Pink PostWhat an email blacklist is
Blacklists (blocklists, DNSBLs) are databases of IP addresses and domains seen sending spam. Mail servers query them through DNS while a message arrives; a listing can mean rejection, spam-folder placement or a higher spam score. There are dozens of lists with very different standards. Some list an IP after a single spam-trap hit; others list whole hosting ranges.
Lists this tool checks
| List | Type | Notes |
|---|---|---|
| Barracuda | IP | Used by Barracuda gateways. |
| SpamCop | IP | Based on user spam reports; entries expire fast. |
| PSBL | IP | Passive spam trap list; easy self-removal. |
| Mailspike | IP | Reputation-based list. |
| UCEPROTECT L1 | IP | Lists single IPs. Levels 2 and 3 list whole ranges and are not used here. |
| s5h | IP | Small spam trap list. |
| DroneBL | IP | Compromised machines and open proxies. |
| NordSpam | IP | Spam trap list. |
| 0spam | IP | Spam trap list. |
| Anonmails | IP | Spam trap list. |
| SEM Backscatter | IP | Servers sending bounce backscatter. |
| NordSpam DBL | Domain | Domains seen in spam. |
| SEM URIBL | Domain | Domains seen in spam message bodies. |
| SEM Fresh | Domain | Domains registered in the last 5 days. Informational, not a penalty. |
Why Spamhaus is not in the results
Spamhaus is the most influential blocklist, but it refuses queries sent through public resolvers such as Cloudflare's 1.1.1.1 and Google's 8.8.8.8, and returns an error code instead of an answer. A browser tool cannot query it honestly, so we leave it out rather than show a false "clean". Check it directly at check.spamhaus.org. URIBL and SURBL apply similar rules.
If you are listed
- Find the cause: a compromised account, a form sending spam, a bad list, or a shared IP from your provider.
- Fix it first: delisting before you fix the cause leads to relisting.
- Request removal on the list's own site. Many lists expire entries automatically after a quiet period.
- Shared IPs: if you send from Google Workspace or Microsoft 365, a listing of their IPs is theirs to handle and rarely affects delivery. Focus on your domain.
Staying off blacklists with outreach
Outreach rarely triggers blocklists when it is personal and low volume. The risks are bad addresses (spam traps hide in scraped lists) and sudden volume spikes. Pink Post checks every address against your blocklist and existing prospects before sending, caps each mailbox per day and hour, warms new mailboxes slowly and pauses a mailbox automatically if bounces pass 5%.