Domain Overview
DNS: ✓ 2mo ago
Checker: ✓ 2mo ago
substack.com
Yes
✓ Yes
Mailgun
No
No
⚠ Yes
No
No
Checked via [email protected]
· 2026-03-30 03:05:41 UTC · ↺ Refresh
MX Hostnames
- mxa.mailgun.org
- mxb.mailgun.org
MX Priorities
- mxa.mailgun.org: 10
- mxb.mailgun.org: 10
A / AAAA Records
- 104.18.37.200 (no PTR)
- 172.64.150.56 (no PTR)
- 2606:4700:4400::ac40:9638 (no PTR)
- 2606:4700:440b::6812:25c8 (no PTR)
Mail Server IPs
- 34.160.63.108 ↩ 108.63.160.34.bc.googleusercontent.com
- 34.160.157.95 ↩ 95.157.160.34.bc.googleusercontent.com
SOA Record
Raw SOA
ali.ns.cloudflare.com dns.cloudflare.com 2399990522 10000 2400 604800 1800
Primary NS (mname)
ali.ns.cloudflare.com
Admin Email (rname)
dns@cloudflare.com
Serial
2399990522
Refresh
10000s
Retry
2400s
Expire
604800s
Minimum TTL
1800s
Nameservers (NS)
lee.ns.cloudflare.com
ali.ns.cloudflare.com
SPF Record
✓ Soft Fail (~all)
v=spf1 include:_spf.google.com include:mailgun.org include:mail.zendesk.com ~all
📊 DNS lookups: 3/10
~ Soft fail (~all) — moderate enforcement
DMARC Record
✓ Reject
v=DMARC1; p=reject; pct=100; rua=mailto:[email protected]; sp=reject; aspf=r;
✓ Reject — strongest protection
📋 SPF alignment: Relaxed
· DKIM alignment: Relaxed
📧 Reports → mailto:[email protected]
↳ Subdomain policy: reject
DKIM Selectors
✓ 1 found
google._domainkey
✓ Public key: 197 chars (valid)
✓ DKIM properly configured for selector: google
Checked: google, selector1/2, default, mail, dkim, k1, s1/2, zoho, sendgrid, mxvault, amazonses
All TXT Records
9 records- tiktok-developers-site-verification=A9XRSo8lWy5CPFJ0bqI04KCpUZGAAq7p
- SPFv=spf1 include:_spf.google.com include:mailgun.org include:mail.zendesk.com ~all
- facebook-domain-verification=8vbxp2ntmkudc6is3h5r840c9fwo7f
- google-site-verification=4V_X38Yf0J4VJcWFwtG38bOS1nkOWeIWJhticlMgNQE
- google-site-verification=DAkdykID6WqQM6tT7IfSu9_uB7-qIdB039MA_C3T3eA
- google-site-verification=FfNIQIxsRHpj3Y7E_d3N6GFqGgWDZ-sfYojqCilwtqE
- google-site-verification=SXEl7_p4SBszcanSWwVc_3-RFky80c0-94janbeeWI4
- google-site-verification=vQEKLOUDfKNOQAv9W3EUMiRD6e5ibAEPhc2yCzP7big
- tiktok-developers-site-verification=7PgqCAJ52ILLOqf2KELd8uaRfJpuzaLQ
Full email verification for substack.com
Run SMTP check, SPF/DKIM/DMARC and catch-all detection.
SPF / DKIM / DMARC Get 1,000 Free Credits