---
title: "DNSBL Monitoring"
description: "Monitor the reputation of your IP addresses on blocklists."
---

<Callout type="warn">
**Status: Lab**
This feature is currently in the **Lab phase**. This means we are still actively optimizing intervals and the selection of lists.
</Callout>

DNSBL (DNS-based Blocklist) Monitoring regularly checks whether your server's IP address is listed on one of the known "Blacklists" (Blocklists/RBLs). Being listed on such a list often has serious consequences for email delivery (mails land in spam or are rejected).

## How it works

We use our own open-source engine **[uptimeify-dnsbl](https://www.npmjs.com/package/uptimeify-dnsbl)** to check your IP address against over 50 international spam databases.

### Check Interval
Currently, we perform the check **every 180 minutes (3 hours)**.

- **Reason**: DNSBL operators often block excessive queries ("Rate Limiting"). A 3-hour rhythm is a good compromise between timeliness and "Good Citizenship" towards list operators.
- *Note*: If there is a real need for more frequent checks, please contact us.

## What happens if a match is found?

If we find your IP on a list (e.g., Spamhaus, Barracuda, SORBS):

1. **Notification**: You receive an alert via your configured channels.
2. **Details**: We show you the specific reason (e.g., "Listed in SBL" or "Dynamic IP Range").
3. **Solution**: Where available, we provide a direct **Delisting Link** through which you can request removal from the list operator.

## Supported Lists

We query a curated list of reliable providers. A complete overview can be found on the page [Used Lists](/monitoring/monitoring-types/dnsbl/lists).