Email Domain Authentication in eSputnik

This article explains how to authenticate your email sending domain in eSputnik using SPF and DKIM DNS records. Domain authentication helps mailbox providers verify that eSputnik is allowed to send emails on behalf of your domain and reduces the risk of sender forgery.

You will learn how to choose one of the available configuration methods — Full, Full +, or Subdomain — add the required DNS records, configure forwarding when needed, and verify the domain status in eSputnik.

How Email Domain Authentication Works

Reteno uses two main mechanisms to authenticate your sending domain:

• DKIM (DomainKeys Identified Mail) allows eSputnik to sign emails with a private key. Recipient mail servers verify the signature using a public key stored in your domain's DNS records.
• SPF (Sender Policy Framework) checks whether an email was sent from a server authorized in the domain's DNS records.

Together, these mechanisms increase mailbox providers' trust in your messages and reduce the likelihood that legitimate emails are identified as spam.

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Note

• Read the email authentication FAQ to find answers to frequently asked questions about digital signatures.
• To ensure successful email delivery to Apple’s private email relay, you must register your domains with Apple. Learn how to deliver emails to Apple private relay addresses.

Before You Start

Make sure you have:

• Access to the DNS settings of the domain or subdomain you want to authenticate.
• A domain or subdomain that will be used in the sender address.
• Access to mailbox or forwarding settings if you use the Full method and need to configure forwarding for bounce+* addresses.
• Enough time for DNS changes to propagate. Some DNS servers may need up to 48 hours to apply changes.

Set Up a Configuration Method

eSputnik supports three domain configuration methods.

We recommend using Full + when possible. If this method is not available because of DNS, mailbox, or infrastructure restrictions, use Subdomain.

Method 1: Full

1. Go to Settings → Domain verification and click New domain.

2. Click Complex server configuration.

The Full configuration method is selected by default.

3. Click Next.

4. Specify your domain and click Start verification.

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Note

Use your domain name instead of yourdomain.com.

eSputnik checks your domain's DNS records and suggests creating new records or modifying existing ones.

5. Copy and paste each value from the Name and Data fields into the corresponding record types for your domain.

6. Set up automatic forwarding for all emails sent to the bounce+* address in your domain to [email protected].

The asterisk in bounce+* means that any number of valid characters can appear after bounce+.

The easiest way to set up this forwarding is when your domain mail is hosted on Google servers. Google discards the suffix after the plus sign in the address. In this case, create a bounce mailbox and forward all incoming emails to [email protected].

If your mail service does not support plus addressing, set up a mailbox that receives messages sent to non-existent mailboxes on your domain. In this mailbox, create a filter:

• If the email is sent to an address starting with bounce+, forward it to [email protected].
• Otherwise, delete it.

The forwarding mechanism is checked during domain verification.

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Note

We also recommend forwarding copies of emails sent to the abuse address in your domain to [email protected]. This helps us respond to complaints promptly.

7. Return to your eSputnik account and click Verify domain.

If the setup is correct, the domain status changes to Domain verified.

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Note

Some DNS servers need up to 48 hours to apply all changes.

Example of email headers in Gmail after domain verification:

The email is signed using the DKIM of both the eSputnik domain and your domain.

Method 2: Full +

1. Go to Settings → Domain verification and click New domain.

2. Specify the domain name and an unused name for the technical domain. For example, email, promo, support, or another name. For clarity, the example below uses sub.

3. Click Start verification.

eSputnik checks your domain's DNS records and suggests creating new records or modifying existing ones.

4. Copy and paste each value from the Name and Data fields into the corresponding record types for your domain.

5. Return to your eSputnik account and click Verify domain.

If the setup is correct, the domain status changes to Domain verified.

Example of email headers in Gmail after domain verification:

The email is signed using the DKIM of both the eSputnik domain and your domain.

Method 3: Subdomain

Use this method when you want to authenticate a dedicated subdomain and handle spam complaints and errors automatically.

This option is also suitable when you want to separate the reputation of your marketing campaigns from transactional and other communications.

1. Go to Settings → Domain verification and click New domain.

2. Click Complex server configuration.

3. Select Subdomain and click Next.

4. Specify a subdomain and click Start configuration.

eSputnik checks your domain's DNS records and suggests creating new records or modifying existing ones.

5. Copy and paste each value from the Name and Data fields into the corresponding record types for your domain.

6. Return to your eSputnik account and click Verify domain.

If the setup is correct, the domain status changes to Domain verified.

Example of email headers in Gmail after domain verification:

The email is signed using the DKIM of the eSputnik domain and your subdomain.

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Note

• In this option, all mail for the selected subdomain will arrive at our mail servers and be forwarded to your address, which must be specified in the reply field.
• The address indicated in the reply field must be valid. You must regularly review it and respond to emails arriving at it.
• Recipients can reply to emails and request to unsubscribe from your campaigns. You must unsubscribe such recipients immediately.

See how to set up email domain authentication on Cloudflare.

Verify Domain Settings

After you add or update the required DNS records, return to Settings → Domain verification in eSputnik and click Verify domain.

If the setup is correct, the domain status changes to Domain verified.

If eSputnik detects issues with the DNS records, a warning appears next to the verification status. Click the warning to view the recommended changes, update the records in your DNS provider, and then click Refresh in eSputnik.

DNS changes may take up to 48 hours to propagate. If the records were added recently and verification fails, wait until propagation is complete and try again.

Any service that allows DNS queries, such as DNS Record Query, can check the availability of your published DNS records to mail servers.

We recommend using SPF Policy Tester to check that your SPF record is generated correctly and meets the standard's limitations.

Additional DNS Settings

If necessary, you can grant us access to Postmaster Tools analytics. To do this, we will provide a TXT or CNAME record that needs to be added to the DNS. Learn more about Google Postmaster Tools DNS verification.

Troubleshooting

Domain Verification Fails

Check that each DNS record was added with the exact Name and Data values shown in eSputnik. Also make sure the record type is correct.

If you added the records recently, wait until DNS propagation is complete. Some DNS servers may need up to 48 hours to apply changes.

SPF Record Is Invalid

Use an SPF validation tool to check whether the SPF record is generated correctly and does not exceed standard SPF limitations.

Forwarding for bounce+* Does Not Work

For the Full method, make sure all emails sent to bounce+* addresses in your domain are forwarded to [email protected].

• If your mail provider supports plus addressing, create a bounce mailbox and forward all incoming emails from this mailbox to [email protected].
• If your mail provider does not support plus addressing, create a mailbox that receives messages sent to non-existent addresses in your domain. In this mailbox, set up a filter: if an email is sent to an address that starts with bounce+, forward it to [email protected]; otherwise, delete it.

The forwarding mechanism is checked during domain verification.

Subdomain Replies Are Not Handled Correctly

For the Subdomain method, make sure the reply address is valid and regularly monitored. Recipients can reply to your campaigns or request to unsubscribe, and such requests must be processed promptly.

eSputnik Reports Issues After the Domain Was Verified

eSputnik regularly checks domain settings. If the settings become invalid, eSputnik notifies you by email, and key signing for your domain may be suspended until the issue is fixed.

How eSputnik Monitors Domain Settings

eSputnik regularly checks whether your DNS settings remain valid.

If the settings become invalid, we will notify you by email. Until the issue is resolved, key signing for your domain will be suspended.

Read automatic service emails carefully. If you receive a message about a domain settings issue, contact our support team for help.

Deleting a Domain

Click the trash can icon in the right column to delete a domain and confirm the action.