not properly managed, you can lose control of your legitimate email and cause email delivery problems that impact your business.

How do you Identify Legitimate Emailers?

First, you need to adopt two important technologies: SPF and DMARC.  SPF allows you to designate IP addresses and domains that can send on behalf of your domain.  Add all your known providers to your SPF record to ensure email from those providers is properly received and processed by inbox providers.  You can find out more information about SPF and how to create SPF records on our site.  DMARC enables you elicit information from inbox providers on how email send on behalf of your domain is being received and processed.  This will contain data on both legitimate and illegitimate senders like fraud and phishing.  MxToolbox provides DMARC configuration and validation tools.

The second step to identifying missing legitimate providers is to start reading the digests inbox providers send to your DMARC response address.  To do this, you’ll either need some skill with reading XML and a lot of patience or a service that consolidates, processes and analyzes DMARC digests from inbox providers.  The larger your email volume, including illegitimate email, the harder it is for you to process these digest by hand.

Examine unknown

Delivery Center differentiates emailers in your SPF and those potentially illegitimate senders.

MxToolbox has developed a product to help businesses like yours analyze DMARC compliance and responses to improve your email configuration, email deliverability and your online brand reputation.  MxToolbox Delivery Center gives you instant access to statistics on email delivery and email reputation including all the IP addresses and domains sending on your behalf.  Tools like Delivery Center are the best way to find legitimate senders not in your SPF records.

The last step to identifying unknown legitimate emailers, once your SPF and DMARC records are setup and delivering digests to your choice of tool, is to examine who is sending on your behalf.  Tools like Delivery Center show statistics about SPF Authentication, SPF Alignment, and DMARC compliance.  Emails that pass these checks are more likely to reach your customers inboxes.  Emails that fail are more likely to be tossed into junk folders or bounce entirely.  Looking at sending IP addresses and domains can give you insight into potential legitimate senders that you may have missed in your SPF records and the potential for fraud and phishing emails from senders posing as you.

To identify Legitimate Senders:

  1. Review the largest volume senders that fail SPF, DKIM and DMARC
  2. Investigate the Domains and reverse DNS of the IP addresses – Do they look like legitimate email providers?  Legitimate providers own a number of IP addresses, have a website that shows off their products and pricing.  These could also be legitimate email forwarders, even if you are not specifically doing business with them.
  3. Investigate the Blacklist reputation of IP addresses and domains – Are they blacklisted?  Legitimate providers may have a small portion of their network blacklisted as part of their business but if a large portion of that network is blacklisted they may not be a good provider to use or may be shady.
  4. Investigate the location of the IP addresses or ASNs – Are they sending from a country that you don’t operate in?  Are they sending from a country with known hacking issues?
  5. Slice and dice the data – No single view will give you every angle.  Looking up DKIM domains or SPF domains, sender domains or Mail From headers can give you insight.  The trick is to have a tool that enables you to review your DMARC digests from all angles.
  6. Be patient and repeat often – You won’t solve your email delivery issues in a single day or a single pass.  This is something that you need to review on a regular basis, especially since you may be adding or changing legitimate senders frequently.

MxToolbox Delivery Center gives you access to compliance and authentication information with multiple views to give you the best insight into your email delivery.


DMARC is the key to improving Email Deliverability!

Email is the key to your customer communication strategy.  But, what is your email reputation?

Setting up and managing your DMARC configuration is the key to getting insight into your email delivery.  MxToolbox is the key to understanding DMARC.

MxToolbox Delivery Center gives you:

  • Who is sending phishing email purporting to be from your domain
  • What is the reputation of your domains and delegated IPs
  • Where other senders are and What their reputations are
  • How your SPF, DKIM and DMARC setup is performing

Learn More

Source: MXtoolbox