Domain Intelligence
Last Updated:
Mountsinai.org
Safe to Send
Mountsinai.org is operated by Mount Sinai Health System. The domain runs 10 mail exchanges and SMTP is responsive, with all three authentication standards in force.
Safe to Send
RISK
5
/100
Low
Verify Mailbox
Verify @mountsinai.org emails
Live SMTP handshake against mountsinai.org mail servers. No email is sent. 10 free per day, no signup.
Trusted by 400,000+ senders
4.9/5
From 8,500+ verified reviews
We had a sender reputation crisis after a list import went badly. Used the bulk verifier to scrub everything, then plugged the API into our signup form. Took deliverability from 73% to 96% over six weeks. Sarah Knowles · Email Marketing Lead
SOC 2 Type II
GDPR
CCPA
99.7% Accuracy
Disposable
No
Persistent addresses, not throwaway
SMTP Live
Yes
Mail server responds to SMTP handshake
MX Records
10
Mail exchangers
Mail Exchange (MX) Records for mountsinai.org Mail Exchange records. They tell other mail servers which hosts are responsible for receiving email at this domain, in priority order. Lower priority numbers are tried first.
#10
smtp-agent02.mountsinai.org 146.203.148.112
Reachable
#10
smtp-agent03.mountsinai.org 146.203.148.113
Reachable
#10
smtp-agent05.mountsinai.org 146.203.148.115
Reachable
#10
smtp-agent06.mountsinai.org 146.203.148.116
Reachable
#10
smtp-agent01.mountsinai.org 146.203.148.111
Reachable
#10
smtp-agent04.mountsinai.org 146.203.148.114
Reachable
#20
smtp-agent11.mountsinai.org 159.123.236.111
Reachable
#20
smtp-agent12.mountsinai.org 159.123.236.112
Reachable
#20
smtp-agent14.mountsinai.org 159.123.236.114
Reachable
#20
smtp-agent13.mountsinai.org 159.123.236.113
Reachable
SMTP Handshake
Simple Mail Transfer Protocol. We open a live SMTP connection to the primary MX and read the greeting banner. A response confirms the mail server is alive and accepting connections.
Responsive
BANNER220 smtp-agent02.mountsinai.org ESMTP Mon, 11 May 2026 14:10:24 -0400
Primary mail server accepted SMTP connection and returned a banner during the live audit.
mountsinai.org Email Authentication SPF · DKIM · DMARC
SPF
Sender Policy Framework. A DNS record listing which servers are allowed to send mail for this domain. Receivers reject or flag mail from unauthorized servers.
Pass
TXTv=spf1 ip4:40.84.22.152 ip4:205.201.24.98 ip4:68.233.77.16 ip4:146.203.0.0/16 ip4:159.123.0.0/16 ip4:68.233.76.14 ip4:69.72.33.74 ip4:20.246.85.68 exists:_spf.%{i}.bold.chat include:spf.protection.outlook.com include:spf_c.oraclecloud.com include:_spf.tinyemail.com ~all
Authorized senders are defined and pass SPF policy.
DKIM
DomainKeys Identified Mail. The sending server cryptographically signs outbound mail with a private key, and receivers verify the signature using a public key in DNS.
Pass
SELECTORDetected via standard selectors
A DKIM signature was detected. Outbound mail from this domain can be cryptographically verified.
DMARC
Domain-based Message Authentication, Reporting & Conformance. Tells receivers what to do when SPF or DKIM checks fail: none, quarantine, or reject.
Reject
TXTv=DMARC1; p=reject; fo=1; rua=mailto:dmarc_rua@emaildefense.proofpoint.com; ruf=mailto:dmarc_ruf@emaildefense.proofpoint.com
Strict policy. Receivers are instructed to reject any mail that fails SPF or DKIM. The strongest available setting.
mountsinai.org Domain Registration WHOIS · Nameservers · Registrar
RegistrarNetwork Solutions, LLC
IANA ID2
RegisteredFebruary 23, 1996
Last UpdatedDecember 26, 2025
ExpiresFebruary 24, 2031
Age30 years
TLD.org
Authoritative Nameservers (6)
- A1-223.AKAM.NET
- A11-66.AKAM.NET
- A18-67.AKAM.NET
- A4-64.AKAM.NET
- A8-65.AKAM.NET
- A9-66.AKAM.NET
Registrant
andrew.pizzimenti@mssm.edu·NEW YORK, NY, UNITED STATES·12122414929
Technical Contact
hostmaster, mssm
hostmaster@mssm.edu·16466055478
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Common Questions About mountsinai.org
Is mountsinai.org a disposable or temporary email provider?
No. mountsinai.org is not a disposable email provider. It is classified as Corporate Email operated by Mount Sinai Health System and addresses on mountsinai.org are persistent rather than throwaway. Mail sent to a valid mountsinai.org mailbox reaches a real recipient.
How do I verify if a mountsinai.org email address is valid?
The fastest way to verify a mountsinai.org email address is to use our free email checker. Enter any @mountsinai.org mailbox at the top of this page and our system performs a real-time SMTP handshake against mountsinai.org's mail servers, confirming whether the mailbox exists, is reachable, and is safe to send to. No email is ever delivered during the check.
Can I check if a mountsinai.org email exists without sending a message?
Yes. Our real-time email verification API connects directly to mountsinai.org's mail server, opens an SMTP session, and queries the mailbox using the RCPT TO command without ever transmitting an actual email. The server's response confirms whether the mountsinai.org mailbox is valid, full, or non-existent. The recipient never receives anything and never sees the check.
What are the MX records for mountsinai.org?
mountsinai.org currently publishes 10 mail exchange (MX) records. The primary MX is smtp-agent02.mountsinai.org, which is the first server contacted when other mail systems try to deliver email to a mountsinai.org address. The full list with priorities and IP addresses is in the MX Records panel above. MX records tell sending servers where to route email for mountsinai.org.
Does mountsinai.org use SPF, DKIM, and DMARC email authentication?
mountsinai.org enforces all three email authentication standards: SPF, DKIM, and DMARC (policy: reject). This is the gold-standard configuration. It means receivers can verify that mail claiming to come from @mountsinai.org is genuine, and mountsinai.org's DMARC policy of 'reject' instructs receivers how to handle messages that fail those checks.
Why do emails to mountsinai.org bounce or get blocked?
Bounces from mountsinai.org usually fall into three buckets: the mailbox doesn't exist (5xx user unknown), the inbox is full, or your sending domain isn't authenticated to mountsinai.org's satisfaction. The fastest fix is to run each address through a free email verifier before you send, and to make sure your own SPF, DKIM, and DMARC are configured correctly so mountsinai.org's receivers trust you.
How can I verify a large list of mountsinai.org email addresses?
Our bulk email verifier accepts CSV or TXT uploads with thousands or millions of mountsinai.org addresses (or any mix of domains). Every address goes through 30+ checks including SMTP existence, mountsinai.org catch-all detection, role-account detection, and disposable-domain matching. Results typically come back within minutes and previously-failed addresses on your blacklist are reprocessed for free. For continuous high-volume needs, see our unlimited email verification API.
Is it safe to accept signups from mountsinai.org email addresses?
Yes, with normal hygiene. mountsinai.org is a legitimate email service and signups from @mountsinai.org behave like any other real user. Pipe each address through a real-time email verifier API at the moment of signup to catch typos and dead mailboxes, but there is no need to block mountsinai.org by default.
What email format does mountsinai.org use for usernames?
Most mountsinai.org mailboxes follow common patterns like first.last@mountsinai.org, firstinitiallast@mountsinai.org, or first@mountsinai.org, but the actual local-part rules depend on Mount Sinai Health System. The only reliable way to confirm whether a specific @mountsinai.org address exists is to run it through a free email verification tool. Guessing patterns will produce a high bounce rate and damage your sender reputation.
How is the mountsinai.org risk score calculated?
The 0-to-100 risk score for mountsinai.org combines disposable-domain classification, mail-server reachability, MX record presence and depth, SPF / DKIM / DMARC enforcement, DMARC policy strength, SMTP banner response, and domain age. Lower scores mean safer to send to. Disposable domains are pinned at the high end of the scale. The mountsinai.org score is recomputed on every audit so it always reflects the live state of the domain.
Is mountsinai.org a valid corporate email domain?
Yes, mountsinai.org is the official corporate email domain for Mount Sinai Health System. It is used for internal business communications and is not available for public registration.
Is mountsinai.org a disposable or temporary email provider?
No, mountsinai.org is a corporate email domain belonging to Mount Sinai Health System, used exclusively by employees and authorized personnel.
What mail server does mountsinai.org use?
mountsinai.org uses enterprise-grade mail infrastructure. Check the MX records section above for specific mail server details.
Can I send marketing emails to mountsinai.org addresses?
B2B marketing to mountsinai.org requires proper consent. Corporate domains may use catch-all configurations, so verify individual addresses before sending.
How do I verify an email address at mountsinai.org?
Corporate domains like mountsinai.org may use catch-all configurations. Use BulkEmailChecker's advanced verification to detect catch-all behavior.