Good point, didn't notice they included the private key in the certificate.pem file. Technically there is no need for the client to have the private key of the server certificate. This is against the whole concept of such private/public key cryptography. So it seems to me that those instructions are mistaken. It is also strange that they suggest to copy myServerCertificate.pem and the CA public certificate myCAPublicCertificate.pem, while myServerCertificate.pem already includes myCAPublicCertificate.pem. So I think the instructions in step 3 should read: copy the server public certificate myServerPublicCertificate.pem and the CA public certificate myCAPublicCertificate.pem into $SPLUNK_HOME/etc/certs/ on the forwarders.
Also, this line from step one clearly shows that the person writing that text has no proper understanding of how public/private key crypto works:
" This key will be used to encrypt the outgoing data on any Splunk instance where you install it as part of the server certificate. "
The client uses the server's public key to encrypt, upon which the server uses its private key to decrypt. Not the other way around.
I guess this warning at the top of the page (if you're logged in) is there for a reason: "Much of the content on this site is quite old, should be consumed with caution, and may be removed in the near future."
With "everywhere" I meant using the same key on server and client. As long as you use a different key on the server and only the client key is compromised, that only allows impersonation, it doesn't break confidentiality of the communication between other forwarders and the indexer.
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