> Source: [sk111134](https://support.checkpoint.com/results/sk/sk111134)

# sk111134 - Kerberos Authentication fails when Web application sends duplicate "WWW-Authenticate: Negotiate" HTTP  headers

| Property | Value |
|----------|-------|
| Solution ID | sk111134 |
| Date Created | 2016-04-23 |
| Last Modified | 2017-04-02 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |
| OS | Gaia |

## Symptoms

- * Kerberos Authentication fails when Web application sends duplicate "WWW-Authenticate: Negotiate" HTTP headers.
* In Trace logs, see that the Web Server sends duplicate Authentication headers: \[CPCVPN_RECEIVED_HEADERS\] \|XX:XX:XX.XXX\|  
  HTTP/1.1 401 Unauthorized  
  Server: Apache-Coyote/1.1  
  \[/CPCVPN_RECEIVED_HEADERS\]  
  \[CPCVPN_INFO/\] \|XX:XX:XX.XXX\| gss_init_sec_context() failed: : No Kerberos credentials available  
  \[CPCVPN_RECEIVED_HEADERS\] \|XX:XX:XX.XXX\|  
  WWW-Authenticate: Negotiate  
  \[/CPCVPN_RECEIVED_HEADERS\]  
  \[CPCVPN_INFO/\] \|XX:XX:XX.XXX\| gss_init_sec_context() failed: : No Kerberos credentials available  
  \[CPCVPN_RECEIVED_HEADERS\] \|XX:XX:XX.XXX\|  
  WWW-Authenticate: Negotiate  
  Content-Length: 348  
  Date: Wed, XX Apr XXX XX:XX:XXGMT  
* Kerberos Ticket is created succesfuly by the KDC (Key Distribution Center).
* HTTPD shows the following entries:  
  WebHandler::configureLibCurl: using KRB5_CONFIG=/opt/CPcvpn-R77/var/krb5.auto.conf  
  Cvpn::WebHandler::curlGotResponseHeader: Setting credentials in Kerberos  
  Cvpn::WebHandler::content: Restart libcurl in order to authenticate  
  \[CVPN_INFO\] getPoolInstance: creating a new LibCurl instance  
  Cvpn::WebHandler::content: Restart libcurl in order to authenticate

## Cause

A limitation in the *Libcurl* code causes the authentication to fail when the duplicate *"WWW-Authenticate: Negotiate"* http headers are sent from the Internal Web Server.

## Solution

This solution requires authentication. Please log in to view the full solution.

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content