I've configured forwarders to use SSL certificates that are checked against the rootCA defined on the indexers.
I am wondering if the indexers will reject the certificates once we are past the expiration date of the forwarders certificates.
I am asking because those certificates are going to be setup on machines that are at our customers and, most likely, they won't be renewed afterwards.
So I need to know if Splunk indexers only checks that the certificates have been signed by the rootCA or if it also does complementary checks like the validity of the certificates.
Others will probably know better, but I believe the forwarders do not check certificates at all. They are provided as part of the connection process. If the certificates are expired, connections will simply fail.
The answer is the same - none. Certs are merely handed to the OS to use to authenticate a connection. If the cert is expired the connection fails. One would hope an error is logged, but there is no "dude, you know this isn't going to work, right?"