What Smartlead handles, and what you must set up
Smartlead 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. Smartlead'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.
| Record | Google Workspace | Microsoft 365 |
|---|---|---|
| MX | smtp.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 ~all | v=spf1 include:spf.protection.outlook.com ~all |
| DKIM | TXT at google._domainkey, generated in Admin console → Gmail → Authenticate email | CNAMEs 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 Smartlead custom tracking domain
Type: CNAME
Host: emailtracking (becomes emailtracking.yourdomain.com)
Value: open.sleadtrack.comThen in Smartlead: In the email account's settings, fill in the custom tracking domain field with emailtracking.yourdomain.com and click Verify CNAME.
Source: Smartlead 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 Smartlead customer.
Smartlead-specific notes
- Smartlead allows 30 minutes to 24 hours for the CNAME to propagate before Verify CNAME succeeds.
- Smartlead lets you use one aged, well-reputed domain as a shared tracking domain for several sending domains, instead of one per domain.
- The verification link opens an nslookup page: the canonical name must show open.sleadtrack.com.
- On Cloudflare, a proxied (orange cloud) CNAME usually breaks tracking hosts; set it to "DNS only".
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.