Continuous IP Blocklist Monitoring
Know the moment your mail IPs or domains land on Spamhaus, Barracuda, SpamCop, or any of 7 major DNS blocklists.
Are Your Domains Blocklisted?
Check your IPs and domains against major DNS blocklists from a single dashboard.
| Target | Status | Listed On | Last Checked |
|---|---|---|---|
| mail.acme-corp.com | Clean | 0 of 7 | 3 hours ago |
| 203.0.113.10 | Listed | 2 of 7 | 3 hours ago |
| smtp.acme-corp.com | Clean | 0 of 7 | 6 hours ago |
| 198.51.100.25 | Listed | 1 of 7 | 3 hours ago |
Instant Blocklist Notifications
When your IP or domain appears on a blocklist, every hour counts. Metric Tower alerts you through your existing notification channels so you can start the delisting process immediately.
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Email -- Blocklist alerts delivered to team admins with provider details
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Slack -- Real-time listing notifications in your security ops channel
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PagerDuty -- Critical blocklist events escalated through your incident workflow
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Webhooks -- Push blocklist events to any HTTP endpoint for automation
New Blocklist Listing
4 minutes ago
203.0.113.10 is now listed on Spamhaus ZEN and Barracuda.
Resolves from: mail.acme-corp.com | Previous status: Clean
Protect Your Email Reputation
A single blocklist entry can tank your email deliverability overnight. Catch it early.
7 DNSBL Providers
Checks against Spamhaus ZEN, Barracuda, SpamCop, CBL, Spamhaus DBL, SURBL, and URIBL. The major lists that matter for email deliverability.
Automatic IP Resolution
Add a domain and Metric Tower automatically resolves the A record and checks the underlying IP against IP-based blocklists. No manual IP lookup required.
Listing & Delisting Alerts
Get notified the moment your IP or domain is newly listed on a blocklist, and again when it is removed. No surprises.
Continuous Blocklist Surveillance
Automated checks, historical tracking, and multi-channel alerts keep your infrastructure clean.
Daily Scheduled Checks
Automated blocklist checks run daily so you catch new listings early. The sooner you know about a listing, the faster you can request delisting and restore deliverability.
Historical Tracking
Track listing and delisting events over time. See which blocklists flag your infrastructure most often and identify patterns that indicate a compromised sender or relay.
Email Deliverability Context
Pair blocklist monitoring with Metric Tower's email security scanner (SPF, DKIM, DMARC checks) for a complete picture of your domain's email health. One platform for everything.
DNSBL Protocol
Uses the standard DNSBL reverse-IP lookup protocol for accurate, fast checks. Each provider is queried independently so you see exactly which lists flag your infrastructure.
Check if Your Domains Are Blocklisted
Monitor your mail servers and sending IPs against 7 major DNS blocklists. Get alerted the moment you are listed so you can request delisting before your email deliverability suffers.