mail21.cc - Email Domain Verification & Deliverability Report

Risky Disposable Email
Mail Server: amazonaws.com
Verified 6 days ago

Real-time verification data for mail21.cc. View MX records, SPF/DKIM/DMARC authentication, and server deliverability status.

This is a known disposable/temporary email domain. Emails sent to this domain are typically discarded. We recommend blocking this domain on signup forms to prevent fake registrations.
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MX Records for mail21.cc

PriorityMail ServerIP Address
10 inbound-smtp.us-east-1.amazonaws.com 44.210.166.32
SMTP Status: Responding
SMTP Banner:
220 inbound-smtp.us-east-1.amazonaws.com ESMTP Amazon SES fSwSFzPla3INdWY1ICH2

mail21.cc uses amazonaws.com mail servers, which means emails are processed through amazonaws.com infrastructure with their built-in spam filtering and security controls.

Email Authentication for mail21.cc

SPF Record Pass

v=spf1 -all

SPF (Sender Policy Framework) specifies which mail servers are authorized to send email on behalf of mail21.cc.

DMARC Record Reject

v=DMARC1; p=reject; fo=1; ri=3600; rua=mailto:admin@MAIL21.CC; ruf=mailto:admin@MAIL21.CC

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

DKIM Not Detected

DKIM detection is limited from external scanning. The domain may use DKIM with selectors not covered by our scan.

Authentication Summary: mail21.cc has SPF and DMARC configured. This provides good protection against email spoofing. Senders can expect reliable email delivery to this domain.

WHOIS & Domain Information

Registration Details

Domain
mail21.cc
TLD
.cc
Created
2020-04-17
Updated
2025-03-16
Expires
2026-04-17
Domain Age
5 years

Registrar

Name
CSC Corporate Domains, Inc.
IANA ID
299

Name Servers

  • ERIC.NS.CLOUDFLARE.COM
  • KAY.NS.CLOUDFLARE.COM

Disposable Email Domain Information

mail21.cc is flagged as a disposable or temporary email domain. These domains provide throwaway email addresses that expire after a short period. They are commonly used to bypass email verification on signup forms, which can lead to fake accounts, inflated user counts, and degraded sender reputation.

Block This Domain:
// PHP Example: Block disposable emails $disposable_domains = ['mail21.cc']; $email_domain = substr(strrchr($email, "@"), 1); if (in_array(strtolower($email_domain), $disposable_domains)) { // Reject the signup echo "Disposable email addresses are not allowed."; }

Tip: Use BulkEmailChecker's API to automatically detect and block disposable emails in real-time, without maintaining your own blocklist.

How to Verify mail21.cc Email Addresses

Need to check if an email address at mail21.cc actually exists before you send to it? BulkEmailChecker performs deep SMTP-level validation, connecting directly to mail21.cc'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 mail21.cc Email
Use BulkEmailChecker's free email verification tool to instantly validate any mail21.cc 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 mail21.cc Emails in Bulk
Have a mailing list full of mail21.cc 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 mail21.cc Emails via API in Real-Time
Building a signup form, CRM integration, or lead capture system? BulkEmailChecker's real-time verification API validates mail21.cc 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.

Warning: mail21.cc is a Disposable Domain
This domain provides temporary throwaway inboxes that expire within minutes or hours. Emails sent to mail21.cc addresses will never be read. BulkEmailChecker automatically flags and blocks disposable domains like this in both our bulk verifier and real-time API, protecting your list quality and sender reputation.

Frequently Asked Questions

While mail21.cc functions as an email domain, it is classified as a disposable or temporary email service. Emails sent to mail21.cc addresses are short-lived and should not be trusted.
Yes, mail21.cc is a known disposable email provider. Addresses on this domain are temporary and should be blocked in registration forms to prevent fake signups.
mail21.cc operates its own temporary mail infrastructure designed for disposable email addresses. Check the MX records section for details.
No, you should not send marketing emails to mail21.cc addresses. Disposable addresses are temporary and will stop functioning. Sending to these domains wastes resources.
While mail21.cc addresses may pass SMTP verification, they should be flagged and rejected. Use BulkEmailChecker disposable domain detection to block mail21.cc automatically.
The fastest and most accurate way to verify a mail21.cc 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 mail21.cc'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 mail21.cc 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 mail21.cc 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 mail21.cc 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.
Yes, mail21.cc is identified as a disposable email domain. Addresses on this domain are temporary and typically expire within minutes to hours. Emails sent to these addresses will not be read. BulkEmailChecker automatically detects and flags disposable domains in both single and bulk verification, helping you block fake signups and protect your mailing list quality.
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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