Domain Intelligence
Last Updated:
Citadel.edu
Safe to Send
Citadel.edu is operated by The Citadel. The domain runs 1 mail exchange and SMTP is responsive, with all three authentication standards in force.
Safe to Send
RISK
10
/100
Low
Verify Mailbox
Verify @citadel.edu emails
Live SMTP handshake against citadel.edu 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
1
Mail exchangers
Mail Exchange (MX) Records for citadel.edu 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.
#0
citadel-edu.mail.protection.outlook.com 52.101.9.0
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 BN1PEPF0000468A.mail.protection.outlook.com Microsoft ESMTP MAIL Service ready at Tue, 12 May 2026 15:10:47 +0000 [08DEADD69A0B5529]
Primary mail server accepted SMTP connection and returned a banner during the live audit.
citadel.edu 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 a mx ip4:3.27.51.160/27 ip4:3.29.194.128/27 ip4:3.99.253.64/27 ip4:3.101.216.128/27 ip4:3.105.224.60 ip4:3.109.187.96 ip4:3.214.204.181 ip4:3.252.108.160/27 ip4:13.39.103.0/27 ip4:13.42.61.32/27 ip4:13.110.208.0/21 ip4:13.110.216.0/22 ip4:13.110.224.0/20 ip4:13.111.0.0/16 ip4:13.211.69.231 ip4:15.222.110.90 ip4:18.99.40.64/27 ip4:18.143.136.64/27 ip4:20.47.149.138 ip4:34.68.104.193 ip4:34.213.216.156 ip4:35.174.145.124 ip4:35.188.64.218 ip4:35.190.247.0/24 ip4:35.202.125.231 ip4:40.92.0.0/15 ip4:40.107.0.0/16 ip4:43.204.62.184 ip4:43.205.150.240/28 ip4:44.211.178.96/27 ip4:52.17.62.50 ip4:52.60.189.48 ip4:52.100.0.0/14 ip4:52.180.90.234 ip4:52.212.19.177 ip4:52.224.142.128 ip4:54.151.112.86 ip4:54.154.213.30 ip4:54.214.32.131 ip4:54.240.70.149 ip4:54.240.70.150 ip4:54.240.71.38/31 ip4:54.240.72.45 ip4:54.240.72.46/31 ip4:54.240.72.48/29 ip4:54.240.80.147 ip4:54.240.80.148/30 ip4:54.240.80.152/29 ip4:54.240.94.192/31 ip4:54.240.94.231 ip4:54.240.94.232/29 ip4:54.240.94.240/31 ip4:54.240.107.23 ip4:54.240.107.24/29 ip4:54.240.107.32/30 ip4:64.18.0.0/20 ip4:64.132.88.0/23 ip4:64.132.92.0/24 ip4:64.233.160.0/19 ip4:66.102.0.0/20 ip4:66.231.80.0/20 ip4:66.249.80.0/20 ip4:68.232.192.0/20 ip4:72.14.192.0/18 ip4:74.125.0.0/16 ip4:104.45.175.206 ip4:104.47.0.0/17 ip4:108.177.8.0/21 ip4:108.177.96.0/19 ip4:128.17.64.0/20 ip4:128.17.128.0/20 ip4:128.17.192.0/20 ip4:128.245.0.0/20 ip4:128.245.64.0/20 ip4:130.211.0.0/22 ip4:134.128.64.0/19 ip4:134.128.96.0/19 ip4:136.147.128.0/20 ip4:136.147.176.0/20 ip4:140.234.0.0/16 ip4:148.105.0.0/16 ip4:149.72.0.0/16 ip4:155.225.6.0/24 ip4:155.225.66.0/23 ip4:155.225.192.0/21 ip4:159.92.157.0/24 ip4:159.92.158.0/24 ip4:159.92.159.0/24 ip4:159.92.160.0/24 ip4:159.92.161.0/24 ip4:159.92.162.0/24 ip4:159.183.0.0/16 ip4:161.71.32.0/19 ip4:161.71.64.0/20 ip4:167.89.0.0/17 ip4:168.245.0.0/17 ip4:172.217.0.0/19 ip4:172.217.32.0/20 ip4:172.217.128.0/19 ip4:172.217.160.0/20 ip4:172.217.192.0/19 ip4:172.253.56.0/21 ip4:172.253.112.0/20 ip4:173.194.0.0/16 ip4:176.31.145.254 ip4:185.131.228.0/25 ip4:185.131.228.128/25 ip4:185.131.229.0/25 ip4:192.254.112.0/20 ip4:198.2.128.0/18 ip4:198.2.177.0/24 ip4:198.2.178.0/23 ip4:198.2.180.0/24 ip4:198.2.186.0/23 ip4:198.21.0.0/21 ip4:198.37.144.0/20 ip4:198.187.196.0/24 ip4:198.245.80.0/20 ip4:199.122.120.0/21 ip4:205.201.128.0/20 ip4:205.201.131.128/25 ip4:205.201.134.128/25 ip4:205.201.136.0/23 ip4:205.201.139.0/24 ip4:207.67.38.0/24 ip4:207.67.98.192/27 ip4:207.126.144.0/20 ip4:208.75.123.0/24 ip4:208.93.120.0/24 ip4:208.93.122.0/24 ip4:208.117.48.0/20 ip4:208.117.49.214 ip4:209.10.173.0/25 ip4:209.43.22.0/28 ip4:209.85.128.0/17 ip4:216.58.192.0/19 ip4:216.239.32.0/19 ip4:216.147.212.20/30 include:_spf0000000.citadel.edu include:publicsafetycloud.net include:spf.protection.outlook.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; pct=100; ruf=mailto:5f5c0597@forensics.dmarc-report.com; rua=mailto:5f5c0597@mxtoolbox.dmarc-report.com; sp=reject; adkim=r; aspf=r
Strict policy. Receivers are instructed to reject any mail that fails SPF or DKIM. The strongest available setting.
citadel.edu Domain Registration WHOIS · Nameservers · Registrar
RegisteredAugust 19, 1993
Last UpdatedApril 15, 2026
ExpiresJuly 31, 2026
Age32 years
TLD.edu
Authoritative Nameservers (6)
- EXTNS3.CLEMSON.EDU
- DNS1.CITADEL.EDU
- EXTNS1.CLEMSON.EDU
- EXTNS2.CLEMSON.EDU
- DNS2.CITADEL.EDU
- DNS3.CITADEL.EDU
Registrant
The Citadel
INFORMATION TECHNOLOGY SERVICES
CHARLESTON, SC, UNITED STATES
Technical Contact
Domain Admin
The Citadel
INFORMATION TECHNOLOGY SERVICES
domains@citadel.edu·CHARLESTON, SC, UNITED STATES·18439536985
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Common Questions About citadel.edu
Is citadel.edu a disposable or temporary email provider?
No. citadel.edu is not a disposable email provider. It is classified as Education Email operated by The Citadel and addresses on citadel.edu are persistent rather than throwaway. Mail sent to a valid citadel.edu mailbox reaches a real recipient.
How do I verify if a citadel.edu email address is valid?
The fastest way to verify a citadel.edu email address is to use our free email checker. Enter any @citadel.edu mailbox at the top of this page and our system performs a real-time SMTP handshake against citadel.edu'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 citadel.edu email exists without sending a message?
Yes. Our real-time email verification API connects directly to citadel.edu'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 citadel.edu mailbox is valid, full, or non-existent. The recipient never receives anything and never sees the check.
What are the MX records for citadel.edu?
citadel.edu currently publishes 1 mail exchange (MX) record. The primary MX is citadel-edu.mail.protection.outlook.com, which is the first server contacted when other mail systems try to deliver email to a citadel.edu 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 citadel.edu.
Does citadel.edu use SPF, DKIM, and DMARC email authentication?
citadel.edu 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 @citadel.edu is genuine, and citadel.edu's DMARC policy of 'reject' instructs receivers how to handle messages that fail those checks.
Why do emails to citadel.edu bounce or get blocked?
Bounces from citadel.edu 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 citadel.edu'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 citadel.edu's receivers trust you.
How can I verify a large list of citadel.edu email addresses?
Our bulk email verifier accepts CSV or TXT uploads with thousands or millions of citadel.edu addresses (or any mix of domains). Every address goes through 30+ checks including SMTP existence, citadel.edu 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 citadel.edu email addresses?
Yes, with normal hygiene. citadel.edu is a legitimate email service and signups from @citadel.edu 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 citadel.edu by default.
What email format does citadel.edu use for usernames?
Most citadel.edu mailboxes follow common patterns like first.last@citadel.edu, firstinitiallast@citadel.edu, or first@citadel.edu, but the actual local-part rules depend on The Citadel. The only reliable way to confirm whether a specific @citadel.edu 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 citadel.edu risk score calculated?
The 0-to-100 risk score for citadel.edu 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 citadel.edu score is recomputed on every audit so it always reflects the live state of the domain.
Is citadel.edu a valid education email domain?
Yes, citadel.edu is a valid educational institution email domain operated by The Citadel. It is used by students, faculty, and staff for academic correspondence.
Is citadel.edu a disposable or temporary email provider?
No, citadel.edu is not a disposable or temporary email provider. It is an institutional email domain. However, student email addresses may be deactivated after graduation depending on the institution's policy.
What mail server does citadel.edu use?
citadel.edu uses mail servers managed by or on behalf of The Citadel. Many universities use Microsoft 365 or Google Workspace for their email infrastructure. Check the MX records section above for details.
Can I send marketing emails to citadel.edu addresses?
You can send emails to citadel.edu addresses with proper consent. Be aware that educational institutions often employ strict spam filtering, and student addresses may become inactive after graduation. Regular list hygiene is recommended.
How do I verify an email address at citadel.edu?
Use BulkEmailChecker to verify citadel.edu addresses. Educational domains may use catch-all configurations or have specific SMTP behaviors. Our tool handles these institution-specific configurations automatically.