---
title: "How to: Whitelist a hostname in ConfigServer Security and Firewall (CSF) "
slug: "how-to-whitelist-a-hostname-in-configserver-security-and-firewall-csf"
updated: 2026-04-13T04:26:58Z
published: 2026-04-13T04:26:58Z
canonical: "docs.serversaustralia.com.au/how-to-whitelist-a-hostname-in-configserver-security-and-firewall-csf"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.serversaustralia.com.au/llms.txt
> Use this file to discover all available pages before exploring further.

# How to: Whitelist a hostname in ConfigServer Security and Firewall (CSF)

If your server has ConfigServer Security and Firewall installed (CSF), then you may find it necessary to whitelist a hostname as opposed to an IP address.

CSF has a file specifically for allowing hostnames called "**csf.dyndns**". Fully Qualified Domain Names (FQDN) are checked at a configurable interval of seconds, to poll for a change in the IP address.

> [!WARNING]
> Please note:
> 
> This will require root access via SSH or console and some command line knowledge to complete.

![Configuration settings for ConfigServer Security and Firewall displayed in a text editor.](https://cdn.document360.io/d809f158-d4f4-47ff-83d4-18d9c9f7a04d/Images/Documentation/Screenshot 2026-03-23 172051.png)

## To whitelist a hostname:

1. SSH to the server
2. Open the file "**/etc/csf/csf.dyndns**" in your preferred text editor and add the hostname.
3. Save and exit the file.
4. Open the file "**/etc/csf/csf.conf**" and set: DYNDNS = "300" (which would check for IP updates every 5 minutes). *Note: If you want the activity of the IP also ignored, set DYNDNS_IGNORE = "1"*
5. Restart the firewall. *You can do this via the CSF interface inside of WHM or by using the command “****csf -r****”*

That's it. The hostnames in **csf.dyndns** will automatically be allowed and the rules will refresh every 5 minutes.