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A1.at

Safe to Send

A1.at is operated by A1 Telekom Austria. The domain runs 1 mail exchange and SMTP is responsive, with all three authentication standards in force.

Safe to Send
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@a1.at
No email sent No signup Real-time SMTP

Trusted by 400,000+ senders

4.9/5
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Switched after a billing dispute with NeverBounce. Same SMTP results on a 5k test sample. The MX, SPF, DKIM lookup tools are a hidden value-add for debugging client deliverability complaints. James Wexler · Growth Engineer
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 a1.at 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.

1 RECORD
#10
a1-at.mail.protection.outlook.com 52.101.73.16
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 AM4PEPF00027A6A.mail.protection.outlook.com Microsoft ESMTP MAIL Service ready at Wed, 13 May 2026 17:10:04 +0000 [08DEADA73790F92C]
Primary mail server accepted SMTP connection and returned a banner during the live audit.

a1.at Email Authentication SPF · DKIM · DMARC

3/3 PASS
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 ip4:80.120.70.53 ip4:80.95.234.18 ip4:213.33.87.0/27 ip4:195.3.86.128/26 ip4:195.3.86.192/27 include:spf-out.a1.at include:_spf.eventmaker.at include:cust-spf.exacttarget.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. None
TXTv=DMARC1; p=none; rua=mailto:DMARC-rua@a1.at;ruf=mailto:dmarc-ruf@a1.at
Monitoring only. Receivers take no action when SPF or DKIM fails.

a1.at Domain Registration WHOIS · Nameservers · Registrar

WHOIS
RegistrarA1 Telekom Austria AG ( https://nic.at/registrar/16 )
IANA ID1531
Last UpdatedSeptember 24, 2019
TLD.at
Authoritative Nameservers (3)
  • dns1.a1.net
  • dns2.a1.net
  • dns3.a1.net
Registrant
A1 Telekom Austria AG
Wien, AUSTRIA
Technical Contact
Domain Admin
A1 Telekom Austria AG
Linz, AUSTRIA
About this Domain

About a1.at

a1.at is the email domain for A1 Telekom Austria, the largest telecommunications provider in Austria. A1 offers broadband, mobile, and TV services to millions of Austrian customers, and a1.at email accounts are widely used across the country for personal communication.

A1 Telekom Austria supports SPF authentication on the a1.at domain, and outbound messages generally include DKIM signatures. DMARC policies are published at a baseline level. Senders targeting a1.at addresses should ensure proper SPF alignment and valid DKIM signing to maintain inbox placement.

The a1.at mail servers perform standard recipient verification during the SMTP transaction, rejecting messages for unknown mailboxes with a 550 error. Greylisting may be applied to unfamiliar senders, requiring a retry after a short delay. Rate limiting is enforced for high-volume senders.

When sending to a1.at addresses, maintain clean mailing lists and authenticate all messages with SPF and DKIM. Avoid using purchased lists, as spam complaints from A1 users can quickly lead to blacklisting. Warm up new sending IPs gradually and monitor bounce rates closely.

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Common Questions About a1.at

Is a1.at a disposable or temporary email provider?
No. a1.at is not a disposable email provider. It is classified as ISP Email Provider operated by A1 Telekom Austria and addresses on a1.at are persistent rather than throwaway. Mail sent to a valid a1.at mailbox reaches a real recipient.
How do I verify if a a1.at email address is valid?
The fastest way to verify a a1.at email address is to use our free email checker. Enter any @a1.at mailbox at the top of this page and our system performs a real-time SMTP handshake against a1.at'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 a1.at email exists without sending a message?
Yes. Our real-time email verification API connects directly to a1.at'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 a1.at mailbox is valid, full, or non-existent. The recipient never receives anything and never sees the check.
What are the MX records for a1.at?
a1.at currently publishes 1 mail exchange (MX) record. The primary MX is a1-at.mail.protection.outlook.com, which is the first server contacted when other mail systems try to deliver email to a a1.at 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 a1.at.
Does a1.at use SPF, DKIM, and DMARC email authentication?
a1.at enforces all three email authentication standards: SPF, DKIM, and DMARC (policy: none). This is the gold-standard configuration. It means receivers can verify that mail claiming to come from @a1.at is genuine, and a1.at's DMARC policy of 'none' instructs receivers how to handle messages that fail those checks.
Why do emails to a1.at bounce or get blocked?
Bounces from a1.at 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 a1.at'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 a1.at's receivers trust you.
How can I verify a large list of a1.at email addresses?
Our bulk email verifier accepts CSV or TXT uploads with thousands or millions of a1.at addresses (or any mix of domains). Every address goes through 30+ checks including SMTP existence, a1.at 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 a1.at email addresses?
Yes, with normal hygiene. a1.at is a legitimate email service and signups from @a1.at 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 a1.at by default.
What email format does a1.at use for usernames?
Most a1.at mailboxes follow common patterns like first.last@a1.at, firstinitiallast@a1.at, or first@a1.at, but the actual local-part rules depend on A1 Telekom Austria. The only reliable way to confirm whether a specific @a1.at 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 a1.at risk score calculated?
The 0-to-100 risk score for a1.at 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 a1.at score is recomputed on every audit so it always reflects the live state of the domain.
Is a1.at a valid email domain?
Yes, a1.at is a valid and active email domain operated by A1 Telekom Austria, the largest telecom provider in Austria. Email accounts on this domain are used by millions of Austrian residents.
Is a1.at a disposable or temporary email service?
No, a1.at is not a disposable or temporary email service. It is a permanent ISP email domain provided by A1 Telekom Austria to its broadband and mobile customers.
What mail servers does a1.at use?
a1.at uses mail servers managed by A1 Telekom Austria infrastructure. The specific MX records point to A1-operated mail gateways that handle inbound email filtering and delivery for all a1.at mailboxes.
Can I send marketing emails to a1.at addresses?
You can send marketing emails to a1.at addresses only with proper opt-in consent from the recipients. A1 applies spam filtering, so authenticate with SPF and DKIM, honor unsubscribe requests promptly, and comply with Austrian and EU data protection regulations including GDPR.
How do I verify an a1.at email address?
You can verify an a1.at email address using an email verification service that checks MX records, performs SMTP mailbox validation, and confirms the address is deliverable. Real-time verification at signup helps prevent invalid addresses from entering your database.