si.edu - Email Domain Verification & Deliverability Report

Active Government Email
Organization: Smithsonian Institution
Mail Server: Microsoft 365
Verified 4 days ago

Verify email addresses @si.edu. View MX records, mail server configuration, and authentication status for Smithsonian Institution.

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MX Records for si.edu

PriorityMail ServerIP Address
0 si-edu.mail.protection.outlook.com 52.101.10.1
SMTP Status: Responding
SMTP Banner:
220 CH3PEPF00000010.mail.protection.outlook.com Microsoft ESMTP MAIL Service ready at Sun, 8 Mar 2026 14:11:17 +0000 [08DE79E26DE02FF1]

si.edu uses Microsoft 365 mail servers, which means emails are processed through Microsoft 365 infrastructure with their built-in spam filtering and security controls.

Email Authentication for si.edu

SPF Record Pass

v=spf1 ip4:160.111.0.0/16 ip4:67.231.156.100 ip4:67.231.148.101 include:spf1.si.edu include:spf.protection.outlook.com include:mailsenders.netsuite.com -all
Authorized Senders:
spf1.si.edu spf.protection.outlook.com mailsenders.netsuite.com

SPF (Sender Policy Framework) specifies which mail servers are authorized to send email on behalf of si.edu.

DMARC Record Reject

v=DMARC1; p=reject; fo=1; rua=mailto:5e661d18@mxtoolbox.dmarc-report.com,mailto:dmarc@si.edu; ruf=mailto:5e661d18@forensics.dmarc-report.com,mailto:dmarc@si.edu; adkim=r; aspf=r; pct=100;

Policy applied to: 100% of emails

DMARC (Domain-based Message Authentication) tells receiving servers what to do with emails that fail authentication checks.

DKIM Found

DKIM signatures were detected for si.edu, confirming that this domain cryptographically signs outgoing emails.

Authentication Summary: si.edu has full email authentication configured with SPF, DMARC, and DKIM. This provides strong protection against email spoofing and phishing. Emails sent from this domain are well-authenticated and likely to have high deliverability.

WHOIS & Domain Information

Registration Details

Domain
si.edu
TLD
.edu
Created
1992-06-19
Updated
2026-01-13
Expires
2027-07-31
Domain Age
33 years

Registrar

Registrant Contact

Name
Smithsonian Institution
Location
Herndon, VA, UNITED STATES

Technical Contact

Name
Joseph Johnston Smithsonian Institution
Location
Herndon, VA, UNITED STATES

Name Servers

  • A9-64.AKAM.NET
  • A1-88.AKAM.NET
  • A26-66.AKAM.NET
  • A28-65.AKAM.NET
  • A11-67.AKAM.NET
  • A24-67.AKAM.NET

Email Verification for si.edu Government Addresses

The Smithsonian Institution (si.edu) is the world's largest museum, education, and research complex, comprising 21 museums, the National Zoo, and numerous research facilities. Founded in 1846 and headquartered in Washington, D.C., the Smithsonian is a federally funded institution.

The Smithsonian implements email authentication with SPF, DKIM, and DMARC. As a prominent federal institution, the Smithsonian maintains robust email security.

The si.edu mail servers do not function as catch-all. Recipients are validated and invalid addresses rejected. Government-affiliated security standards apply.

Email delivery to si.edu requires authentication compliance with SPF, DKIM, and DMARC.

How to Verify si.edu Email Addresses

Need to check if an email address at si.edu actually exists before you send to it? BulkEmailChecker performs deep SMTP-level validation, connecting directly to si.edu's mail servers to confirm the mailbox is real, active, and able to receive your message. No test email is ever sent, so your sender reputation stays protected.

Verify a Single si.edu Email
Use BulkEmailChecker's free email verification tool to instantly validate any si.edu address. You'll get a complete deliverability report including mailbox existence, catch-all detection, disposable domain flagging, and risk scoring, all in under 3 seconds.

Verify a List of si.edu Emails in Bulk
Have a mailing list full of si.edu addresses? Upload your CSV or TXT file to BulkEmailChecker and verify thousands of email addresses in minutes. Our bulk verification engine runs 30+ checks per address including syntax validation, DNS resolution, SMTP handshake, and spam trap detection. Clean your list before every campaign to keep bounce rates below 2% and protect your sender score. See bulk pricing.

Verify si.edu Emails via API in Real-Time
Building a signup form, CRM integration, or lead capture system? BulkEmailChecker's real-time verification API validates si.edu email addresses at the point of entry, blocking invalid, disposable, and risky addresses before they enter your database. Integrate with a single API call and prevent bad data at the source.

Frequently Asked Questions

Yes, si.edu is a valid official government email domain operated by Smithsonian Institution. It is used by government employees and officials for official correspondence.
No, si.edu is not a disposable or temporary email provider. It is an official government domain used for legitimate government communications and operations.
si.edu uses mail servers managed by Smithsonian Institution. Check the MX records section above for specific server details and authentication configuration.
Yes, si.edu addresses accept incoming email. Government mail servers typically enforce strict spam filtering, authentication checks (SPF, DKIM, DMARC), and content scanning. Ensure your sending domain is properly authenticated.
Use BulkEmailChecker to verify si.edu addresses. Government domains may have specific SMTP behaviors including greylisting and strict rate limiting. Our tool handles these provider-specific configurations automatically.
The fastest and most accurate way to verify a si.edu email address is to use BulkEmailChecker's free email verification tool. Simply enter the full email address and our system performs SMTP-level validation by connecting directly to si.edu's mail servers. You'll get instant results showing whether the mailbox exists, is deliverable, and is safe to send to, all without sending a single email.
Yes. BulkEmailChecker uses SMTP verification to check if a si.edu mailbox exists without ever delivering an email. Our system connects to the domain's mail server, performs an SMTP handshake, and queries the mail server to confirm whether the recipient address is valid. This process is completely invisible to the email recipient and does not affect your sender reputation.
Sending to invalid email addresses causes hard bounces, which directly damage your sender reputation. Internet Service Providers (ISPs) and email providers track your bounce rate, and if it exceeds 2%, your emails may start landing in spam folders or get blocked entirely. Verifying si.edu addresses with BulkEmailChecker before sending prevents bounces and keeps your deliverability high.
BulkEmailChecker's bulk verification service lets you upload a CSV or TXT file containing thousands of si.edu email addresses and verify them all at once. Each address goes through 30+ verification checks including syntax validation, DNS/MX lookup, SMTP verification, disposable domain detection, and spam trap identification. Results are typically ready within minutes and can be downloaded as a clean, verified list.
Email verification is the process of confirming that an email address is real, properly formatted, and capable of receiving messages. It matters because sending to invalid addresses causes bounces, damages your sender reputation, wastes marketing budget, and can get your sending IP blacklisted. BulkEmailChecker verifies addresses at the SMTP level, the most accurate method available, ensuring your emails reach real people.
MX (Mail Exchange) records are DNS entries that specify which mail servers are responsible for receiving email for a domain. When you send an email, your mail server looks up the recipient domain's MX records to find where to deliver the message. If a domain has no MX records, it cannot receive email. BulkEmailChecker checks MX records as part of every verification to confirm the domain is configured for email delivery.
A catch-all (or accept-all) domain is configured to accept email sent to any address at that domain, regardless of whether the specific mailbox exists. This makes it harder to verify individual addresses because the server always responds positively. BulkEmailChecker detects catch-all configurations and flags them in verification results so you can make informed decisions about sending to those addresses.
Yes. BulkEmailChecker offers a real-time email verification API that you can integrate into signup forms, CRM systems, lead capture tools, and any application that collects email addresses. The API validates addresses at the point of entry, blocking invalid, disposable, and risky emails before they enter your database. Integration takes just a single API call with response times under 3 seconds.

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