Incident
Email Blacklisting: How It Happens and How to Recover
IP blacklisting can happen to any mail server — including those with good sending practices. Shared hosting IPs, compromised accounts, and sudden volume spikes are the most common triggers. Here's how blacklisting happens and how to get removed.
Your IP can land on a blocklist even when you did nothing wrong — shared hosting, a stolen account, or a bad list with spam traps. The impact is immediate: bounces, junk folder, or total silence from major receivers.
How servers get blacklisted
Compromised account: One user account gets phished. The attacker uses it to send thousands of spam messages. The IP gets listed on Spamhaus before the owner even notices.
Shared hosting: Your IP is shared with 50 other customers. One of them sends spam. Everyone on that IP gets blacklisted together.
Volume spike: You send a legitimate bulk campaign after months of low volume. The sudden spike looks like spam. You get listed.
Spam trap hits: Your list contains old addresses that have been converted to spam traps. Every email to them counts as spam.
Impact by blacklist
Recovery steps
- Run DomainPreflight Email tool — identify which lists you're on
- Fix the underlying cause first
- Submit removal requests: Spamhaus (spamhaus.org/removal), SpamCop (auto-expires 24-48 hours after spam stops), Barracuda (barracudacentral.org/lookups)
- Monitor for re-listing
Check if your IP is blacklisted
Open Email tool →FAQ
How do I know if my IP is blacklisted?
Run DomainPreflight Email Deliverability with your sending IP — checks 10+ major blacklists instantly.
How long does blacklist removal take?
Spamhaus: 24-48 hours after request. SpamCop: auto-expires. Barracuda: 12-24 hours after request.
Can I get blacklisted for sending legitimate email?
Yes — sudden volume spikes, old lists with spam traps, or being on a shared IP with a spammer can trigger listing.
What if I'm on a shared IP and someone else caused the listing?
Request a dedicated IP from your sending provider. Shared IPs are a permanent risk for high-volume senders.
Will getting delisted fix my spam folder problem?
If blacklisting was the cause — yes. Run DNS Preflight after delisting to check for other issues.