Domain Overview
DNS: ✓ 2mo ago
Checker: ✓ 2mo ago
21st.com
Yes
✓ Yes
Proofpoint
No
No
⚠ Yes
No
No
Did you mean: [email protected]
Checked via [email protected]
· 2026-04-01 21:59:43 UTC · ↺ Refresh
MX Hostnames
- mxa-0028ab01.gslb.pphosted.com
- mxb-0028ab01.gslb.pphosted.com
MX Priorities
- mxb-0028ab01.gslb.pphosted.com: 10
- mxa-0028ab01.gslb.pphosted.com: 10
A / AAAA Records
- 45.60.132.143 (no PTR)
- 45.60.122.143 (no PTR)
Mail Server IPs
- 148.163.154.55 ↩ mx0b-0028ab01.pphosted.com
SOA Record
Raw SOA
ns1.a0.impervasecuredns.net hostmaster.21st.com 590475625 14400 1800 172800 1800
Primary NS (mname)
ns1.a0.impervasecuredns.net
Admin Email (rname)
hostmaster@21st.com
Serial
590475625
Refresh
14400s
Retry
1800s
Expire
172800s
Minimum TTL
1800s
Nameservers (NS)
ns1.a2.impervasecuredns.net
ns1.a1.impervasecuredns.net
ns1.a0.impervasecuredns.net
SPF Record
✓ Soft Fail (~all)
v=spf1 include:%{ir}.%{v}.%{d}.spf.has.pphosted.com ~all
📊 DNS lookups: 1/10
~ Soft fail (~all) — moderate enforcement
DMARC Record
✓ Reject
v=DMARC1; p=reject; rua=mailto:[email protected]; ruf=mailto:[email protected];fo=1
✓ Reject — strongest protection
📋 SPF alignment: Relaxed
· DKIM alignment: Relaxed
📧 Reports → mailto:[email protected]
DKIM Selectors
✓ 1 found
k1._domainkey
✓ Public key: 216 chars (valid)
✓ DKIM properly configured for selector: k1
Checked: google, selector1/2, default, mail, dkim, k1, s1/2, zoho, sendgrid, mxvault, amazonses
All TXT Records
29 records- globalsign-domain-verification=ba01260fd1b54abe885fa57e02929380
- s8mp8dptt7rg84g2t9g4x9d0d29jj59p
- js4wqkw66spf5xgsk9jz6zwpktl47q1w
- globalsign-domain-verification=035df092b2033ee0de8d350dc6bba7fe
- facebook-domain-verification=8891glblwcn9dd74oz2zweseshen00
- SPFv=spf1 include:%{ir}.%{v}.%{d}.spf.has.pphosted.com ~all
- 1hsvr9gdl18653xnrmyhbfj8chn7mt5q
- _globalsign-domain-verification=y0sjfQc6jhmDDEAAGHRuW3isRPn-tuic8V1dcaZg53
- google-site-verification=OOGQFPCcD-4qQ7EUtaKf95LQy6VB2lo8JbzC6xiRWvQ
- msl126q7719x926fzm199f52wdrvx7cn
- MS=ms57909519
- mmk94jxhtff5wdk2xst5rptzcyw39q0s
- 47af1437c6c0457fbc8a4165a9ee1299
- globalsign-domain-verification=A3B406F340168B1568CB21854E7CCF26
- xcwzzf1hhqr64l0fhlct7v6px769c75d
- 00de0000000f0yxmay
- MS=ms74761868
- globalsign-domain-verification=9f38f715947cd6806a6c4da69a426cec
- docusign=b4874c46-91c8-4e12-89c4-80c45f3ec374
- globalsign-domain-verification=408f7e6ef92976f5856e147401850a26
- globalsign-domain-verification=e50e0b5f68a0ead33ef980a7743393c8
- docusign=20703969-8fe3-4fb5-b769-ef2ea6969f8f
- _yg7gnuluxud8x0kevnla4d50s1dqb1b
- globalsign-domain-verification=QNggA5G6QQDkhq8HwwSkk3Pq-pS-ocYFv594GxNfmw
- globalsign-domain-verification=f5dd4b7ad55b89795d29b58f7b917565
- k4pcpqj9h185pqgcvprxrm1jbk3tq4nf
- 35ba9f94efe24cb09d4946d485828e23
- globalsign-domain-verification=8d7adb36afdf493ea8d31aec05d524a1
- gtj4j24n7m3b9jvscmkynt2kzc61b1s6
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 21st.com
SMTP handshake, catch-all detection, custom validation rules, actual deliverability tests, and more.
No credit card required
Get 1,000 Free Credits