Domain Overview
DNS: ✓ 2mo ago
Checker: ✓ 2mo ago
castle.io
Yes
✓ Yes
Google
No
No
⚠ Yes
No
No
Did you mean: [email protected]
Checked via [email protected]
· 2026-03-25 03:45:27 UTC · ↺ Refresh
MX Hostnames
- alt2.aspmx.l.google.com
- aspmx2.googlemail.com
- aspmx3.googlemail.com
- alt1.aspmx.l.google.com
- aspmx.l.google.com
MX Priorities
- alt2.aspmx.l.google.com: 5
- aspmx.l.google.com: 1
- aspmx2.googlemail.com: 10
- aspmx3.googlemail.com: 10
- alt1.aspmx.l.google.com: 5
A / AAAA Records
- 75.2.60.5 ↩ acd89244c803f7181.awsglobalaccelerator.com
Mail Server IPs
- 172.253.116.27 ↩ dj-in-f27.1e100.net
- 2a00:1450:400b:c02::1b ↩ dj-in-f27.1e100.net
- 172.253.62.26 ↩ bc-in-f26.1e100.net
- 2607:f8b0:4004:c06::1a ↩ bg-in-f26.1e100.net
- 108.177.123.27 ↩ lcscld-in-f27.1e100.net
- 2800:3f0:4003:c0f::1a (no PTR)
- 172.253.116.26 ↩ dj-in-f26.1e100.net
- 2a00:1450:400b:c02::1a ↩ dj-in-f26.1e100.net
- 108.177.123.26 ↩ lcscld-in-f26.1e100.net
SOA Record
Raw SOA
ns-1523.awsdns-62.org awsdns-hostmaster.amazon.com 1 7200 900 1209600 86400
Primary NS (mname)
ns-1523.awsdns-62.org
Admin Email (rname)
awsdns-hostmaster@amazon.com
Serial
1
Refresh
7200s
Retry
900s
Expire
1209600s
Minimum TTL
86400s
Nameservers (NS)
ns-712.awsdns-25.net
ns-77.awsdns-09.com
ns-1523.awsdns-62.org
ns-1818.awsdns-35.co.uk
SPF Record
✓ Strict (-all)
v=spf1 include:_spf.google.com include:sendgrid.net include:spf.mail.intercom.io include:aspmx.pardot.com include:stspg-customer.com include:emsd1.com -all
📊 DNS lookups: 6/10
✓ Hard fail (-all) — strict enforcement
DMARC Record
✗ p=none
v=DMARC1; p=none; rua=mailto:[email protected]
⚠ p=none — monitoring only, no enforcement
📋 SPF alignment: Relaxed
· DKIM alignment: Relaxed
📧 Reports → mailto:[email protected]
DKIM Selectors
✓ 3 found
google._domainkey
s1._domainkey
s2._domainkey
✓ Public key: 216 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
12 records- pardot785633=99843af77ca8b40fd9848ecea960ae5273e6553cf9c8dda7715fd73d99813de3
- slack-domain-verification=FPzPtYFkoNTD4FgWpCfrZqDyt9Ggnfs9ZnZ7YXj7
- status-page-domain-verification=2tdhk6csjrdd
- SPFv=spf1 include:_spf.google.com include:sendgrid.net include:spf.mail.intercom.io include:aspmx.pardot.com include:stspg-customer.com include:emsd1.com -all
- zapier-domain-verification-challenge=030bdedb-2af7-4746-8b8d-bee353091b00
- MS=2F280A3E3195E6CBA8451CEAFFD552779F0EE6DA
- MS=ms48872418
- _cf-custom-hostname.trust.castle.io=8a21ce8d-7e18-4ba3-9e28-83b8553632e3
- atlassian-domain-verification=UY/0TSrRjscHkE1fc4j/5rI7zB9RazHmBuHPYh4ztGtkxj9AAdhqZeTsy8HaQolC
- cursor-domain-verification-ncxc7z=L4W20HEwHElQXqC5Vs4xGzawp
- google-site-verification=kipBgYyk0TD9mitKVzC3tMZxEM7bKlS1i-9wF4K_WMU
- notion-domain-verification=lo1quFPhllHDUZd4Amy1wgpX2kwIyMGy9ToRU20w7aA
Free · No signup required
Add email validation to your forms
Block disposable emails, validate MX records, detect role accounts — unlimited, forever free.
<script src="https://check.verifyswift.com/"></script>
One line of code · Works on any site
See demo & docs
Deep verification
Full email verification for castle.io
SMTP handshake, catch-all detection, custom validation rules, actual deliverability tests, and more.
No credit card required
Get 1,000 Free Credits