Cold Email Setup · 5 min read

lemlist Setup: Custom Tracking Domain, SPF, DKIM, DMARC

lemlist sends through the mailboxes you connect, so SPF, DKIM and DMARC are set up with your mailbox provider. lemlist adds a custom tracking domain, which takes a CNAME and a TXT record on each domain you use for tracking.

Published October 26, 2026

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What lemlist handles, and what you must set up

lemlist does not send mail from its own servers for your domain. It logs in to the mailboxes you connect and sends through them. So the provider of those mailboxes is the one that must be in your SPF record and must sign with DKIM. lemlist's only DNS record is the custom tracking domain, which puts open and click tracking links on your own domain instead of a host shared by many senders.

Step 1: SPF, DKIM and DMARC on every sending domain

Do this on each secondary domain you send from, not only the main one.

RecordGoogle WorkspaceMicrosoft 365
MXsmtp.google.com (priority 1)The host shown in the Microsoft 365 admin center (often *.mail.protection.outlook.com)
SPF (TXT at @)v=spf1 include:_spf.google.com ~allv=spf1 include:spf.protection.outlook.com ~all
DKIMTXT at google._domainkey, generated in Admin console → Gmail → Authenticate emailCNAMEs at selector1._domainkey and selector2._domainkey, then turn DKIM on in Microsoft Defender
DMARC (TXT at _dmarc)v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com

Keep one SPF record per domain. If the domain also sends through another service, add its include to the same record and stay under 10 DNS lookups.

Step 2: The lemlist custom tracking domain

Type:   CNAME
Host:   trail            (becomes trail.yourdomain.com)
Value:  custom.lemlist.com

lemlist also needs a TXT record at @ with a value it generates for each tracking domain. It appears when you try to apply the CNAME in lemlist; add it exactly as shown.

Then in lemlist: Settings → Sending settings → Email → Sending email addresses → Settings next to the address. Add the tracking domain, then click Check setup.

Source: lemlist help center. Check it if the value changes; tracking providers sometimes move hosts.

Do you need open tracking at all?

Open tracking adds an image to every email, and Apple Mail Privacy Protection loads those images automatically, so open rates are no longer reliable. Many cold email teams turn open tracking off and measure replies. If you track clicks or opens, use a custom tracking domain so your links do not share a reputation with every other lemlist customer.

lemlist-specific notes

  • lemlist suggests host names such as trail, route or lemtrail. Any is fine; it must point to custom.lemlist.com.
  • Some DNS providers reject the trailing dot in custom.lemlist.com. — if validation fails, try the value without it.
  • A tracking domain set at team level applies to everyone; one set on a single address overrides it for that user.
  • Click tracking must also be turned on in the campaign's Tracking settings, or links are not tracked even with a working domain.
  • On Cloudflare, set the CNAME to "DNS only" (grey cloud). lemlist says DNS changes can take up to 72 hours.

Step 3: Check every domain, and keep checking

Run the cold email domain health check on up to 5 sending domains at once. Most problems appear later, not on day one: a DNS move drops the DKIM record, someone adds a second SPF record, or a domain lands on a blocklist. Domain monitoring checks every domain daily and sends one alert with the fix.

Know the day your email setup breaks

Most delivery problems start when a DNS record changes, a key is removed or a domain lands on a blocklist. EmailHealth checks your sending domains every day and sends one alert, by email, Slack or webhook, with the exact fix.

1 domain free. Sending from many domains (cold email, agencies, MSPs)? Early access covers 10.

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Check up to 5 sending domains