Check MX records, mail server priority, and email routing for any domain. Instant results with provider identification.
MX (Mail Exchange) records are DNS records that tell the internet which mail servers accept email for your domain. Every time someone sends an email to an address at your domain, the sending server performs a DNS lookup to find your MX records and determine where to deliver the message.
Think of MX records as a mailing address for your domain's email. When someone sends an email to you@yourdomain.com, their mail server doesn't just magically know where to deliver it. It needs directions. MX records are those directions — they point the sending server to the exact mail servers that handle your incoming email.
Each MX record contains two critical pieces of information: a mail server hostname (like aspmx.l.google.com) and a priority value (like 10). The priority value determines the order in which mail servers are tried — lower numbers mean higher priority.
Without MX records, email sent to your domain has nowhere to go. The sending server looks up your domain, finds no mail servers listed, and the message bounces back to the sender. This is why MX records are the first thing to check when email delivery fails.
MX records are stored in your domain's DNS settings alongside other record types like A records, CNAME records, and TXT records. You manage them wherever you manage your domain's DNS — your domain registrar (GoDaddy, Namecheap, Cloudflare, Porkbun, etc.) or a dedicated DNS provider.
Unlike SPF records (which are limited to one per domain), you can and should have multiple MX records pointing to different mail servers. This provides redundancy — if your primary mail server goes down, email is automatically routed to the backup servers. Use our MX lookup tool above to see exactly what your domain's MX records look like right now.
MX record resolution happens behind the scenes every time someone sends an email to your domain. Here's the step-by-step process:
A person or automated system sends a message to an address at your domain (e.g., hello@yourdomain.com). The sending mail server needs to figure out where to deliver it.
The sending server performs a DNS lookup asking: "What are the MX records for yourdomain.com?" This is the exact same lookup our MX lookup tool performs above.
The DNS response includes all of your MX records with their priority values and hostnames. A domain with Google Workspace might return five MX records with priorities 1, 5, 5, 10, and 10.
The sending server tries the MX record with the lowest priority number first (lowest number = highest priority). It resolves the hostname to an IP address and opens an SMTP connection.
If the primary server is unreachable or returns an error, the sending server moves to the next-lowest priority MX record. This failover mechanism is why having multiple MX records matters.
If a server accepts the message, delivery is complete. If all MX servers fail, the sending server queues the message and retries periodically for up to 5 days before generating a permanent bounce.
The priority (or preference) value in an MX record controls the delivery order. Lower numbers indicate higher priority. A record with priority 1 is tried before a record with priority 10. If two records share the same priority, the sending server picks one at random — a simple form of load balancing.
1-5
Highest Priority
10
Standard Primary
20
Secondary/Backup
30+
Tertiary/Overflow
After running a domain through our MX record lookup, here's how to interpret each field in the results.
The fully qualified domain name (FQDN) of the mail server that accepts email for the domain. Examples include aspmx.l.google.com for Google Workspace or yourdomain-com.mail.protection.outlook.com for Microsoft 365. This hostname must resolve to a valid A record (an IP address) for mail delivery to work.
A numeric value that determines the order in which mail servers are tried. The server with the lowest priority number is tried first. If it's unreachable, the next-lowest priority server is tried. Common values are 1, 5, 10, 20, and 30.
The number of seconds that DNS resolvers should cache this MX record before re-querying. A TTL of 3600 means DNS resolvers will cache the record for one hour. Lower TTLs (like 300) mean changes propagate faster but increase DNS query volume.
The resolved IP address of the mail server hostname. This is the actual network address where the sending server will attempt to deliver the email via SMTP. If the hostname doesn't resolve to an IP, mail delivery will fail.
These are the issues we see most often when running MX lookups. If your results look wrong, one of these problems is likely the cause.
Your domain has no MX records at all. Email sent to your domain will bounce immediately because the sending server has no way to know where to deliver it.
Fix: Add the MX records provided by your email provider. If you use Google Workspace, you need five MX records. If you use Microsoft 365, you need one.
Your MX records exist but the priority numbers are wrong, directing email to the wrong server first. For example, your backup server has priority 1 while your primary has priority 20.
Fix: Adjust priority values so your primary mail server has the lowest number (highest priority). Follow your email provider's recommended priority values exactly.
You switched email providers but forgot to remove the old MX records. Now email delivery is split — some messages go to your new provider, some go to the old one (where your mailbox no longer exists).
Fix: Delete all MX records from your previous email provider before or immediately after adding your new provider's records. Run an MX lookup to verify only your current provider appears.
You have MX records pointing to two different email providers (e.g., both Google and Microsoft). This splits incoming email unpredictably between the two services.
Fix: Choose one email provider for your domain and remove all MX records for the other. If you need both services, use subdomains (e.g., marketing.yourdomain.com for one provider).
Your MX record's hostname resolves to a CNAME record instead of an A record. This violates RFC 2181 and RFC 5321 and can cause unpredictable delivery failures with strict mail servers.
Fix: Ensure every MX hostname resolves directly to an A record (an IP address), not a CNAME. Contact your email provider if you're unsure which hostname to use.
Every email provider requires specific MX records. Here's what the correct MX records look like for the most common providers. If your MX lookup results don't match what's listed below for your provider, you have a configuration problem.
Google Workspace uses five MX records with staggered priorities for redundancy. The primary record at priority 1 handles most traffic, with four alternates as failovers.
Priority 1 — aspmx.l.google.com
Priority 5 — alt1.aspmx.l.google.com
Priority 5 — alt2.aspmx.l.google.com
Priority 10 — alt3.aspmx.l.google.com
Priority 10 — alt4.aspmx.l.google.com
Microsoft 365 uses a single MX record that's unique to each tenant. The hostname includes your domain name with hyphens replacing dots.
Priority 0 — yourdomain-com.mail.protection.outlook.com
Zoho provides three MX records for redundancy. The specific hostnames vary by region (US, EU, India).
Priority 10 — mx.zoho.com
Priority 20 — mx2.zoho.com
Priority 50 — mx3.zoho.com
If you run your own mail server or use a less common provider, your MX records will point to custom hostnames. The key requirement is that each hostname must resolve to a valid A record and the server must be running an SMTP service.
Priority 10 — mail.yourdomain.com
Priority 20 — mail2.yourdomain.com
Setting up MX records is straightforward once you know what values to enter. Here's a step-by-step guide that works with any domain registrar or DNS provider.
Sign into your email provider's admin console (Google Admin, Microsoft 365 Admin, Zoho, etc.) and find their DNS setup instructions. They'll give you the exact hostnames and priority values to use.
Go to wherever you manage your domain's DNS settings -- your domain registrar (Namecheap, GoDaddy, Porkbun) or a DNS provider like Cloudflare. Navigate to the DNS management section for your domain.
If you're switching email providers, delete all existing MX records first. Having MX records for two providers simultaneously will split your email delivery unpredictably.
Create a new MX record for each entry your provider specifies. Set the Type to MX, the Host/Name to @ (or leave blank for the root domain), the Value to the mail server hostname, and enter the priority number.
A TTL of 3600 seconds (1 hour) is standard. If you're in the middle of a migration, temporarily lower it to 300 seconds (5 minutes) so changes take effect faster. Raise it back to 3600 after everything is working.
Wait 5-15 minutes, then use our MX lookup tool above to confirm your new records appear correctly. Send a test email to verify delivery works end to end.
If you're migrating between email providers, do not delete your old MX records until your new provider is fully configured and tested. During the transition, emails might be delivered to either provider depending on DNS caching. Lower your TTL to 300 seconds a few days before the migration to minimize this window.
An MX (Mail Exchange) record is a type of DNS record that specifies which mail servers are responsible for receiving email on behalf of a domain. Each MX record contains a server hostname and a priority value. When someone sends an email to your domain, the sending server looks up your MX records to find where to deliver the message.
The easiest way is to use our free MX lookup tool at the top of this page. Enter your domain name and you'll see all MX records including mail server hostnames, priority values, TTL, and resolved IP addresses. You can also check from the command line using "nslookup -type=mx yourdomain.com" on Windows or "dig mx yourdomain.com" on Mac/Linux.
MX record priority (also called preference) is a number that determines the order in which mail servers are contacted for delivery. Lower numbers indicate higher priority. If your primary server has priority 10 and your backup has priority 20, sending servers will always try the primary first and only fall back to the backup if the primary is unreachable.
Yes. Most domains have two or more MX records for redundancy. If the highest-priority mail server is unavailable, the sending server automatically tries the next one in the list. Google Workspace, for example, provides five MX records with different priorities to ensure mail delivery even if some servers experience issues.
If MX records are missing, email sent to your domain will bounce -- the sending server has no way to know where to deliver the message. If MX records point to the wrong server (like an old provider you no longer use), email may be delivered to a server where your mailbox doesn't exist, resulting in bounces or lost mail.
MX record changes typically propagate within minutes to 48 hours, depending on the TTL value of the existing record. If your old MX record had a TTL of 3600 (1 hour), most DNS resolvers will pick up the change within an hour. To speed things up, lower your TTL to 300 seconds before making changes.
An MX record tells sending servers which mail server handles email for a domain. An A record maps a hostname to an IP address. They serve different purposes but work together: the MX record provides the mail server's hostname, and then an A record resolves that hostname to an IP address so the sending server knows where to connect.
Yes. Google Workspace requires you to add five MX records to your domain's DNS settings. The primary record points to aspmx.l.google.com with priority 1, followed by four alternate servers at priorities 5, 5, 10, and 10. Without these records, email can't route to your Google Workspace mailboxes.
Your MX records are just one piece of your email configuration. Make sure everything else is dialed in too:
ScaledMail configures MX records, SPF, DKIM, and DMARC correctly for every inbox from day one. No DNS headaches, no misconfigured mail routing.
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