An SSL certificate is required to support the IP-HTTPS IPv6 transition technology when configuring DirectAccess. Implementation best practices dictate using a public SSL certificate signed by a trusted third-party vendor such as Entrust, Verisign, DigiCert, and others. SSL certificates issued by a private PKI are acceptable if the client trusts the issuing CA. Self-signed certificates are supported in some deployment scenarios, but their use is generally discouraged. For more detailed information regarding SSL certificate considerations for DirectAccess IP-HTTPS click here.
Symantec Issued Certificates
Symantec is a popular commercial SSL certificate provider that has been commonly used for many years. However, due to integrity issues associated with their PKI management practices, Google and Mozilla announced they will soon be deprecating these certificates. This means users who browse to an HTTPS web site protected with a Symantec SSL certificate will receive a warning in their browser indicating the certificate is not trusted.
DirectAccess IP-HTTPS
It is important to note that there is no impact at all for DirectAccess when the server is configured to use an SSL certificate issued by Symantec. There is nothing you need to do to address this issue in this scenario. However, if a wildcard certificate is installed on the DirectAccess server and it is also used on other public-facing web servers in the organization, it is likely that the certificate will replaced, perhaps by another certificate provider. In this case, DirectAccess IP-HTTPS must be configured to use the new or updated SSL certificate.
Updating IP-HTTPS SSL Certificate
To update the DirectAccess IP-HTTPS SSL certificate, import the SSL certificate along with the private key in to the local computer certificate store on each DirectAccess server. Next identify the thumbprint of the new SSL certificate. Finally, open an elevated PowerShell command window and enter the following command.
$thumbprint = “ssl_cert_thumbprint”
$cert = Get-ChildItem -Path cert:\localmachine\my | where {$_.thumbprint -eq $thumbprint}
Set-RemoteAccess -SslCertificate $cert -PassThru
Be sure to replace “ssl_cert_thumbprint” with the actual thumbprint of your SSL certificate. 😉 In addition, for load-balanced and/or multisite deployments, run these PowerShell commands on each server in the enterprise.
Additional Information
SSL Certificate Considerations for DirectAccess IP-HTTPS
The Name Resolution Policy Table (NRPT) in Windows provides policy-based name resolution request routing for DNS queries. DirectAccess uses the NRPT to ensure that only requests for resources in the internal namespace, as defined by the DirectAccess administrator, are sent over the DirectAccess connection. DNS queries for all other namespaces are sent to the DNS servers defined on the client’s network interface.
DirectAccess connections are bidirectional, allowing administrators to remotely connect to clients and manage them when they are out of the office. DirectAccess clients use IPv6 exclusively, so any communication initiated from the internal network to remote DirectAccess clients must also use IPv6. If IPv6 is not deployed natively on the internal network, the Intrasite Automatic Tunnel Addressing Protocol (ISATAP) IPv6 transition technology can be used to enable manage out.
