Email Domain Checker — Verify Email Domain Configuration
Instantly analyze any email domain's DNS records, mail server configuration, and authentication setup. Identify deliverability issues, verify MX records, check SPF/DKIM/DMARC compliance, and ensure your domain is properly configured for reliable email delivery.
What Does Our Domain Checker Verify?
Our email domain checker performs a comprehensive analysis of your domain's mail infrastructure, examining every layer from basic DNS resolution to advanced authentication protocols. Here is what we check and why each element matters for email deliverability.
DNS Record Validation
We verify that your domain has valid DNS records and is properly resolving. This includes checking A records, AAAA records (IPv6), NS records, and overall DNS health. A domain without proper DNS configuration cannot send or receive email reliably. We also check for DNS propagation issues that can cause intermittent delivery failures and verify that your nameservers are responding correctly.
MX Record Analysis
Mail Exchange records tell other servers where to deliver email for your domain. We verify MX records exist, check their priority ordering, confirm the target mail servers are reachable, and test response times. Missing or misconfigured MX records are the most common cause of complete email delivery failure. We also identify backup MX servers and verify failover configuration.
SPF Record Check
Sender Policy Framework records specify which servers can send email for your domain. We parse your SPF record, validate the syntax, count DNS lookups (limit of 10), check for common errors like multiple SPF records, and verify that all your sending services are included. A missing or broken SPF record causes authentication failures. Learn more with our dedicated SPF, DKIM, DMARC checker.
DKIM Configuration
DomainKeys Identified Mail provides cryptographic email authentication. We check for DKIM records at common selectors, verify public key validity, confirm key length meets current security standards (2048-bit recommended), and detect expired or revoked keys. DKIM ensures emails are not tampered with in transit and provides strong sender authentication.
DMARC Policy Review
DMARC ties SPF and DKIM together and tells receivers how to handle authentication failures. We check for a DMARC record at _dmarc.yourdomain.com, validate the policy setting (none, quarantine, reject), verify reporting addresses, and assess alignment requirements. DMARC is essential for preventing domain spoofing and phishing attacks.
Blacklist Monitoring
We check your domain and associated IP addresses against major email blacklists including Spamhaus, Barracuda, SORBS, and others. Being listed on a blacklist can cause widespread delivery failures. Early detection through our checker allows you to take corrective action before your campaigns are affected. Check your full email deliverability for a complete reputation analysis.
Why Check Email Domain Configuration?
Regular domain configuration checks are essential for maintaining healthy email deliverability. DNS records can break silently, authentication can expire, and configuration drift happens over time. Here are four critical reasons to check your domain regularly.
Prevent Delivery Failures Before They Happen
DNS misconfigurations, expired DKIM keys, and broken SPF records can silently sabotage your email delivery. By the time you notice bounces or declining open rates, the damage to your sender reputation may already be significant. Regular domain checks catch these issues early, before they impact your campaigns. A quick check before every major campaign launch can save thousands of failed deliveries.
Verify Changes After DNS Updates
Every time you switch email providers, add a new sending service, or make DNS changes, your email authentication can break. Adding a new ESP without updating your SPF record causes authentication failures for emails sent through that service. Our domain checker confirms that all your DNS records are correctly configured after any infrastructure change, ensuring continuity of service.
Meet Google and Yahoo Sender Requirements
Since February 2024, Google and Yahoo require bulk senders (5,000+ emails per day) to have valid SPF, DKIM, and DMARC records. Non-compliant senders face throttling, spam folder placement, or outright rejection. Our domain checker verifies compliance with these requirements so you can fix issues before they impact delivery. The email verification service ensures your entire sending infrastructure is compliant.
Protect Against Domain Spoofing
Without proper authentication, attackers can send emails that appear to come from your domain. This damages your brand reputation and exposes your customers to phishing attacks. Our domain checker evaluates your authentication posture and recommends improvements. A domain with p=reject DMARC policy, valid SPF, and active DKIM provides the strongest protection against email impersonation.
Understanding Domain Check Results
Our domain checker provides detailed results for each aspect of your email configuration. Here is what each result means and how to interpret the findings for your domain.
Pass (Green)
The check passed successfully. Your configuration for this element is correct and following best practices. For example, a green SPF result means your SPF record is syntactically valid, within the 10-lookup limit, and includes all necessary sending sources. No action required — your setup is optimal for this check.
Warning (Yellow)
The check passed but with concerns. Your configuration works but could be improved. Common warnings include SPF records using soft fail (~all) instead of hard fail (-all), DMARC policy set to none (monitoring only), or DKIM keys using 1024-bit encryption instead of the recommended 2048-bit. Address these warnings to strengthen your email security.
Fail (Red)
The check failed. This indicates a critical configuration issue that is likely impacting your email delivery. Failed checks include missing MX records, no SPF record found, DKIM key not published, or invalid DMARC syntax. These issues should be fixed immediately as they directly cause authentication failures and reduced deliverability.
Not Found (Gray)
The record does not exist. While some records are optional, missing authentication records leave your domain vulnerable and reduce trust with receiving mail servers. A missing DMARC record, for example, means receiving servers have no policy to follow when SPF or DKIM fails. We recommend configuring all authentication records for maximum deliverability and security.
Common Domain Configuration Issues
These are the most common configuration issues we find when checking email domains. Most can be resolved with simple DNS record changes.
Missing MX Records
Without MX records, email servers do not know where to deliver messages for your domain. This causes complete delivery failure. Solution: Add MX records pointing to your email provider's mail servers. For Google Workspace, add records like ASPMX.L.GOOGLE.COM with appropriate priority values. Allow up to 48 hours for DNS propagation.
SPF Too Many Lookups
The SPF specification limits DNS lookups to 10. Each include:, a:, mx:, and redirect= mechanism counts as one lookup. Exceeding this limit causes SPF to return PermError, which many receivers treat as a fail. Solution: Replace include: statements with direct IP ranges where possible, or use an SPF flattening service.
Duplicate SPF Records
Having two or more TXT records that start with v=spf1 causes SPF to fail with PermError. This commonly happens when adding a new email service without merging into the existing SPF record. Solution: Combine all authorized senders into a single SPF record. Use include: for each service in one record.
Expired DKIM Keys
DKIM keys can expire or become invalid if the private key is rotated without updating the DNS record. This causes DKIM verification to fail for all outgoing messages. Solution: Generate a new DKIM key pair through your email provider, update the DNS TXT record with the new public key, and verify with our SPF/DKIM/DMARC checker.
No DMARC Record
Without DMARC, receiving servers have no instructions for handling emails that fail SPF and DKIM. Your domain is also more vulnerable to spoofing. Solution: Add a DMARC TXT record at _dmarc.yourdomain.com. Start with v=DMARC1; p=none; rua=mailto:reports@yourdomain.com to begin monitoring.
Misconfigured Mail Server
Mail servers that do not respond properly to SMTP connections, have SSL certificate issues, or return incorrect responses can cause delivery problems. This includes incorrect HELO/EHLO identification, missing reverse DNS (PTR) records, and self-signed certificates. Solution: Ensure your mail server has valid SSL certificates, correct PTR records, and responds properly to SMTP commands.
Domain Checker for Bulk Verification
Need to check domains for an entire email list? Our bulk verification tools automatically validate the domain for every email address in your list, flagging addresses on domains with configuration issues.
Bulk List Domain Analysis
When you upload a list to our bulk email verifier, we perform domain-level checks on every unique domain in your list. This includes MX record validation, SPF verification, and catch-all detection. The results show you which domains are healthy and which have configuration issues that might affect deliverability. This domain-first approach allows us to process large lists efficiently without redundant checks.
API Integration for Automated Checking
Our email verification API includes domain-level checks in every verification request. When you verify an email address through the API, the response includes the domain health status, MX record details, and authentication configuration. Use this data to make intelligent decisions about email acceptance in your application, automatically rejecting addresses from misconfigured or suspicious domains.
Combine domain checking with our full email verification service for comprehensive list hygiene. Verify addresses, validate domains, and protect your sender reputation all in one workflow.
Email Domain Checker FAQ
Our domain checker verifies MX records (mail server configuration), SPF records, DKIM records, DMARC policy, domain age and registration status, SSL/TLS configuration on the mail server, and overall mail server health and responsiveness.
Yes, our tool checks if the domain has valid MX records pointing to active mail servers. We also test the SMTP connection to verify the mail server is accepting connections and responding correctly to ensure the domain can actually receive email.
Newly registered domains (less than 30 days old) are often associated with spam, fraud, and disposable email services. Our checker flags new domains as higher risk. Established domains with proper email configuration are considered lower risk.
Yes, our bulk domain checker accepts a list of domains and checks all of them simultaneously. This is useful for verifying the domains in your email list or auditing the email configuration of your organization multiple domains.
We assign a domain health score from 0-100 based on DNS configuration completeness, authentication setup (SPF, DKIM, DMARC), mail server responsiveness, domain age, and historical reputation data. Scores above 80 indicate a healthy, well-configured domain.