Blacklist Checker guide hub
Blacklist Checker guides
Practical guides for Blacklist Checker: examples, troubleshooting steps, and links to the matching DN01 tool.
IP Reputation Before Sending Mail
Scan sending IPs against DNSBL before SMTP warmup and campaigns.
RBL Delisting Workflow — Realistic Steps
From DNSBL listing discovery to operator tickets and prevention.
Check if your IP is blacklisted (without guessing)
How to check whether a public IP appears on DNS blocklists before mail or API traffic breaks.
DNS blacklist check — one tool instead of ten tabs
Online DNSBL lookup for IPs and domains with per-list breakdown.
Spamhaus ZEN lookup — what the codes mean
Student notes on Spamhaus ZEN responses and 127.0.0.x return codes.
Is my domain on a spam list?
How to see if a domain is listed on DBL/SURBL-style lists before email campaigns.
Mail server IP blacklist — why SMTP suddenly fails
Check sending IP against DNSBL before blaming DNS or passwords.
DNSBL and email delivery — connect the dots
Why one DNSBL listing can reject mail and how to read multi-list reports.
SpamCop BL lookup — what listing implies
Notes on SpamCop blocklist checks and delisting workflow.
Domain reputation via DNSBL (not magic scores)
Check domain against public DNS blocklists before buying or migrating.
IP spam reputation — DNSBL edition
Difference between marketing «spam score» and real DNSBL listing.
Removing an IP from a blacklist — realistic steps
The checker shows where you are listed; delisting happens at each list operator.
SURBL multi check for domains
How SURBL-style domain lists differ from IP DNSBL.
SORBS DNSBL — why listings look scary
Reading SORBS results in a multi-list blacklist report.
UCEPROTECT Level 1 — should you panic?
What UCEPROTECT L1 means in a blacklist checker output.
PSBL passive spam blocklist
Quick notes on PSBL and passive DNSBL philosophy.
Mailspike BL — small list, real bounces
Why Mailspike still appears in combined DNSBL checks.
Spamhaus DBL — domain block list explained
When a domain itself is listed, not just the sending IP.
MX IP blacklisted — mail flows through A records too
Check both domain lists and resolved MX host IPs.
Shared hosting IP blacklisted by neighbors
Why your site is fine but email dies on shared IP.
New VPS IP reputation check
Run DNSBL before sending mail from a fresh cloud IP.
Email bouncing because of blacklist
Map SMTP 550 errors to DNSBL listing with an online checker.
Postfix and DNSBL — verify before tuning main.cf
Use an external checker to confirm listings before editing Postfix RBL rules.
Exim rejections vs DNSBL listings
Confirm the IP is listed before chasing Exim ACL ghosts.
Gmail rejecting mail — check DNSBL first
Gmail hides details; external blacklist check gives evidence.
Outlook / M365 and blocklists
Collect DNSBL proof before opening Microsoft support tickets.
PTR, reverse DNS, and blocklists
Why some filters want PTR and how blacklist checks still matter.
Reverse DNS vs DNSBL — different tests
Forward-confirmed reverse DNS is not the same as DNSBL listing.
Dedicated IP — lower risk, not zero
Still run blacklist checks after IP change or provider migration.
New IP already blacklisted?
Inherited reputation on reassigned IPs — verify with DNSBL.
Scan IP against multiple blocklists
Why DN01 runs several DNSBL zones in one request.
DNSBL multi-checker — what to compare
Per-list rows beat a single red/green icon for reports.
Phishing flags on DBL — domain reputation
Domains can be listed for abuse patterns, not only spam.
Malware domain listings in DNSBL
Security teams search domain block status after incidents.
Check a domain before purchase
Run DNSBL on the name before transfer — cheap insurance.
Cloudflare IP and email blacklists
You usually send mail from origin/MX IP, not orange-cloud proxy.
AWS SES IP and DNSBL
Check dedicated SES IPs; shared pools are Amazon's problem until bounces spike.
Office 365 sending IP visibility
Know which IP leaves your tenant when debugging DNSBL.
Transactional email IP warmup
Check DNSBL daily while warming new sending infrastructure.
Newsletter IP reputation reality
Shared ESP IPs can be listed — know your provider's status.
cPanel email blacklisted on shared host
Classic helpdesk ticket — verify IP lists before upgrading plan.
Hosting IP vs email IP
Website and mail may share IP — blacklist check explains bounces.
RBL vs DNSBL — same idea, old names
Terminology for exams and support tickets.
Blacklist API for monitoring
DN01 API tokens for cron jobs that watch sending IPs.
Monitor IP blacklist daily
Automate checks after major sends or IP rotations.
Blacklist check before server migration
New IP or new domain — scan lists before cutover.
IPv6 blacklist checks
IPv6 DNSBL uses nibble reversal — tools should handle it.
IPv4 vs IPv6 on blocklists
Check both when domain resolves dual-stack.
DNSBL query timeouts in reports
A timeout is not a listing — re-run the checker.
Spamhaus query policy — why public DNS matters
Use reputable resolvers; abuse gets blocked.
Free blacklist checker — what «free» should include
Per-list transparency beats a single scary score.
Sender score vs DNSBL listing
Marketing scores and DNSBL answers are different questions.