Category Archives: Email Delivery

Why are my messages not getting delivered?

Unless you’re an IT professional, you might not understand the ins and outs of email delivery. As your business continues to grow, it’s important to ensure your messages are delivered as planned to the intended inboxes. For companies that rely on email correspondence to expand their brand, knowing the intricacies of email delivery is a necessity. MxToolbox is your expert on an often-overlooked aspect of electronic communication deliverability: functioning SPF and DKIM.

Importance of SPF and DKIM

For your email delivery rates to be as high as possible, your first need to keep your sending IP addresses off of blacklists.  Now, correctly implementing Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) is crucial to email delivery. The SPF protocol is an email validation method designed to limit spoofing. SPF allows you to publish a list of IP addresses that are authorized to send on behalf of your domain.  Receiving mail exchanges verify that incoming mail sent from a domain comes from an IP address authorized by that domain’s administrators.  Major inbox providers, like Gmail, Yahoo! and, scan email to validate that the sending IP is included a sender’s SPF record.  If not, the email can be rejected.

DKIM allows a sender to cryptographically sign an email, essentially claiming ownership.  DKIM also helps to combat spoofing.  When a recipient inbox provider receives an email, they can check the signature against a public key published by the sender.  If everything checks out, then the inbox provider knows the sender authorized the email.  Failed emails may be rejected.

By keeping an updated list of active outbound domains/providers that your company uses to send messages, you will be practicing good email hygiene.  You are removing one of the key reasons email is rejected – senders not listed in your SPF records.  Knowing which senders are and are not utilized creates a more organized approach to email deliverability and enables you to configure SPF and DKIM more accurately.  In addition, you cannot ignore the importance of monitoring your IP blacklist reputation.

If you accidentally misconfigure your SPF and/or DKIM protocols, your messages may be quarantined or outright rejected by inbound providers.  Incomplete/erroneous records, new senders missing from SPF implementation, and providers not handling DKIM properly are just a few of the issues that could derail your email delivery efforts if the SPF/DKIM mechanisms aren’t correctly applied. Identifying and resolving these issues equates to a simplified workload for inboxes to recognize your emails are legit and they come from a trusted domain.

MxToolbox is the Email Delivery Expert

MxToolbox provides everything you need to curate your outbound email provider list, analyze your email reputation, and setup SPF, DKIM and DMARC moving forward.  With a variety of insightful and comprehensive products available, MxToolbox is the clear choice to address your email delivery needs. Contact our experienced team to discuss how to best maximize your message delivery rates and expand your company’s brand.

Email Deliverability

Email deliverability should be a concern for any business. If you cannot effectively reach your customer base, you cannot do business.  Your business needs to ensure your email systems (both 3rd party & internal) are:

  • Operational
  • Properly configured
  • Free of negative reputation issues
  • Listed in your SPF record
  • Support DKIM
  • DMARC compliant

Additionally your business needs to be safeguarded against online phishing and spoofing campaigns that mimic your business and diminish trust in emails sent from your business. To help you achieve optimal delivery rates, detect email system & configuration issues, and prevent fraudsters from tarnishing your brand, MxToolbox offers several beneficial tools.

Today, we’ll focus on the Email Deliverability tool.  Email Deliverability provides your company a full report assessing your overall delivery status, combining many diagnostic email delivery and reputation tests into one tool.

MxToolbox’s Email Deliverability Tool

This specific tool allows you to receive a comprehensive message deliverability report in two quick steps.

  • Step 1: Send a test email to from the email system you want to test
  • Step 2: Once you’ve sent an email, you’ll receive an email from us giving you a quick snapshot of your report, simply click the “View your full deliverability report” link to access the detailed feedback. You can additionally just enter the email address that sent the message in the input field on the Email Deliverability tool page.

The Report

MxToolbox systems analyze your headers, the blacklist reputation of your outbound IP address, and tests your email to verify SPF, DKIM, & DMARC authentication pass. Thanks to a recent update, the free Email Deliverability tool now delivers SPF & DKIM verification to ensure the email is being properly authenticated. You would be surprised knowing how many senders have SPF & DKIM issues affecting their email delivery and the reputation their email environment. By providing vital data about your email status, this tool shows where your company’s email platform needs help.

Adding to the list of the Email Deliverability Tool benefits, you can test your business messages for blacklists, as well as DMARC, SPF, and DKIM errors.

Protecting your brand with DMARC

Let’s envision a potential nightmare for your brand:  Your database gets hacked and all of your customers’ private information is now on the dark web, potentially available to exploit.  Now, you need to notify all of your customers to the potential threat.  Instead of sending it out through your typical email channels, you decide to setup a special domain specifically for this purpose.  Sounds logical, right?  What could go wrong?

How about the rejection of this highly important email and a serious erosion of trust for your brand?

If this sounds far-fetched, it shouldn’t.  It really happened to a Fortune 500 brand in 2018 – Marriott.

The Full Story

Following a harmful data breach involving personal information of up to 500 million guests in late November of 2018, the hotel giant decided to send notifications to its customers using a new domain, instead of or, the affected brands.  Traditionally, Marriott properties had used the domain of the brand for customer communications around reservations, for example for Courtyard by Marriott properties.

From a technology standpoint, this was a completely logical decision. Marriott had been transitioning email communications to the domain for sometime.  However,  customers reacted with confusion for several reasons:

  1. The message sender name appeared to be email-marriott, not Marriott, or an identifiable brand.
  2. looks strange to customers of other Marriott brands that may not use the Marriott name: Starwood, Westin and Ritz-Carlton for example.
  3. It is a common technique for spoofers to use a domain that uses similar names to the intended target.
  4. The topic of the message is about security, which automatically heightens customer attention to small details relating to security.

Missteps by Marriott

Not only did it backfire in terms of reaching the inboxes of their client base, it also created a major backlash and critically damaged their email reputation.  Particularly troubling is item #3, the domain mimics a fraudster’s spoofing/phishing efforts, some receivers were undoubtedly leery of opening the message. Appending common words to a known brand name is a scammer’s go-to move. The following phishing domains have been used in recent cybercrime attempts:


Marriott’s failed to recognize the potential pitfalls of their notification strategy and ended up compounding a customer relations problem.

What’s in a Domain?

Your company’s email reputation, as well as your customers’ security and trust in your brand, rely on which domain you utilize. Selecting an identifiable sender domain name is a best practice for businesses that rely on email to regularly communicate with clients. Domain name reputation plays a vital role in email deliverability. Unfortunately, Marriott discovered the hard way that using a nonspecific domain to suddenly send hundreds of millions of emails isn’t a good idea.

Building your company’s domain reputation can be achieved in several ways, including the length of time the domain has been registered and using it to send messages to engaged recipients. Having legitimate contact information listed on your website also helps increase overall reputation and deliverability.

Protect Your Brand

Because online security is a legitimate concern for your customers, making sure all outgoing emails are safeguarded and delivered as intended should be a top priority for your business. At MxToolbox, we specialize in helping you achieve high message delivery rates. By improving your company’s domain reputation, situations such as the aforementioned Marriott fiasco will be of no concern. To discuss your brand’s options and learn about MxToolbox’s DMARC products to solidify domain reputation, please contact our team of experts. We look forward to helping you achieve future email success.

New Features for MxToolbox

At MxToolbox, we’re continuously striving to provide cutting-edge tools to help our customers improve their company’s email practice. As you can see on our Network Tools page, we offer a wide-range of helpful free tools and paid products that ensure your business email platform is working at its optimal level. And since we’re routinely updating and expanding our collection of tools, we recommend you visit the page often for the latest developments. For the most recent updates and newest tools please check out the NEW! tab. Let’s take a closer look at some of the more popular MxToolbox features.


Email Tab

The email portion of the Network Tools page contains some of our most popular tools such as the MX Lookup and Blacklist Check; and offers several other essential diagnostic tools that can greatly benefit your company’s email setup. For example, the SPF, DKIM, and DMARC tools now support improved message delivery and provide feedback catered to your business domain. Moreover, the two specific DNS record generators features (SPF and DMARC) MxToolbox offers under this tab help create records for the respective protocols.

Network Tab

For this section of Network Tools, the ASN Lookup and Domain Health Report tools are highlighted points. For example, the ASN (Autonomous System Number) Lookup query takes either an AS name or AS number as input and returns the missing component. For immediate feedback regarding your domain, the Domain Health Check will execute hundreds of domain/email/network performance tests to ensure your systems are online and performing optimally. In addition, the report will provide results for your company’s domain and highlight any critical problem areas that need attention.


The DNS tab provides all the key DNS tools to help make sure your DNS records are published correctly and your DNS is operating at 100% such as DNS Lookup, DNS Check, and Whois. This list of tools also contains some advanced DNS Security diagnostic tools such as nsec, rrsig, and more.

MxToolbox’s Newest Additions and Updates

Among the many email tools MxToolbox offers, there are a few that stand out. Although we love each equally, if forced to name favorites, these come to mind:

  • DMARC Report Analyzer – One of our newest tools, this feature will make DMARC Aggregate XML reports human readable by parsing and sorting them by IP address into understandable reports.
  • DMARC Generator – Another new tool we’re proud of, this generator will help you create a DMARC record specifically for the domain/subdomain that you submit. Simply put, this tool’s a must for your DMARC implementation.
  • Header Analyzer – Found under the Email tab, this tool will make email headers human readable by parsing them. This helpful feature is a popular tool to which we’ve recently added DMARC, SPF, and DKIM testing functionality.
  • Email Deliverability – Also under the Email tab umbrella, this tool has been updated for easy workability. Send a test email to us, and we take over from there to generate a comprehensive deliverability report. To receive crucial data regarding your email status, definitely try this tool.

MxToolbox strives to provide your business the most beneficial information related to your email platform. By offering your company a variety of free tools to gain optimal deliverability, we believe our tools allow your messages to be delivered successfully. This not only protects your business, but also your customers. Whether found under one or more tabs, the features shown on the Network Tools page are vital to your email rates. Be sure to explore the page and try as many as desired. We’re here to help.

Can DMARC stop spam?

Yes, yes it can.  But, how?

DMARC, by itself, does not stop a spammer from sending email.  To be effective at reducing spam, everyone needs to implement DMARC and follow-up by improving the compliance rates of their outbound emails.  As your legitimate email becomes more DMARC compliant, you can begin to tell recipients to ignore email that isn’t compliant.  This spam will bounce and foil the spammers trying to use your brand!

Learn More about how MxToolbox can help you.

Why do blacklisting and DMARC work together?

Your email might have been blacklisted at one time.  You probably found that out when customers or suppliers told you that they weren’t receiving email they were expecting from you.  It’s painful and can shutdown your business.  Staying off blacklists is just one of the ways to guard your email deliverability.  The other is DMARC.  DMARC enables you to proactively obtain feedback about your email so that you know about how your recipients’ email systems perceive your email quality.  From that information, you can determine how to improve your email quality before it becomes a blacklisting issue.

Learn More

Prevent Spoofing with DMARC

Have you received an email that looks like it comes from your bank, credit card company or a retailer only to find out that it was fake?  Has anyone used your company’s brand to send a similar spoofed or fraud email?

Spoofing has become commonplace, even for small companies.  In fact, one of our customers found that their spoofed email volume was 3 times the amount of legitimate email.  At that rate, companies have no choice but to reject your email, assuming that all email “from” your domain is spam or fraud.

DMARC can help you prevent your domain from being spoofed,  and MxToolbox can help you understand DMARC.  Learn More