---
sourceDocument: Australia Security Management
sourceDocumentLink: https://servicenow-prod.fluidtopics.net/r/security-management

 Release :

    - australia

ft:locale :

    - en-US

ft:publication_title :

    - Australia Security Management

ft:clusterId :

    - security

bundleId :

    - security

workflow :

    - Technology


---

# Block list entry exceptions

# Block list entry exceptions for the Check Point NGTP integration {#block-list-exceptions___Toc536438008}

* Release version: Australia
* 
* Updated March 12, 2026
* 
* ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 1 minute to read

There are restrictions for adding Block List entries to Block Lists. If duplicate,
compatibility, or CIDR (Classless Inter-Domain Routing) conflicts exist when you try to add Block
List entries to Block Lists, error messages are displayed that help you resolve these
errors.

## Compatibility exception {#block-list-exceptions___Toc531259075}

Each Block List only accepts entries that are compatible with its observable type. If you
create a Domain Block List and you try to attach an IP address observable to it, an incompatible
error message is displayed. For example, a domain Block List can only accept domain observables,
as illustrated in the following figure.
Figure 1. Block List form with compatibility errors

## Duplication exception {#block-list-exceptions___Toc531259076}

An observable cannot be activated on multiple Block Lists of the same observable type. If a URL observable is already activated on a URL Block List, and you try to activate the same observable on a Phishing URL Block List, a
duplication error message is displayed.

## CIDR (Classless Inter-Domain Routing) exception {#block-list-exceptions___Toc531259077}

If you attempt to attach a single IP address to an allow list, and this IP address is part of a CIDR observable already on a Block list/Allow list, a CIDR conflict error is displayed. This error indicates that the single IP
address is already included on the Block list or allow list as part of the CIDR observable. For example, 192.168.24.25 is part of the CIDR block 192.168.0.0/22.