Email Authentication, Sending Reputation

Sender Authorization – EmailLabs Free Configurator

Aleksandra Duło, 5 March 2024

In the realm of email, sender authorization is a powerful tool wielded by local and global providers like Gmail, Yahoo, and AOL to combat spam. Additionally, as an authenticated sender, you can immediately avoid spam filters, enhancing the likelihood of your campaigns successfully reaching recipients’ email inboxes. Moreover, ISPs will mark your email messages as authenticated, helping to build trust between you and your subscribers and ultimately increasing the possibility of your emails being opened.

In summary, sender authorization is a feature in the EmailLabs panel that allows you to authenticate your sending domains. It protects your account from unauthorized use by third parties and is a significant security measure against spoofing, phishing attempts, and having our messages marked as spam. 

Domain Autorization

If you have authorized multiple “From” domains in your EmailLabs panel, each of them will sign “its” messages. This means that emails sent from an address associated with a specific domain will be appropriately signed by that domain.

Domain authorization can be configured in the EmailLabs panel in the Admin > Sender Authorization tab.  

In the subsequent sections of the article, we will guide you on correctly navigating through the configuration process in our administration panel:

  1. Sender Authorization in EmailLabs
  2. Domain “From” Configuration
  3. Subdomain Tracking Configuration
  4. Return-Path Subdomain Configuration
  5. DMARC Record Configuration
  6. Sender Authorization in EmailLabs – Full Documentation

Sender Authorization vs DKIM Key

DKIM, which stands for DomainKeys Identified Mail, is an email message authentication protocol that creates a digital signature used by email providers to verify the email sender’s identity. When authorizing a domain, the EmailLabs system generates a unique record that must be added to the DNS settings of a selected domain. It authorizes a domain and enters the DKIM key, which acts as additional authentication for your mailings. This allows the authorized domain to sign your emails with its DKIM key. 

In essence, sender authentication in EmailLabs involves generating unique records in the panel and adding them to the domain DNS settings.

DKIM – How it Works?

DKIM provides a method for validating the identity of the sending domain, which is associated with the message, through cryptography-based authentication methods. The entire process resembles the asymmetric encryption approach of PGP and operates as follows:

  1. E-mail signing: The email header incorporates a unique DKIM record, which consists of a digital signature that has been generated from a corresponding sender’s private key. This specific signature is crafted using cryptographic algorithms, notably RSA.
  2. Verification by receiving mail server: Upon receiving the message, the server checks whether the sender’s domain has a DKIM record in its DNS configuration.
  3. Signature verification: The receiving server retrieves the public key from the DKIM record located in the sender’s domain DNS and uses it to verify the digital signature contained in the message header. If the signature is successfully verified, the server gains certainty that the message has not been altered during transmission and originates from a valid sender.
  4. Decision-based on the outcome of verification: Depending on the server configuration and anti-spam policies, the receiving server can take various actions, such as redirecting to the SPAM folder or rejecting the message.

DKIM authentication

Why is Sender’s Authentication a Must-Have?

Shortcomings in email sender authentication often lead to the classification of our messages by providers like Google or Yahoo as SPAM. Such a situation adversely affects the sender’s reputation and results in a decline in the reputation of the “From” domain and IP address. The consequence is a reduction in e-mail deliverability.

Major Problems That Occur When Sender Authorization is Missing.

  • Increased SPAM : Sender authorization plays a pivotal role in the way our emails are perceived by receiving servers and mailbox providers. Without it, they will most likely consider our messages suspicious or fraud, leading to their rejection or redirecting straight to the SPAM folder.
  • Bandwidth issues and delayed delivery of transactional emails: Lack of sender authentication can adversely impact throughput by increasing the risk of your emails getting blocked, delayed, or higher rejection rate. Therefore, senders should implement and configure authentication protocols regularly.
  • Vulnerability to cyberattacks: Major troubleshooting with missing a proper sender authentication is that it allows potential cyber criminals to fraud email addresses, leading to phishing attacks, identity theft, or other forms of online cybersecurity risks.
  • Lower deliverability rates: If emails are not authenticated, receiving servers may treat them as less reliable, which can result in lower delivery rates and difficulty reaching recipients’ inboxes.

To fully understand the importance of proper email sender authentication, it is certainly worth exploring the relationships between deliverability, spam prevention, sender reputation, and security. In the following section, we delve into this topic.

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Sender Authorization and Deliverability and Reputation

Deliverability and sender reputation, also known as sending reputation, are two halves of the same logical puzzle. The better the reputation influenced by sender authentication, the greater the chances of successful email delivery.

Is this email originating from an authorized domain?

This question covers one of the fundamental issues providers’ algorithms relentlessly solve. Fortunately, if we have appropriately authenticated our sending domain, we are on the way to building the sender’s reputation. What does it mean to have a good reputation? Google defines it nicely:

“High reputation has a good track record of a very low spam rate and complies with Gmail’s sender guidelines.  Mail will rarely be marked by the spam filter.“ – Google,

Sender reputation typically involves two dimensions – the reputation of the “From” domain and the reputation of the IP address, encompassing a variety of metrics.

IP Reputation and Domain “From” Reputation

A bad domain or IP address reputation indicates a significant volume of unsolicited communications has been sent from that particular infrastructure. As a result, such emails will most likely be rejected or marked as spam.

Best Practices to Improve and Protect Your Domain Reputation:

  1. Authentication: Implement proper e-mail authentication protocols to protect your domain from unauthorized sendings (email spoofing).
  2. Email database hygiene: Regularly remove non-existent email addresses from the database.
  3. Double opt-in: Use double opt-ins to verify consents and email addresses on your subscriber’s list.
  4. Avoid purchasing contacts: Never buy e-mail lists; Always use lists with consent.
  5. Sending schedule: Adhere to your sending schedule to avoid overwhelming your subscribers with too many messages; that will reduce Spam Complaints.
  6. Avoid spam-generating words: Avoid using words that trigger anti-spam filters, as these can prevent your e-mails from reaching the inbox.
  7. High-quality content: Create highly relevant, valuable content for your receivers.
  8. Monitoring results: Regularly monitor the performance of your e-mail campaign to fine-tune your sending strategy and optimize results.

Internet Service Providers (ISPs) assess a substantial number of factors associated with an IP address such as: spam rate, hard bounce rate, or the presence of Realtime Blackhole Lists RBL (Realtime Blackhole List) Based on this evaluation, providers reject potentially unwanted emails at the server level or mark them as spam. Based on this evaluation, providers reject potentially unwanted emails at the server level or mark them as spam.

Have you considered what factors can negatively affect your IP reputation?

  1. High Spam Complaint Rate: – If recipients regularly mark emails sent from a particular IP address as spam, their reputation can significantly lower. Be mindful that receiving servers consider spam complaint rates as a critical factor influencing message deliverability.
  2. High Bounce Rate: If a large number of messages from one IP address don’t reach inboxes (due to, e.g., configuration errors or issues with the subscriber list), receiving servers may see it as unwanted traffic, harming the sender’s reputation.
  3. Absence of SPF, DKIM, or DMARC Records: If a sender has not correctly configured authentication mechanisms such as SPF, DKIM, or DMARC, or they are improperly configured, this can lower the IP address’s reputation effectively.
  4. No dedicated IP: Shared versus dedicated IPs has been a dilemma for many senders. It is worth knowing that in the case of a shared IP address, the reputation is associated with the reputation of other senders using the same IP. If any of them use bad sending practices, such as distributing SPAM or unsolicited, low-quality communications, it can negatively impact the reputation of the entire sender group, including yours.
  5. Presence on RBL: When an IP address or sender domain is blacklisted, receiving servers may block or reject messages from that sender, affecting both the deliverability of email messages and the sender’s reputation.

Tools to Check Your IP & Domain Reputation – this powered by EmailLabs tool provides a straightforward way to assess emails directly from your browser, offering guidance on improvements for higher deliverability. was designed with marketing emails in mind, but it also effectively verifies transactional messages. The spam test examines the domain and IP address reputation, authentication quality, code correctness, and more. By improving the lowest-rated criteria, you increase the chances of your emails reaching your subscribers’ inboxes.


 Google Postmaster Tools enables senders to analyze the performance of their domain in the Gmail service. This tool provide domain and IP reputation insights by analyzing various met. Based on these metrics, Google assigns a reputation score to the domain and IP address used for sending emails. This score helps email senders understand how their emails are being perceived by Gmail’s spam filters and can provide insights into areas for improvement to enhance deliverability.


SNDS (Smart Network Data Services) – analyzes the collected data to assess the reputation of the sending domain and IP addresses. Reputation scoring is based on various factors such as email volume, engagement rates (open and click-through rates), complaint rates, spam trap hits, and adherence to industry best practices and email authentication standards (e.g., SPF, DKIM, DMARC).


5 Ways to Check Sending Reputation

New Gmail and Yahoo Sender Requirements

In 2024, sender authentication is even more critical due to new requirements from providers like Google and Yahoo. The aim of these changes is primarily to protect and provide a comfortable experience for the global community of email users.

“No matter who their email provider is, all users deserve the safest, most secure experience possible, … in the interconnected world of email, that takes all of us working together. Yahoo looks forward to working with Google and the rest of the email community to make these common sense, high-impact changes the new industry standard.” ” – Marcel Becker, Sr. Dir. Product at ” Marcel Becker, Sr. Dir. Product at Yahoo. “

One might feel overburdened in this web of rules even though it’s about something other than introducing new elements. ISPs aim to compel senders to adhere to well-established best practices, that have recently evolved into mandatory guidelines.

In 2024 authentication with SPF and DKIM and maintaining SPAM Complaints below the 0.3 threshold are absolute foundations for all senders. Meanwhile, those who send over 5000 messages per day must implement a DMARC at the “p=none” policy.

Overall, if we aim to keep high deliverability, we should promptly implement all required authentications. The deliverability claim for 2024 can surely be “No Auth, No Entry”.

A comprehensive article on Google and Yahoo requirements is here.

Ways to Prevent Phishing and Spoofing

Google reported that a 75% reduction in the number of unauthenticated messages received by Gmail users contributed to blocking billions of malicious messages with greater precision. – Google, October 2023. Hence, it is crucial to authenticate the email sender. 

As recipients of hundreds of emails daily, we also bear the responsibility not to click on a link that could cause financial losses in our company.  

A cybercriminal might exploit our colleague’s compromised email address to carry out a phishing attack. Therefore, in case of doubt, it is worth verifying SPF, DKIM, and DMARC authentications; moreover, each bulk sender should consider implementing BIMI.

Here, we share our Ethical Hackers’ anti-phishing practices – that might prevent you from opening Pandora’s box with your next e-mail.

Email Authentication and Global Law Enforcement

According to Statista, in 2022, the monetary damage caused by cybercrime in the United States reached a peak of 10.3 billion U.S. dollars. On the other hand, the global average data breach cost was 4.45 million U.S. dollars.

Cybercrimes impact global income, prompting law enforcement efforts to keep pace and elevate security levels worldwide. Below, we share two significant acts you should know about while managing commercial e-mail traffic.

The GDPR (General Data Protection Regulation), established in 2018 in Europe.

GDPR focuses on securing European citizens’ private data and determining how businesses handle such information. A must-have for each company that operates within Europe and processes personal data such as email addresses.

The CAN-SPAM ACT, established in 2003 in the USA,

The act was designed to penalize unsolicited commercial electronic mail transmission. It aligns seamlessly with Yahoo’s requirements. This law compels all senders to include an unsubscribe option and prevent emails from being routed through unauthorized servers. Notably, an essential rule prohibits the use of false or misleading headers in the “From,” “To,” and “Reply-To” fields.

Authenticating the domain and IP goes beyond meeting Google and Yahoo requirements; it’s also crucial for compliance with law enforcement in almost every part of the world.

Remeber, in the EmailLabs panel, you can sign a GDPR agreement that defines the terms of processing personal data and both parties’ responsibilities regarding data protection.
Go to the Administrator tab > GDPR.

Sender Authorization in EmailLabs

After introducing the elements behind email sender authentication, let’s proceed to the configuration process using the free EmailLabs configurator as an example.

In the EmailLabs panel, you can generate all the unique records, including DKIM, Tracking, Return Path, and DMARC, which you should apply to your domain/domain’s DNS records.

You must follow similar steps for every new domain “From” to which you intend to send emails. In the case of accessing DNS in your company, you may discover that the assistance of an administrator or the IT department is necessary.

Domain “From” Configurator

  1. Log in to the EmailLabs admin panel.
  2. Go to the “Administrator tab” and select the field “Sender Authentication.”.
  3. Click the “Add Domain” button.
  4. Complete the ” ‘From’ domain” field with the domain you wish to authorize.
  5. Unfold the advanced settings and fill in the “DKIM Selector” field; this selector will allow you to identify the DKIM entry in your sending domain.

Detailed instructions for configuring the “From” domain in EmailLabs.


If there is concern about adding any entries to DNS settings of your “From” domain, it is advisable to choose a subdomain and implement authentication for only a proportion of email addresses.

Subdomain Tracking Configuration

Subdomain tracking pertains to monitoring email performance metrics associated with each subdomain, including open rates, click-through rates, bounce rates, and more. This capability enhances in-depth campaign effectiveness analysis and facilitates appropriate action to improve deliverability.

Tracking subdomain

Detailed instructions for configuring the Subdomain tracking

Return-Path Subdomain Configurator

Configuration of your own Return-Path leading to a subdomain in the main domain helps facilitate the DMARC validation process. This is a simple method to improve the deliverability metrics of your messages.

Return path

Detailed instructions for configuring the Return Path in EmailLabs:

DMARC Record Configuration

  1. In the field “DMARC policies”  choose the one that suits your needs to define your e-mail placement if authentication fails.
  2. Completing the field “Percentage”  limits the volume of e-mail traffic that you wish to validate with DMARC policy to the exact percentage.
  3. In the field “ Email Address for reports”,  you simply set the e-mail address for receiving your RUA reports.



  1. After you click “Save” after a few seconds, the EmailLabs system will produce 4 entries that you should add to the DNS settings of your hosting domain.
  2. Following the implementation of the records in DNS, please allow for the propagation of changes in the domain settings, which may take up to 24 hours.
  3. Select the “Check” field in the EmailLabs panel to verify your authentication status.  
  4. The “Accepted” status indicates that the authentication process was successful, and you can send messages using email addresses set on the authorized domain.

Records verification

Detailed instructions for configuring the DMARC record in EmailLabs

Sender Authorization in EmailLabs – Full Documentation

Explore the comprehensive documentation provided by EmailLabs, where we address all questions related to the proper configuration of sender authentication and associated authentications:
Sender Authorization in EmailLabs Panel

If you have any doubts about how to fill in the fields in the EmailLabs panel correctly, please contact our Customer Support at [email protected]

Good Luck! 

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