We generate certificates that are intended to be used for server authentication in a couple of places:

- `bin/elasticsearch-certutil http` command  ( See `CertGenUtils.generateSignedCertificate` in `HttpCertificateCommand` )
- TLS auto-configuraion for node startup ( see [`AutoConfigureNode`](https://github.com/elastic/elasticsearch/blob/814f7f9f52cb8c05db6465b9bfc818ea5d76c575/x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/AutoConfigureNode.java#L454) )

In these cases we know that the certificate is meant to be used for server authentication, so we can set Extended Key Usage extension to `1.3.6.1.5.5.7.3.1`
x-pack/plugin/security/cli/src/main/java/org/elasticsearch/xpack/security/cli/AutoConfigureNode.java
final String cnValue = NODE_NAME_SETTING.exists(env.settings()) ? NODE_NAME_SETTING.get(env.settings()) : System.getenv("HOSTNAME");
        final X500Principal certificatePrincipal = new X500Principal("CN=" + cnValue);
        final X500Principal caPrincipal = new X500Principal(AUTO_CONFIG_ALT_DN);
        if (inEnrollmentMode) {
            
            final EnrollmentToken enrollmentToken;
            try {
                enrollmentToken = EnrollmentToken.decodeFromString(enrollmentTokenParam.value(options));
            } catch (Exception e) {
                try {
                    deleteDirectory(tempGeneratedTlsCertsDir);
                } catch (Exception ex) {
                    e.addSuppressed(ex);
                }
                terminal.errorPrintln(Terminal.Verbosity.VERBOSE, "");
                terminal.errorPrintln(
                    Terminal.Verbosity.VERBOSE,
                    "Failed to parse enrollment token : " + enrollmentTokenParam.value(options) + " . Error was: " + e.getMessage()
                );
                terminal.errorPrintln(Terminal.Verbosity.VERBOSE, "");
                terminal.errorPrintln(Terminal.Verbosity.VERBOSE, ExceptionsHelper.stackTrace(e));
                terminal.errorPrintln(Terminal.Verbosity.VERBOSE, "");
                throw new UserException(ExitCodes.DATA_ERROR, "Aborting auto configuration. Invalid enrollment token", e);
            }
            final CommandLineHttpClient client = clientFunction.apply(env, enrollmentToken.getFingerprint());
            
            
            HttpResponse enrollResponse = null;
            URL enrollNodeUrl = null;
            for (String address : enrollmentToken.getBoundAddress()) {