Knowledgebase

Overview

This article provides instructions for rejecting incoming mail from a specific IP network or subnet within Warden. By configuring client access rules using CIDR notation, administrators can effectively block traffic from designated networks.

Note: For organizations that utilize multiple subnets, it is recommended to configure scoring rules based on their Autonomous System Number (ASN) rather than individual CIDR blocks. Refer to the ASN Scoring Guide for detailed implementation steps.

Prerequisites

• Administrative access to the Warden management interface.
• The CIDR notation or decimal subnet mask of the network you intend to block.

Configuration Procedure

1. Navigate to Warden > Settings > Mail Server Access > Client Access.
2. In the client access grid, click the Add button.
3. Enter the target network's CIDR notation in the pattern field.
4. Set the action to REJECT - Reject the request.
5. Click Submit to apply and save the rule.

Verification & Logging

Once the rule is active, rejected connection attempts will be recorded in the system logs. To review blocked traffic, navigate to Warden > Logs > Reject log.

CIDR Subnet Reference

Use the following tables to convert decimal subnet masks to CIDR notation when configuring access rules.

IPv4

IPv6

Troubleshooting & Common Issues

• Rule Not Applying: Verify that the CIDR notation is entered correctly without spaces or trailing slashes. Ensure the action is explicitly set to REJECT - Reject the request.
• Missing Log Entries: Confirm that the rejecting server is actively attempting to connect during your monitoring window. Logs only populate when a connection attempt matches the configured pattern.