By default, vSphere uses TLS/SSL certificates that are signed by VMCA (VMware Certificate Authority). These certificates are not trusted by end-user devices or browsers.

As a security best practice, replace at least all user-facing certificates with certificates that are signed by a third-party or enterprise Certificate Authority (CA). Certificates for machine-to-machine communication can remain VMCA-signed.

Table 1. Design Decisions on the TLS Certificates of vCenter Server

Decision ID

Design Decision

Design Justification

Design Implication


Replace the vCenter Server machine certificate with a certificate signed by a third-party Public Key Infrastructure.

Infrastructure administrators connect to vCenter Server using a Web browser to perform configuration, management and troubleshooting activities. Using the default certificate results in certificate warning messages.

Replacing and managing certificates is an operational overhead.


Use a SHA-2 or higher algorithm when signing certificates.

The SHA-1 algorithm is considered less secure and has been deprecated.

Not all certificate authorities support SHA-2.