Fixing this issue involves making a tweak to your TCP listener's config stanza. For the TCP listener, Vault includes a parameter called tls_disable_client_certs which allows you to toggle this functionality. By default, the value of this parameter is false
and Vault will request client certificates when available.
To disable this behavior, simply update the TCP listener stanza in your Vault configuration file to include the following line.
tls_disable_client_certs = "true"
Below is an example of how this would look in a Vault configuration file.
...
listener "tcp" {
address = "0.0.0.0:8200"
tls_cert_file = "/opt/vault/tls/vault-cert.crt"
tls_key_file = "/opt/vault/tls/vault-key.key"
tls_client_ca_file = "/opt/vault/tls/vault-ca.crt"
tls_disable_client_certs = "true"
}
...
If you'd like to read more, I wrote a knowledge base article detailing how to handle this.