CNAME lookup and custom tracking domain checker
A CNAME lookup shows which host name a name is an alias for, such as track.yourdomain.com pointing to your email tool's tracking server. Enter the host to see the full CNAME chain, check it matches the target Instantly, Smartlead or lemlist expects, and confirm HTTPS works so tracked links don't show a browser warning.
Sample result
track.acme.example points to track.acme-mail.example, as expected, and HTTPS works.
- Host
- track.acme.example
- CNAME
- track.acme-mail.example
- HTTPS
- Answered, status 200
What this means for you
Your tracking or custom domain is wired up, so tracked links should load correctly.
- Follows the CNAME chain hop by hop
- Compares the target with the one expected
- Catches doubled-domain and proxied records
- Tests HTTPS and reads CAA issuers
- CNAME
- Tracking
- HTTPS
By SimpleVerifier Team · Last updated
How do I check a custom tracking domain's CNAME?
- Enter the full host name you created, such as inst.yourdomain.com or track.yourdomain.com.
- Choose the tool it should point to (Instantly, Smartlead, lemlist) or enter another target, or just look up the CNAME.
- Press Check CNAME. The chain, the target match, HTTPS and the domain's CAA records are checked.
- Fix anything flagged at your DNS host, wait for it to propagate, then press verify in your sending tool.
Example
- You enter
- The host
track.acme.example, with the expected targettrack.acme-mail.example. - You get
- The CNAME chain is
track.acme.example→track.acme-mail.example, which resolves to203.0.113.40. The target matches what was expected and HTTPS answered with status 200. - Limits
- One host per check and 10 checks a minute per connection.
What is a CNAME record?
A CNAME (canonical name) record makes one name an alias of another: track.yourdomain.com CNAME prox.itrackly.com tells resolvers to look up the second name instead. It's defined in RFC 1034, which also sets its main rule: a name with a CNAME can't have other records, which is why you can't put one on the bare domain (yourdomain.com) alongside its MX and TXT records.
CNAMEs are public, like all DNS records, and they can chain: an alias can point to another alias. This tool follows the chain up to eight hops, flags loops, and shows the addresses at the end. For every record type on a name at once, use the DNS lookup.
How do I check a CNAME record?
Query the name for its CNAME, as this tool does from a public resolver. On a computer, nslookup -type=cname track.yourdomain.com (Windows) or dig +short CNAME track.yourdomain.com (Mac, Linux) returns the target with a trailing dot. Nothing back means the record isn't there yet, is on a different name, or is hidden by a proxy.
Two mistakes cause most failed verifications. One is typing the full host name into the DNS host field, which creates track.yourdomain.com.yourdomain.com; this tool checks for that name and says so. The other is Cloudflare's proxy: with the orange cloud on, the name returns Cloudflare addresses instead of the CNAME, and lemlist's setup guide says to set the record to DNS only.
What CNAME does a custom tracking domain need?
Whatever your sending tool's help centre or app shows; the target is theirs. When we checked on 7 October 2026, Instantly used host inst pointing to prox.itrackly.com, Smartlead used emailtracking pointing to open.sleadtrack.com, and lemlist showed its target in the app, commonly custom.lemlist.com, plus a TXT record. Our guide to custom tracking domains compares them.
The point of the record is reputation. Open pixels and tracked links otherwise use a hostname shared by every customer of the tool, so you inherit what the others send; a tracking subdomain under your own domain is used only by your mail.
Why does my tracking domain need HTTPS?
Because tracked links point at it. A link to a host with no certificate, or one that doesn't cover the name, opens with a browser warning, which is worse than no tracking. The tool usually issues the certificate once the CNAME verifies, so a fresh record can fail this check for a while.
If it keeps failing, check the domain's CAA records, which say which certificate authorities may issue for it (RFC 8659). lemlist's guide notes that CAA records can block Let's Encrypt; this tool lists the CAA issuers and warns when Let's Encrypt isn't among them.
Is this different from a DNS lookup?
| This CNAME checker | DNS lookup | |
|---|---|---|
| Follows the full CNAME chain | Yes, up to 8 hops | First hop only |
| Checks against Instantly, Smartlead, lemlist | Yes | No |
| Catches the doubled-domain mistake | Yes | No |
| HTTPS and CAA check | Yes | CAA only |
| All record types | No | Yes |
Who uses this tool, and for what?
- Cold emailers
- Confirm each sending domain's tracking CNAME before verifying it in Instantly, Smartlead or lemlist.
- Agencies
- Check tracking domains across dozens of client domains and catch the doubled-domain mistake in one lookup.
- Developers and IT
- Follow a CNAME chain, spot loops and confirm the end host answers on HTTPS.
- Marketing ops
- Verify the CNAMEs an ESP or landing-page tool asked for before launch day.
What can’t this tool tell you?
- It checks the record and HTTPS; it can't tell whether your sending tool has finished verifying the domain on its side.
- Vendor targets are from their help centres on 7 October 2026; if your app shows a different one, use that.
- A proxied record (Cloudflare's orange cloud) hides the CNAME, so the tool can only say it found an address instead.
- Answers come from a public resolver and may be cached for the record's TTL.
- It doesn't look up CNAM (caller name) for phone numbers, which is a different thing.
Common questions
- What is a CNAME lookup?
- A DNS query for a name's CNAME record, which returns the host name it's an alias of. It's how you confirm a subdomain points where a service, such as a tracking domain or website host, expects.
- How do I check CNAME records for a domain?
- Enter the exact host name (CNAMEs live on subdomains like www or track, not usually on the bare domain) in a CNAME lookup tool, or run dig +short CNAME host on Mac or Linux and nslookup -type=cname host on Windows.
- Are CNAME records public?
- Yes. Like all DNS records, anyone can look them up, which is how services verify that you've set them up.
- Can you have more than one CNAME record?
- Not on the same name: RFC 1034 allows one CNAME per name and no other records alongside it. Different subdomains can each have their own CNAME.
- How to check CNAME propagation?
- Look it up from a public resolver, as this tool does. If it shows the new target, most of the internet will too; caches holding the old answer expire after the record's TTL.
- What is the difference between an A and a CNAME record?
- An A record maps a name to an IPv4 address; a CNAME maps a name to another name, whose addresses are then used. Services that may change IPs, like tracking servers, ask for a CNAME.
Sources
You audited one domain. Cold outreach means thousands.
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