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Domain Name Search4 min
How to Authenticate Subdomain Email Tracking Links
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NameSilo Staff10/1/2026
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To improve deliverability, configure a custom tracking subdomain. This replaces the generic links provided by your email platform (like Mailchimp or SendGrid) with your own branded links. To set this up, create a CNAME record in your DNS manager pointing your tracking subdomain (e.g., click.yourbrand.com) to your provider's tracking server.
What Is Click/Open Tracking?
When you send a marketing email, your platform rewrites every link before delivery. A link to yourbrand.com/offer becomes something like links.mailchimpapp.com/track/xyz123, letting the platform log the click, then redirect the visitor to the real destination. Open tracking works similarly, via an invisible tracking pixel.
By default, every customer on a shared platform uses the same generic tracking domain, so recipients' links point to a domain your brand has no connection to.
Why It Matters: A Visible Mismatch Filters Notice
This is a real, well-documented signal, just not the one commonly assumed. Many spam and anti-phishing filters run a dedicated check comparing the sender's visible brand identity against the actual domain behind each hyperlink. When an email claims to be from yourbrand.com but every link routes through a massive, shared third-party tracking domain used by thousands of unrelated senders, that mismatch is exactly the pattern phishing-detection systems flag, independent of whether SPF and DKIM are configured perfectly.
A clarification: this isn't a DMARC alignment failure. DMARC strictly evaluates whether your "From" domain aligns with the domain authenticated by SPF and/or DKIM; it never inspects hyperlinks in the body. A mismatched tracking link won't break DMARC, it gets caught by a separate heuristic many mailbox providers run alongside it, which can still hurt deliverability even when DMARC passes cleanly.
The Custom Domain Solution
Mapping your own subdomain, like click.yourbrand.com, to your provider's tracking infrastructure closes this gap. Every link now visibly belongs to your own domain, matching the brand identity recipients already trust, and removing the mismatch anti-phishing filters specifically look for.
Implementation Steps
Step 1: In your email platform's settings, locate the custom tracking domain option (sometimes called "branded links" or "click tracking domain"), and note the target hostname it provides.
Step 2: In NameSilo's DNS Manager, add a new CNAME record. Set the host to your chosen subdomain (e.g., click) and the value to the target your platform provided.
Step 3: Add the SSL validation records too, if required. A plain CNAME alone is often not enough for HTTPS. The TLS handshake happens before your request's path is read, so the server must present a valid certificate matching your exact subdomain, something a generic shared certificate can't do. Most modern platforms solve this automatically: alongside the tracking CNAME, they'll ask for one or two more records, commonly an _acme-challenge CNAME and a verification TXT record, so their system can issue and manage that certificate for you. Add every record the setup screen lists, not just the tracking CNAME.
Step 4: Return to your platform and click verify. Propagation can take minutes to 48 hours; automated certificate issuance typically follows within about 15 minutes after that.
Step 5: Send a test email and confirm the links display your branded subdomain, loading over HTTPS without a certificate warning.
Common Mistakes
Enabling Cloudflare's proxy (orange cloud) on the tracking CNAME: Click tracking depends on a direct redirect from your provider's server. Proxying that traffic intercepts and breaks the chain, causing clicks to fail. Keep this record set to DNS-only.
Adding only the tracking CNAME and skipping SSL validation records: This is the most common reason a custom domain "looks configured" but fails to verify or throws certificate errors. Add every record the setup screen lists, not just the main one.
What This Means for You
Configure your branded tracking subdomain directly through NameSilo's DNS Manager, closing the visible link-mismatch gap that sits alongside, but separate from, your SPF and DKIM setup. If you're sending through NameSilo Email rather than a third-party platform, the same DNS Manager handles that authentication too.
Frequently Asked Questions
Why are my marketing emails going to spam?
Often authentication, content, or link-mismatch signals working against sender reputation.
What is a custom tracking domain?
A branded subdomain replacing your email platform's generic, shared tracking links.
How do email click trackers work? Links are rewritten to route through the platform's server before redirecting visitors.
Why does Mailchimp rewrite my links?
To measure click activity, using its own tracking domain by default.
How do I add a tracking CNAME record?
In DNS Manager, add a CNAME with your subdomain host and the provider's target value.
Can a custom tracking link improve deliverability?
Yes, by removing a shared-domain mismatch some spam filters flag independently of DMARC.
What is email link alignment?
Matching visible links to your actual brand domain rather than a shared third party.
How do I edit CNAME records at NameSilo?
DNS Manager, add or edit the CNAME record with your desired host and value.
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NameSilo StaffThe NameSilo staff of writers worked together on this post. It was a combination of efforts from our passionate writers that produce content to educate and provide insights for all our readers.
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