TestOneMail RBL Live DNSBL

Real-Time Threat Intelligence

Defend Your Mail Server With Live Incident Telemetry.

A high-frequency RFC 5782 DNSBL zone (bl.testonemail.com) aggregating active Postfix & Dovecot SASL brute-force probes, DMARC domain impersonators, and 24/7 Guardian reputation defense.

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Active Listings
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Level 1 (3d)
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Level 2 (14d)
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Level 3 (30d)

Blocklist Lookup

Check an IP on bl.testonemail.com

Enter any IPv4 address to check its current reputation, strike history, and automated expiration.

1. Postfix MTA Integration

Add reject_rbl_client bl.testonemail.com to your smtpd_recipient_restrictions in /etc/postfix/main.cf: 

smtpd_recipient_restrictions =
    permit_mynetworks,
    permit_sasl_authenticated,
    reject_unauth_destination,
    reject_rbl_client bl.testonemail.com

2. Postscreen Integration

If using Postscreen for pre-greeting screening, weight TestOneMail in /etc/postfix/main.cf: 

postscreen_dnsbl_sites =
    zen.spamhaus.org*3,
    b.barracudacentral.org*2,
    bl.testonemail.com*2

3. Command-Line DNS Test

Verify your DNS resolution using the standard RFC 5782 test loopback: 

dig A 2.0.0.127.bl.testonemail.com +short
# Output should return: 127.0.0.2

24/7 Blocklist Guardian

Continuous reputation monitoring for your mail servers. Get alerted immediately the moment your IP appears on any blocklist, with automated 30-minute escalation.

Monitoring Tiers
Tier 1: Standard
Free
  • 12-hour routine scans
  • 1-hour incident escalation
  • 32 DNSBL zones monitored
  • Instant email alert notifications
Popular
Tier 2: Pro
£9 /mo
  • 6-hour routine scans
  • 30-minute incident escalation
  • High-priority DNSBL queue
  • On-demand instant re-scans
Tier 3: Ultimate
£19 /mo
  • 1-hour routine scans
  • 30-minute incident escalation
  • Maximum deliverability defense
  • Unlimited manual scans

Request Delisting or Contest a Listing

Level 1 (transient/first-time offenders) are granted instant self-service delisting with a 30-day cooldown. Repeat offenders or DMARC spoofers are forwarded to the security team for verification.

Fail2ban Client Addon & Log Exporter

Feed blocked attackers directly from your remote mail servers into the TestOneMail RBL network in real time. Features automated log sanitization, password scrubbing, and zero external dependencies.

Official Addon v1.0.0
1-Command Automatic Installer 
curl -sSL https://blacklist.testonemail.com/install.sh | sudo bash -s -- --key sq-rbl-key-9f82a17c4b

Installs /usr/local/bin/testonemail-reporter (Python 3, zero-pip), sets up /etc/testonemail/reporter.json, installs action.d/testonemail.conf, and performs a live connectivity selftest.

2. Enable the Action in Your Jails

Attach testonemail to your active mail jails in /etc/fail2ban/jail.local: 

# /etc/fail2ban/jail.local

[postfix-sasl]
enabled = true
action  = %(known/action)s
          testonemail

[dovecot]
enabled = true
action  = %(known/action)s
          testonemail

[postfix-pregreet]
enabled = true
action  = %(known/action)s
          testonemail

Reload Fail2ban to apply changes immediately: 

sudo fail2ban-client reload
Privacy & Log Scrubbing

Automatically redacts passwords, plain auth strings, base64 hashes, and sensitive credentials from log matches before transmission.

Zero Dependencies

Built on native Python 3 standard library (no pip packages or virtualenvs). Runs cleanly on Debian, Ubuntu, AlmaLinux, Rocky, and RHEL.

Fail-Safe & Non-Blocking

Enforces a strict 5s socket timeout and 5-minute local deduplication cache. Never blocks, delays, or throws errors to Fail2ban.

Manual Component Downloads: