o2online.de - Email Domain Verification & Deliverability Report

Active ISP Email Provider
Organization: O2 Germany
Mail Server: o2online.de
Verified 4 days ago

Real-time verification data for o2online.de. View MX records, SPF/DKIM/DMARC authentication, and server deliverability status.

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MX Records for o2online.de

PriorityMail ServerIP Address
10 mx.o2online.de 91.136.8.194
100 mx2c52.megamailservers.eu 91.136.8.195
110 mx3c52.megamailservers.eu 91.136.8.196
120 mx4c52.megamailservers.eu 91.136.8.197
SMTP Status: Responding
SMTP Banner:
220 mail98c50.megamailservers.eu ESMTP Sendmail 8.14.9/8.13.1; Wed, 11 Mar 2026 08:11:04 +0000

o2online.de uses o2online.de mail servers, which means emails are processed through o2online.de infrastructure with their built-in spam filtering and security controls.

Email Authentication for o2online.de

SPF Record Pass

v=spf1 ip4:82.113.101.0/24 ip4:212.23.125.184 ip4:46.28.184.125 include:spf.mail.telefonica.de include:spfc50.megamailservers.eu include:spf.mailjet.com -all
Authorized Senders:
spf.mail.telefonica.de spfc50.megamailservers.eu spf.mailjet.com

SPF (Sender Policy Framework) specifies which mail servers are authorized to send email on behalf of o2online.de.

DMARC Record None

v=DMARC1; p=none; rua=mailto:dmarc@report.mail.telefonica.de

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: o2online.de 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
o2online.de
TLD
.de
Updated
2025-06-17

Registrar

Name Servers

  • ns1.o2online.de
  • ns2.o2online.de
  • ns3.o2online.de

About o2online.de

o2online.de is the email domain for O2 Germany, one of Germany's major mobile telecommunications operators. O2 is operated by Telefonica Deutschland and provides mobile, broadband, and DSL services to millions of German customers. Email accounts on o2online.de are available to O2 internet subscribers.

o2online.de supports SPF, DKIM, and DMARC authentication through Telefonica Deutschland infrastructure. As a major German telecom provider, O2 enforces strict authentication standards for inbound email.

The o2online.de mail servers perform thorough recipient validation and apply comprehensive spam filtering with reputation scoring, content analysis, and rate limiting.

For delivery to o2online.de, authenticate with SPF and DKIM, maintain clean lists, and comply with German telecommunications law (TKG) and GDPR. O2 is strict about sender reputation, so gradual IP warmup is recommended.

How to Verify o2online.de Email Addresses

Need to check if an email address at o2online.de actually exists before you send to it? BulkEmailChecker performs deep SMTP-level validation, connecting directly to o2online.de'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.

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Use BulkEmailChecker's free email verification tool to instantly validate any o2online.de 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.

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Verify o2online.de Emails via API in Real-Time
Building a signup form, CRM integration, or lead capture system? BulkEmailChecker's real-time verification API validates o2online.de 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, o2online.de is a valid email domain operated by O2 Germany (Telefonica Deutschland), one of Germany's major mobile and internet providers serving millions of customers.
No, o2online.de is not a disposable or temporary email service. It is a permanent ISP email domain provided by O2 Germany to its internet and mobile subscribers.
o2online.de uses mail servers managed by Telefonica Deutschland infrastructure. The MX records direct inbound email to O2-operated gateways with comprehensive filtering systems.
You can send marketing emails to o2online.de addresses with valid opt-in consent. Authenticate with SPF and DKIM, comply with German telecom law and GDPR, and maintain low complaint rates.
You can verify an o2online.de email address using an email verification service that checks MX records and performs SMTP-level validation to confirm the mailbox is active.
The fastest and most accurate way to verify a o2online.de 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 o2online.de'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 o2online.de 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 o2online.de 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 o2online.de 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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