How to Check the Tracking Domain on Every Sending Domain (and Where Links Go)

Check two things on every sending domain: that its tracking hostname points at your cold email tool's target, and that a tracked link actually lands where it should. Paste all the tracking hostnames into the bulk CNAME lookup, then paste a tracked link from a test email into the bulk redirect checker.

Check all your tracking CNAMEs →

Check the tracking CNAMEs in bulk

1. Write down the tracking hostname on each sending domain, such as inst.domain1.com, inst.domain2.com.
2. Paste them into the bulk CNAME lookup: up to 100 a run, or 500 after a free Google sign-in.
3. Press Look up CNAMEs.
4. Every row should be Alias with the final target your tool gives. Flag anything Dangling, Doesn't exist, No CNAME, or pointing at the wrong target.

Then follow the tracked links

1. Send yourself a test email from each tool and copy a tracked link from it.
2. Paste the links into the bulk redirect checker and press Check redirects.
3. Each row should go from your tracking hostname to your real page and end in a 200. Look for a long chain, an extra shortener hop or a final error.

Do it by hand

Compare each tracking hostname with the target you expect, one host,target pair per line:

cat > track.txt <<'EOF'
www.github.com,github.com
www.mozilla.org,www-mozilla.fastly-edge.com
docs.github.com,github.github.io
EOF

while IFS=, read -r host want; do
  got=$(dig +short cname "$host" | sed 's/\.$//')
  if [ "$got" = "$want" ]; then echo "$host,ok"; else echo "$host,WRONG (got: ${got:-no CNAME})"; fi
done < track.txt
# www.github.com,ok
# www.mozilla.org,ok
# docs.github.com,WRONG (got: no CNAME)

We ran this on 9 November 2026 on public hostnames so the output is real; put your own tracking hostnames and your tool's target in the file. The third line shows what a missing or proxied record looks like.

Then follow a link hop by hop. Here, a public Microsoft short link:

curl -sL -m 15 -o /dev/null -D - https://aka.ms/admin | grep -iE '^(HTTP|location)'
# HTTP/1.1 301 Moved Permanently
# Location: https://admin.microsoft.com
# HTTP/2 302
# location: https://admin.cloud.microsoft/
# HTTP/2 200

Targets and common mistakes

• The target. Instantly's help article gives host inst and value prox.itrackly.com. Smartlead's help article gives open.sleadtrack.com, or app.sleadt.com if you use https links. Both pages were checked on 9 November 2026; copy what your tool's app shows, since it can change.
• Proxied records. On Cloudflare, the orange cloud makes public DNS return Cloudflare addresses, so the CNAME check fails even though the record exists. Set tracking records to DNS only unless your tool says otherwise.
• Doubled names. Typing inst.domain.com into a DNS host's name field often creates inst.domain.com.domain.com. The bulk CNAME lookup then shows Doesn't exist.
• Leftovers. A tracking CNAME left behind after you cancel a tool points at a target that may stop resolving; see find dangling CNAMEs.
• Extra hops. Shorteners inside a tracked link add a hop and another domain for filters to judge. See do URL shorteners hurt deliverability?

For one domain with an HTTPS test, use the tracking domain checker. For why to use a custom tracking domain at all, see custom tracking domains for cold email.

Next step: check the leads before the campaign

Working links don't help if the email bounces. Upload the lead list at /verify to check every mailbox without sending. The first 100 checks are free with a Google sign-in, no card.

Pro, $39 a month: Unlimited email verification.* Never metered, never cut off. See pricing.

*Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.

More: managing DNS for many cold email domains, does open tracking hurt deliverability?