Nagios XI - LDAP / Active Directory - Import Users Certificate Issues

Problem Description

When using the "LDAP / Active Directory Import Users" component in Nagios XI you may receive an error like the following when attempting to login:

Unable to authenticate: TLS error-8179:Peer's Certificate issuer is not recognized.

Issues like these can occur when the certificate you've added to Nagios XI is for a root CA when a subordinate CA is what actually issued the certificate, this subordinate CA certificate will also need to be uploaded.

Resolving the Problem

Delete Certificates

First step is to remove the existing certificates.

• Log into the Nagios XI Web interface

• Navigate to Admin > Users > LDAP/AD Integration

  • Under the Certificate Authority Management section

  • Delete all the existing certificates by clicking the X icon in the Actions column

Ensure Environment Is Correctly Setup

Log into your Nagios XI server in an SSH session and execute the following commands:

mkdir -p /etc/openldap/cacerts
chown apache.nagios /etc/openldap /etc/openldap/cacerts /etc/openldap/certs
chmod 664 /etc/openldap/ldap.conf
chmod 775 /etc/openldap /etc/openldap/certs /etc/openldap/cacerts
sed -i 's/TLS_CACERTDIR/#TLS_CACERTDIR/g' /etc/openldap/ldap.conf
echo "TLS_CACERTDIR /etc/openldap/cacerts" >> /etc/openldap/ldap.conf

The last step is to restart the Apache service using one of the commands below:

RHEL 7 | CentOS 7 | Oracle Linux 7

systemctl restart httpd.service

Debian | Ubuntu 16/18

systemctl restart apache2.service

Add Certificates

Now add all the required CA certificates.

• Log into the Nagios XI Web interface

• Navigate to Admin > Users > LDAP/AD Integration

  • Under the Certificate Authority Management section

  • Click the Add Certificate button

    • Paste the text from your certificate and then click the Add Certificate button

  • Repeat until all the required certificates have been added

Once you have completed the above steps the Import Users functionality will work if the CA certificates match the LDAP / Active Directory they are authenticating against.

Final Thoughts

For any support related questions please visit the Nagios Support Forums at:

http://support.nagios.com/forum/