holtz-architecture.com

Valid Email Server
Domain Lookup › holtz-architecture.com

Domain Overview

DNS: ✓ 2mo ago Checker: ✓ 2mo ago
holtz-architecture.com
Yes
✓ Yes
Outlook
No
No
⚠ Yes
No
No

Checked via [email protected] · 2026-03-20 02:21:19 UTC · ↺ Refresh

MX Hostnames

  • holtzarchitecture-com01c.mail.protection.outlook.com

MX Priorities

  • holtzarchitecture-com01c.mail.protection.outlook.com: 0

A / AAAA Records

  • 217.160.0.23 ↩ 217-160-0-23.elastic-ssl.ui-r.com
  • 2001:8d8:100f:f000::200 ↩ 2001-08d8-100f-f000-0000-0000-0000-0200.elastic-ssl.ui-r.com

Mail Server IPs

  • 52.101.50.13 ↩ mail-mw2pr02cu00605.inbound.protection.outlook.com
  • 52.101.8.42 ↩ mail-dm6pr03cu00402.inbound.protection.outlook.com
  • 52.101.11.13 ↩ mail-sn1pr0501cu00205.inbound.protection.outlook.com
  • 52.101.9.17 (no PTR)
  • 2a01:111:f403:c931:: ↩ mail-sn1pr02cu00100.inbound.protection.outlook.com
  • 2a01:111:f403:c936:: ↩ mail-cy1pr05cu00400.inbound.protection.outlook.com
  • 2a01:111:f403:f90b:: ↩ mail-bn6pr04cu00100.inbound.protection.outlook.com
  • 2a01:111:f403:c946::5 ↩ mail-ch4pr21cu00105.inbound.protection.outlook.com

SOA Record

Raw SOA ns51.1and1.com hostmaster.1and1.com 2016040413 28800 7200 604800 300
Primary NS (mname)
ns51.1and1.com
Admin Email (rname)
hostmaster@1and1.com
Serial
2016040413
Refresh
28800s
Retry
7200s
Expire
604800s
Minimum TTL
300s

Nameservers (NS)

ns51.1and1.com
ns52.1and1.com

SPF Record

✓ Strict (-all)
v=spf1 include:spf.protection.outlook.com -all
📊 DNS lookups: 1/10
✓ Hard fail (-all) — strict enforcement

DMARC Record

✗ Missing

No DMARC record — emails cannot be rejected on auth failure.

DKIM Selectors

✗ None detected

No DKIM records found for common selectors — your provider may use a custom selector name.

Checked: google, selector1/2, default, mail, dkim, k1, s1/2, zoho, sendgrid, mxvault, amazonses

All TXT Records

3 records
  • RTH-8852-OLP
  • SPFv=spf1 include:spf.protection.outlook.com -all
  • v=verifydomain MS=9937802
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 holtz-architecture.com

SMTP handshake, catch-all detection, custom validation rules, actual deliverability tests, and more.

No credit card required
Get 1,000 Free Credits