A read-only status string reporting the health of the Contivity's Certificate Revocation List (CRL) server used to check whether client or peer certificates have been revoked. If this drops to Alert or Warning, certificate-based VPN authentication may accept revoked certificates or fail authentication entirely, which is a security-relevant condition for a network admin to catch quickly. A security-conscious admin seeing crlServer report "Alert" would investigate whether the CRL distribution point is unreachable, since that could let a revoked client certificate still pass authentication.