Email Domain Reputation Guide: How to Check Domain Reputation & 5 Tips to Improve Domain Reputation

Estimated reading time: 14 minutes

Sending an email may look simple: write the text, add a catchy subject line, choose your recipients, click “Send”, and you’re done. In an ideal world, emails might appear in the recipients’ Inboxes every time, but in this one, things are a little trickier. 

According to the latest email deliverability statistics calculated based on the GlockApps tests, 33% of emails on average appear in the users’ Spam folders and every third message is never delivered. In reality, it takes meticulous preparation and work to send and deliver emails successfully. 

In this article, we concentrate on email domain reputation, which is a crucial component that affects whether your emails end up in the Inbox or Spam.

What is Email Domain Reputation?

An email domain reputation is your credit score with the Internet service providers (ISPs). They utilize your email domain reputation to determine whether your emails are trusted enough to land in the Inbox. ISPs publish email sender guidelines that should be followed by all the senders who want to successfully deliver the messages to the ISP’s users. 

When an email arrives, email filters do a number of checks before letting an email through. You should have no problems if you follow the regulations and have a good reputation. However, if your email reputation has spots, it’s likely that your emails will be filtered out or rejected. 

ISPs frequently reject emails from senders with a history of phishing or spoofing assaults because they are particularly wary of such domains. Because of this, an email domain reputation plays a crucial role in deciding whether your emails are blocked or reach the inbox.

It’s crucial to remember that an email domain reputation is not the same across all of the ISPs. Every mailbox provider has its own unique algorithm of assessing your domain reputation, making it a complex and personalized aspect of email deliverability. 

Thus, the same email sent from the same domain may arrive in AOL Inboxes without any issues, but Gmail may mark it as spam. This suggests that senders should use a more thoughtful and personal approach to email marketing to be able to reach out to their clients using different providers.

What are the Factors Affecting Email Domain Reputation?

Your email domain reputation score is influenced by the data collected by each mailbox provider after the analysis of the emails sent from your domain. The most important factors that make a domain reputation score with the majority of the providers are:

1. Email Volume.

The ISPs need to see a good email volume originating from a domain to assess its reputation. When a new domain is established, it goes with a neutral reputation and needs time to get one. It is crucial to follow a good domain warmup plan to build an email reputation. The more emails are sent, the more accurate the reputation score is.

2. Email Domain Authentication.

Emails sent from a domain without properly configured SPF, DKIM and DMARC records can drastically decrease the domain reputation. Email authentication is mandatory for every legitimate email sender. ISPs want to deliver only good messages to their users and put a lot of weight on email authentication protocols. Thus, the implementation of SPF, DKIM and DMARC authentication protocols is the first step to perform before you send a single message from the domain.

3. Email Bounce Rate.

ISPs closely look at how many messages sent from a domain in one campaign bounced back. There are two types of bounce emails:

• Hard bounce: the messages that were returned to the sender due to a permanent delivery failure in most cases caused by an invalid recipient’s email address.
  
• Soft bounce: the messages that were returned to the sender due to a temporary delivery failure (mailbox is full, sending quota is reached, server is not responding etc.).

Hard bounce emails have a bigger impact on an email domain reputation because they indicate how properly you are managing your email list. Soft bounce email addresses should also be considered as bad if the delivery is not successful after four or five attempts. The ISPs typically allow a small bounce rate per email campaign; if the rate is exceeded, your messages get closer attention. 

4. User Reported Spam Rate.

Each time a recipient clicks the “Mark as Spam” button, it counts as a spam complaint against you. While one complaint might not severely impact your domain reputation, it adds to a cumulative effect. To maintain a good email reputation, you have to keep your spam complaint rate below 0.1%.

5. Unsubscribe Rate.

Unsubscribe rates provide valuable insight into your audience’s engagement and allow ISPs to understand whether or not you are sending relevant messages. Ideally, you should aim to keep the unsubscribe rate per campaign at or below 0.5%. High unsubscribe rates may lead to a stronger spam filtering and a lower email reputation score.

6. Spam Traps.

Email addresses used specifically to identify spammers are called spam traps, or honeypots. There are two main categories of them:

• Pristine spam traps: these email addresses have never been used by a real person; they were set up by ISPs and anti-spam organizations deliberately to identify malicious senders. Emails sent to these addresses give ISPs the impression that your list building strategies might not be trustworthy.

• Recycled spam traps: these email addresses were formerly legitimate but are now inactive. They are used by ISPs to assess whether your email list is clean. Even while these spam traps aren’t as bad as pristine spam traps, they might nevertheless have a detrimental impact on your email domain reputation.

7. Blacklists.

Blacklists are the databases storing the IP addresses and domains known to send spam. The most notable ones are Barracuda, SpamCop, and Spamhaus. Your email deliverability and email domain reputation could be seriously harmed by being included on one of these.

Additionally, there are other signals – sometimes overlooked by the senders – that may be more or less evaluated by the ISPs to calculate a domain reputation score. These factors may include:

8. Recipient Engagement

Engagement rates are a key measure of your audience’s interest in your emails. They are based on two primary metrics: 

• Open rate: the percentage of the recipients who opened your email.
• Link click rate: the percentage of the recipients who clicked on links in your email. 

A high open rate shows that your audience is actively reading your emails and that your subject lines are attention grabbing. A high click rate shows that your email content and call-to-actions are interesting and valuable. High engagement rates work for your domain reputation confirming that your emails are welcomed and worth landing in the recipients’ Inboxes.

9. Email Volume Consistency

The subscriber base of legitimate marketers usually grows steadily, which causes the volume of emails sent to rise gradually and steadily. Sudden increases in email volume and inconsistent sending frequency, however, may raise red flags and damage your domain reputation. Email marketing is about finding a good balance of the email volume and frequency. 

10. Email Domain Age 

A domain age may be taken into consideration by the mailbox providers when assessing the email reputation and the reliability of the messages. Aged domains with a good sending history may show higher deliverability rates versus young domains.

How to Check Email Domain Reputation

As your email domain reputation directly impacts deliverability of your email campaigns, it’s important to be aware of how different providers score your sender reputation. It becomes even more vital when you start seeing your email open rates and response rates decrease. There are various online tools out there that you can use to check your email reputation:

1. GlockApps

GlockApps is an online email deliverability testing service that provides valuable information about your sending infrastructure and email placement. After running a seed-based email test, you get a detailed report that includes:

• Inbox, Tabs, Spam, and Missing ratios;
• IP analytics: blacklisting status of the sending IP address;
• Domain analytics: blacklisting status of the sender’s domain;
• Authentication: HELO to IP, rDNS, DKIM, and SPF;
• Spam score: email spam scores given by Google Spam filter, Barracuda, and SpamAssassin;
• Email placement: real placement of the message with various ISPs across the world;
• HTML support: how your email’s HTML code is rendered by different email clients and devices;
• Action steps: troubleshooting tips created by the system after analyzing your email configuration and message.

Investigating the GlockApps reports, you can find out which ISPs repeatedly send your emails to Spam – which is most likely determined by a low email reputation with those ISPs. 

GlockApps Postmaster allows you to easily get the domain reputation data from Google Postmaster in your account.

2. Google Postmaster

A free tool called Google Postmaster Tools is intended to give you comprehensive information about the reputation of your IP and domain. Additionally, it provides important metrics for email authentication, encrypted traffic, spam rate, and delivery errors. 

You need to add your domain to Google Postmaster and verify your ownership by adding a TXT record to the domain’s DNS before you can access your domain’s reputation data. It is to note that Google Postmaster will assess and present the data if it sees a certain number of emails sent from the domain (at least 100 emails/day) to Gmail and Google Workspace users. 

3. MXToolbox

MXToolbox is an excellent tool for evaluating the reputation of your domain. It runs a diagnostic check of your domain to find any blacklist entries that can harm your reputation. Its user-friendly layout and ease of use has made it a reliable resource for domain owners.

4. BarracudaCentral

Unlike other tools that check domains against public blacklists, BarracudaCentral has its own database of IP addresses and domains that have “poor” reputation. The reputation assigned to an IP or domain by the Barracuda Reputation system impacts only the messages sent to the mail servers that have the Barracuda filtering in place. However, it can still be quite helpful to use Barracuda to perform a domain reputation lookup and ensure that your deliverability is not affected by “poor” URIs.

5. Sender Score

Sender Score by Validity checks an IP or domain reputation in real-time providing the result as a score between 0 and 100. It retrieves DNS records, analyzes your domain to determine who owns it, and uses SSL certificates to confirm website ownership. High reputations are assigned the scores between 80 and 100. The tool will also show the factors that are taken into account when calculating an IP or domain reputation score and their impact on your sender score.

6. Talos Intelligence

Talos Intelligence by Cisco provides a thorough evaluation of your IP and domain reputation. With the help of this tool, you can get real-time data about the IP’s or domain’s owner, mail server, reputation, and listing on Talos Intelligence blocklist.

How to Improve Email Domain Reputation

Improving a low domain reputation can be a challenge, but with the right approach, it’s entirely possible. By implementing email list management best practices and building a robust email infrastructure, you can steadily improve your email reputation and deliverability. Here’s what to consider:

1. Email Authentication

It’s mandatory to have the authentication protocols such as SPF, DKIM and DMARC  put into place for a sending domain. These protocols work together to provide a strong basis for a strong domain reputation and protection. 

To help senders receive the information about email authentication outcomes, the DMARC protocol allows email receivers to send DMARC reports to the domain owner. The reports contain valuable information about sending IPs, authentication failures, and email volume. 

There are tools like GlockApps DMARC Analytics that receive and process DMARC reports automatically providing senders with helpful insights and analytics on how their domains are being used.

2. Subdomains for Different Email Flows

Your main domain can be extended with subdomains to improve segmentation and organization of your email streams. For example, you may utilize subdomains like @info.domain.com, @support.domain.com, or @email.domain.com if your primary domain is @domain.com.

You can use separate subdomains for different kinds of campaigns. For instance, you can use one subdomain for marketing campaigns and another for transactional emails.

How does it help? It protects the reputation of your main domain where your website is hosted. Although the reputation of a subdomain can affect the reputation of your primary domain, this effect is usually minimal. Furthermore, there is greater flexibility and control because the reputation of one subdomain has no influence on others. Even in the event of spam complaints, you may maintain high delivery rates and protect the reputation of your primary domain by utilizing subdomains.

3. Domain Warmup 

Internet Service Providers tend to be wary of new senders. Without an established reputation, they scrutinize the messages sent from new domains and IPs more carefully.

To overcome this, it’s essential to warm up your IPs and domains by starting with small volumes of email and gradually increasing the sending rate over time. Every new subdomain you set up for email sending should be warmed up.

4. Email List Hygiene

Maintaining a clean mailing list is just as vital as growing it naturally. To reduce the likelihood of spam complaints, do not ignore the best list management practices:  

• Use double opt-in. This procedure ensures that your subscribers actually want to receive your emails and allows you to avoid getting spam traps, invalid addresses, and bot subscriptions on your list.
• Remove hard bounces. Exclude the email addresses that produce hard bounce messages. If you are using an email service provider, they will most likely handle this for you.
• Do not send to unsubscribed users. Honor unsubscribe requests in a timely manner and ensure no further messages are sent to these people. 
• Process spam complaints. A spam complaint is sent when a recipient reports your message as spam. Spam complaints are handled by the Feedback loop (FBL) services provided by the ISPs. A notification about a user reported spam is typically sent back to the sender if you sign up for the FBL service. Reputable email service providers handle feedback loop messages for their clients and automatically exclude the recipients who reported the email as spam from an active mailing list.
• Remove inactive users. Keep an eye on recipient engagement data on a regular basis. Consider deleting a subscriber from your list if they haven’t opened your emails within the last 3-6 months. This proactive approach lowers the possibility of hitting spam traps while maintaining a healthy and active subscriber list.

5. Segmentation and Personalization

Sending content that reflects the interests of your audience is vital. Thoughtful segmentation can bring increased open and response rates and minimize spam complaints harming your email domain reputation. Here are some ideas on how you can segment your list for sending more personalized and targeted email campaigns:

• Segment by interest. It’s important to give your subscribers valuable content they subscribed for. Thus, if they subscribed to your blog updates or weekly newsletters, they’ll probably hit the unsubscribe button if you start sending irrelevant material.
• Segment by engagement. Track your open rates to see who hasn’t opened any of your messages during the last 3 months. You may want to prepare a special re-engagement email for the inactive users in an attempt to re-instate their interest.
• Segment by provider. Test your deliverability to see which ISPs place your email in Spam. You may need to create a different, better optimized, version of your message for the problematic ISPs in order to deliver your messages to the subscribers’ Inboxes.

Conclusion

Your email domain reputation stands as a major factor that determines the email placement in the user’s mailbox. Emails sent from domains with a high reputation are most likely to land in the Inbox while the messages sent from “poor” domains are typically filtered out or blocked. 

Each mailbox provider uses its own number of signals to assess a domain reputation. The factors that all the ISPs evaluate include email volume, user reported spam rate, bounce rate, email authentication, and user engagement.  

It’s important to slowly build an email domain reputation by progressively raising email volumes. In order to safeguard the reputation of the domain, carefully control your list management and sending habits to ensure the compliance with the sender guidelines published by ISPs. 

There are various tools that check a domain reputation providing you with instant reports about the domain blacklisting status and your email placement across different mailbox providers. It’s highly important that you monitor your email domain reputation and deliverability to ensure that your subscribers receive updates from you in their Inboxes instead of junk folders.