---
title: "SNI Override feature"
slug: "sni-override-feature-for-gullfoss-agent-1"
updated: 2025-08-04T12:57:44Z
published: 2025-08-04T12:57:44Z
---

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

# SNI Override feature

## Introduction

We’ve introduced the **SNI Override** feature to address limitations in our existing DNS and Host Header override options, which do not provide control over the SNI (Server Name Indication) field in the initial TLS handshake. With this enhancement, Catchpoint clients—especially when running non-browser (JS API) and web HTTPS tests that use DNS Override—can now specify a custom SNI value in the TLS "Client Hello" packet. This enables comprehensive monitoring for servers that depend on SNI-based routing and certificate selection.

## Solution

To overcome these failures, you will need to include an **Sni-Override** custom header in the request section for non-transaction tests, or use the `setHeader` command to set a Sni-Override header for an API script.

For example:

**API Script:**

```
setHeader(dns-override:abc.xyz.com, 12.12.15.25);
setHeader("Sni-Override", "abc.xyz.com");
open("https://abc.xyz.com/something");
```

**Request Section:** ![sni1.png](https://cdn.document360.io/cb4af8f9-6751-4fd2-b39c-07aae832badb/Images/Documentation/4402426936333-sni1.png)