Tracking domain
Set up a CNAME so click and open tracking links in your campaigns carry your own domain instead of a shared one.
Every tracked link in a campaign points at a redirect before it reaches its destination, and open tracking loads a small image from the same place. By default those URLs sit on a shared domain. A tracking domain moves them onto a hostname of your own. When you finish this page, the links in your campaigns will show your domain to a recipient who hovers over them, and to the filters that inspect them.
Before you start
You need DNS access for the domain, and a hostname you are willing to dedicate to this. It should be a subdomain of the same domain you send from, so that everything in the message points at one recognizable name.
What a tracking domain changes#
It changes one thing: the hostname in the tracking URLs. Nothing about how tracking works, what is measured, or how reports read is different.
That one thing matters for two audiences.
Recipients. People hover over links before clicking, and mail clients show the destination in a status bar. A link that reads as a hostname on the domain the mail came from is consistent with the sender. A link on a hostname the reader has never seen, shared with every other sender using it, is the pattern people have been taught to be careful about.
Filters. Receiving systems evaluate the domains a message links to, not only the domain it came from. On a shared tracking hostname your links carry a reputation you did not create and cannot control, made up of everyone else sending through the same hostname. On your own tracking domain the link reputation is yours, and it aligns with your sending domain rather than pointing somewhere unrelated.
Be realistic about the size of the effect. A tracking domain will not rescue a list with a complaint problem, and it is worth less than authentication or list quality. It removes a specific inconsistency in your mail rather than improving your standing on its own.
Set it up#
Choose a hostname
Pick a subdomain of your sending domain and keep it dull. Something like link.example.com or click.example.com reads correctly to a person. Do not reuse a hostname that already serves a website or another service, because this record will point it elsewhere.
Add the tracking domain in the app
Enter the hostname you chose in the tracking domain setting. The screen then shows you the CNAME record it needs: the host, and the target value to point it at.
Create the CNAME at your DNS provider
Add a CNAME record with the host and target exactly as shown. Two things to watch:
- Do not invent the target. Use the value on screen. It is not something you can work out from your own domain name.
- A CNAME cannot coexist with other records at the same host. If the hostname already has an A record or a TXT record, DNS will either reject the CNAME or behave unpredictably. Choose an unused hostname instead.
If your DNS provider offers a proxy or CDN toggle on the record, leave it off. Proxying a tracking hostname interferes with the redirect.
Verify the record
Run the verification check. It looks up the hostname and confirms it resolves to the expected target. As with any DNS change, allow time for propagation before concluding a correct record is wrong. Minutes is typical, up to 48 hours is possible.
Send a test and inspect a link
Send yourself a campaign with at least one tracked link. Hover over the link, or copy it, and confirm the hostname is yours. Then click it and confirm you arrive at the right destination and the click is recorded on the campaign report.
When to do this#
A tracking domain is optional. Campaigns send and track correctly without one.
Set it up before you start sending at volume. The reason is timing rather than urgency: changing the hostname your links live on partway through a sending programme means the new hostname starts with no history at the moment your volume is highest. Doing it at the beginning, alongside authentication, means the link hostname builds its reputation at the same pace as everything else.
If you are already sending and have no tracking domain, add one during a quiet period rather than the week of a large send.
Careful
Once campaigns have gone out with tracking links on a hostname, keep that hostname resolving. Old messages stay in inboxes for years, and people click links in them. If you delete the CNAME, every tracked link in every campaign you have already sent stops working.
Troubleshooting#
Verification fails. Check the record type first. A tracking domain needs a CNAME, and a common mistake is creating an A record pointing at an address you looked up. Then check the host field format, since some DNS providers expect only the leftmost label and append the rest of the domain themselves.
Links resolve but land on an error. This is usually a proxy or CDN sitting in front of the record, or a wildcard record elsewhere in your DNS catching the hostname first. Turn the proxy off and look for a wildcard entry.
A browser warns about the connection. The hostname needs a valid certificate before links over it are safe to send. If a test link produces a certificate warning, do not send a campaign using it. Wait until the setup completes and the test link opens cleanly.
Existing links stopped working after DNS work. Somebody removed or changed the CNAME. Restore it with the target value shown in the app and the old links start working again.
Last updated September 10, 2026