MX records are the DNS record type that gets the most confusion in cold email infrastructure setup — because most guides conflate MX records with email sending, when MX records control email receiving. Your MX records don't affect whether your cold emails reach the primary inbox. They determine whether replies to your cold emails arrive back in your inbox. Both matter. A cold email sending domain with no MX records receives no replies — which is an obvious problem that most teams only discover after launching campaigns.
What MX Records Do and Don't Do for Cold Email
💡 TL;DR
MX records control email receiving — they tell other email servers where to deliver emails sent to your domain. For cold email, MX records are configured automatically when you set up a Google Workspace or Microsoft 365 account on a sending domain. If you're using pre-warmed inboxes from Litemail ($4.99/inbox), the inbox comes with MX records configured. MX records don't affect deliverability of outbound cold email — that's controlled by SPF, DKIM, and DMARC. What MX records do control: whether prospect replies land in your sending inbox (yes) or bounce back to the prospect (no MX records = bounced replies). Verify with MXToolbox before launching campaigns.
Here's exactly what MX records do, how to configure them for GWS and MS365 cold email sending domains, and the common errors that prevent replies from arriving.
MX Records for Google Workspace Sending Domains
When you add a custom domain to a Google Workspace account, Google Admin Console provides the MX records that need to be published in your DNS to route incoming email to that GWS inbox. These are published automatically in many setups, but if you're configuring a sending domain manually, you need to publish them explicitly.
The standard Google Workspace MX records (publish all five as MX records at the root of the sending domain):
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
All five should be published. Publishing only the priority 1 record works but creates a single point of failure — if Google's primary MX server is temporarily unavailable, incoming email (replies from prospects) will bounce rather than queue and retry on backup servers.
Verify: MXToolbox at mxtoolbox.com/MXLookup.aspx — enter the sending domain. All five Google MX records should appear. Send a test reply from an external email address to the sending inbox and confirm it arrives in the GWS inbox.
MX Records for Microsoft 365 Sending Domains
Microsoft 365 uses a single MX record format: yourdomain-com.mail.protection.outlook.com (where yourdomain-com is your sending domain with hyphens replacing dots). The priority is typically 0 for MS365 MX records.
Microsoft 365 Defender and the Microsoft 365 Admin Center both display the exact MX record value for your specific domain when you add the domain to your tenant. Use the value provided in Admin Center rather than constructing it manually — the format includes your tenant-specific identifier.
Verify: MXToolbox MX lookup for the sending domain. Should show the Microsoft protection.outlook.com record. Send a test reply from an external email to the sending inbox and confirm arrival.
MX Records vs SPF, DKIM, and DMARC — The Difference
Cold email teams frequently confuse these four record types because they're all part of email DNS configuration. The distinction:
Record Type | What It Controls | Affects Deliverability? | Affects Reply Receipt? |
|---|---|---|---|
MX | Which server receives incoming email | No | Yes — essential for replies to arrive |
SPF | Which servers are authorised to send email from your domain | Yes — authentication | No |
DKIM | Cryptographic signature proving email authenticity | Yes — authentication | No |
DMARC | Policy for unauthenticated email + reporting | Yes — authentication | No |
In short: SPF + DKIM + DMARC determine deliverability of outbound cold email. MX records determine receipt of inbound replies. All four are required for a functional cold email sending setup.
Common MX Record Errors for Cold Email Sending Domains
No MX records published: The most common error for new sending domains set up only for outbound. The domain was created, SPF/DKIM/DMARC configured, campaigns launched — but no MX records were published because the team assumed outbound doesn't need MX. Replies from prospects bounce back with "undeliverable" errors. Fix: publish the correct MX records for your inbox provider (GWS or MS365) as listed above.
MX records pointing to wrong domain: Copy-paste errors in MX record configuration that point to a different domain's mail servers. Replies get delivered to a different inbox (or no inbox) rather than the sending account. Fix: verify MX records in DNS exactly match the provider-specified values, then confirm with a test reply.
MX records present but DKIM not enabled: This doesn't affect reply receipt — but it means outbound cold email is failing DKIM authentication. Often discovered when investigating reply receipt problems (checking MXToolbox reveals correct MX records but also surfaces the DKIM failure). Fix: the DKIM and MX issues separately — both must be correct for a fully functional sending domain.
Pre-Warmed Inboxes With All Four DNS Records Configured
Litemail pre-warmed inboxes — $4.99/inbox, MX records, SPF, DKIM (2048-bit), and DMARC all configured automatically on delivery. Outbound authentication and inbound reply receipt — both handled before the inbox lands in your hands.
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All DNS records automated · No minimum order · GWS and MS365 · Delivered in 24 hours
About Litemail — Litemail provides pre-warmed Google Workspace and Microsoft 365 inboxes for cold email outreach. From $4.99/inbox with automated DNS, dedicated US and EU IPs, and full admin access. View pre-warmed inbox plans →
Related reading:
SPF/DKIM/DMARC Auto-Setup 2026 · Cold Email SPF Record Errors and Fixes 2026 · Pre-Configured Inbox With SPF/DKIM Ready · New Domain Email Deliverability Guide 2026 · Best Pre-Warmed Inbox Providers 2026 (Ranked)
Key Takeaways
MX records control email receiving — they determine where replies to your cold emails are delivered. MX records do not affect deliverability of outbound cold email. That's controlled by SPF, DKIM, and DMARC.
A sending domain with no MX records will send outbound cold email normally — but all replies from prospects will bounce back as undeliverable. Always publish MX records before launching campaigns.
Google Workspace sending domains need all five GWS MX records published (ASPMX.L.GOOGLE.COM plus four ALT records at priorities 5 and 10). MS365 sending domains need the Microsoft protection.outlook.com MX record from the Admin Center for your specific domain.
Verify MX records with MXToolbox MX lookup before campaigns launch. Then send a test reply from an external address to the sending inbox and confirm it arrives. Both checks are required — MXToolbox confirms records are published, the test reply confirms they're routing correctly.
Litemail pre-warmed inboxes configure MX records automatically as part of the GWS or MS365 account provisioning. All four DNS record types (MX, SPF, DKIM, DMARC) are handled on delivery — no manual DNS configuration required.
Frequently Asked Questions
Do I need MX records to send cold email?
No — MX records are for receiving email, not sending it. You can send cold email from a domain with no MX records. But prospect replies to your cold email will bounce back as undeliverable if there are no MX records to route incoming email to your inbox. A cold email sending domain needs both SPF/DKIM/DMARC (for outbound authentication and deliverability) and MX records (for inbound reply receipt).
What are the MX records for Google Workspace?
Five MX records: ASPMX.L.GOOGLE.COM (priority 1), ALT1.ASPMX.L.GOOGLE.COM (priority 5), ALT2.ASPMX.L.GOOGLE.COM (priority 5), ALT3.ASPMX.L.GOOGLE.COM (priority 10), ALT4.ASPMX.L.GOOGLE.COM (priority 10). All five should be published as MX records at the root of the sending domain. Litemail configures these automatically on GWS inbox delivery.
How do I check if my cold email sending domain has correct MX records?
Go to mxtoolbox.com/MXLookup.aspx and enter the sending domain. For GWS inboxes, all five Google MX records should appear. For MS365 inboxes, the Microsoft protection.outlook.com record should appear. After confirming records are published, send a test reply from an external email address to the sending inbox and confirm it arrives in the inbox — this end-to-end test confirms records are routing correctly, not just published correctly.
All Four DNS Records Configured Automatically — Including MX for Inbound Replies
Litemail pre-warmed inboxes — $4.99/inbox, MX records, SPF, DKIM (2048-bit), and DMARC all configured and verified on delivery. Outbound authentication and inbound reply receipt both handled. No manual DNS setup. No missing MX records. No bounced prospect replies. No minimum order. Delivered in 24 hours.
Get Pre-Warmed Inboxes from $4.99 →
All DNS records automated · No minimum order · GWS and MS365 available · US and EU IPs included
About Litemail — Litemail provides pre-warmed Google Workspace and Microsoft 365 inboxes for cold email outreach. From $4.99/inbox with automated DNS setup, dedicated US and EU IPs, 4 to 12 weeks of genuine warm-up history, and full admin access. View pre-warmed inbox plans →
Related reading: SPF/DKIM/DMARC Auto-Setup 2026 · Pre-Configured Inbox With SPF/DKIM Ready · Best Pre-Warmed Inbox Providers 2026 (Ranked)
