Nagios Support Forum

For when you want a client to trust a server's self-signed cert

on the client:
openssl s_client -showcerts -servername server -connect server:443 > cacert.pem
note - in the above the server name (or IP address) is required in two places - look for the word server

type "quit", followed by the "ENTER" key

The certificate will have "BEGIN CERTIFICATE" and "END CERTIFICATE" markers.

*** If you want to see the data in the certificate, you can do: "openssl x509 -inform PEM -in certfile -text -out certdata" where certfile is the cert you extracted from logfile. Look in certdata. ***

*** If you want to trust the certificate, you can add it to your CA certificate store or use it stand-alone with the
curl command line tool: --cacert [file] ***

to add to CA certificate store:
openssl x509 -outform der -in cacert.pem -out cacert.crt

sudo cp cacer.crt file to /etc/pki/ca-trust/source/anchors -- this location for CentOS machine
* sudo cp cacert.crt /usr/local/share/ca-certificates -- this location for Ubuntu 16 *

sudo update-ca-trust extract (Centos8)
* sudo update-ca-certificates (others distro versions) *
* sudo dpkg-reconfigure ca-certificates (Ubuntu 16) *

Nagios xi License Policy
With every purchase we offer 3 separate activation of xi licenses. One for production, one for testing, and one for high availability. We always recommend upgrading on a test server first before making changes to the production server.

Nagios License Entitlements
https://support.nagios.com/kb/article.php?id=145