DirectAccess and FIPS Compliant Algorithms for Encryption

DirectAccess administrators may be required to enable Federal Information Processing Standards (FIPS) compliant algorithms for encryption, hashing, and signing on DirectAccess servers to meet certain regulatory and compliance requirements.

DirectAccess and FIPS Compliant Algorithms for Encryption

Performance Impact

Be advised that enabling this setting will disable support for null cipher suites for the IP-HTTPS IPv6 transition technology. This will result in the double encryption of all DirectAccess client communication, which will increase resource consumption on DirectAccess servers. This leads to reduced scalability and degraded performance for all DirectAccess clients, including Windows 8.x and Windows 10.

If enabling FIPS compliant cannot be avoided, additional compute capacity (CPU and memory) should be provisioned. For best results, add additional servers to distribute the workload and improve performance for DirectAccess clients.

Always On VPN

If you’re looking for better security and performance, consider migrating to Windows 10 Always On VPN. Always On VPN fully supports FIPS compliant algorithms without the negative performance impact associated with DirectAccess. If you’d like to learn more about security and Always On VPN, fill out the form below and I’ll get in touch with you.

Additional Resources

Always On VPN and the Future of DirectAccess 

5 Things DirectAccess Administrators Should Know About Always On VPN 

3 Important Advantages of Always On VPN over DirectAccess 

SSL Certificate Considerations for DirectAccess IP-HTTPS

SSL Certificate Considerations for DirectAccess IP-HTTPSDirectAccess uses IPv6 exclusively for communication between the client and server. IPv6 transition technologies are used to support DirectAccess communication over the IPv4 public Internet. One of those IPv6 transition technologies, IP-HTTPS, uses HTTP for encapsulation and SSL/TLS for authentication of the DirectAccess server.

SSL Certificates

When configuring DirectAccess, an SSL certificate must be provided for IP-HTTPS. There are three different types of SSL certificates that can be used.

Public SSL Certificate – Using an SSL certificate signed by a public certification authority (CA) is the recommended best practice for configuring DirectAccess IP-HTTPS. This provides the highest level of assurance for DirectAccess clients connecting via IP-HTTPS.

Private SSL Certificate – Using an SSL certificate issued by the organization’s internal CA is an acceptable alternative to using a public SSL certificate in most cases. This can reduce the cost associated with obtaining the certificate, especially for multisite deployments.

Self-Signed Certificate – Using a self-signed certificate is not recommended and should be avoided in most deployment scenarios. A self-signed certificate provides no real assurance for DirectAccess clients. Crucially, using a self-signed certificate will disable support for null SSL and TLS cipher suites. This reduces the overall scalability and performance of the remote access solution.

SSL Certificate Considerations for DirectAccess IP-HTTPS

Figure 1. Null cipher suites not supported when using a self-signed SSL certificate for IP-HTTPS.

Certificate Requirements

The SSL certificate must include the Server Authentication (1.3.6.1.5.5.7.3.1) Enhanced Key Usage (EKU) Object Identifier (OID). It should use an RSA key of 2048 bits and be signed with SHA256. Using stronger keys provides no additional protection and should not be used. In addition, SSL certificates using ECDSA keys is not recommended, as they do not support null cipher suites.

Summary

In most cases, using a public SSL certificate is ideal. However, issuing a certificate from a private CA is also acceptable. Using self-signed certificates can be used for non-production testing and in very small production deployments, but should generally be avoided.

Additional Resources

DirectAccess IP-HTTPS SSL and TLS Insecure Cipher Suites

DirectAccess and Multi-SAN SSL Certificates for IP-HTTPS

Troubleshooting DirectAccess IP-HTTPS Error 0x80090326

A Windows 7 or Windows 8.x/10 client may fail to establish a DirectAccess connection using the IP-HTTPS IPv6 transition technology. When troubleshooting this issue, running ipconfig.exe shows that the media state for the tunnel adapter iphttpsinterface is Media disconnected.

Troubleshooting DirectAccess IP-HTTPS Error 0x80090326

Running the Get-NetIPHttpsState PowerShell command on Windows 8.x/10 clients or the netsh interface httpstunnel show interface command on Windows 7 clients returns and error code of 0x80090326, with an interface status Failed to connect to the IPHTTPS server; waiting to reconnect.

Troubleshooting DirectAccess IP-HTTPS Error 0x80090326

Error code 0x80090326 translates to SEC_E_ILLEGAL_MESSAGE, indicating the client encountered a fatal error during the SSL handshake.

Troubleshooting DirectAccess IP-HTTPS Error 0x80090326

There are a number of things that can cause this to happen. The most common scenario occurs when an Application Delivery Controller (ADC) is improperly configured to perform client certificate authentication for IP-HTTPS connections. Common examples are an incorrect or missing root CA certificate, or null SSL/TLS cipher suites not enabled when supporting Windows 8.x/10 clients.

To troubleshoot DirectAccess IP-HTTPS error 0x80090326, perform a network trace on the DirectAccess client and observe the TLS handshake for clues as to which configuration error is the culprit. If the TLS handshake failure occurs immediately after the client sends a Client Hello, it is likely that the ADC does not have null cipher suites enabled.

Troubleshooting DirectAccess IP-HTTPS Error 0x80090326

If the TLS handshake failure occurs after the Server Hello, it is likely that the ADC is configured to perform client certificate authentication incorrectly, or the client does not have a valid certificate.

Troubleshooting DirectAccess IP-HTTPS Error 0x80090326

IP-HTTPS error 0x80090326 can also occur if an intermediary device is performing SSL/TLS inspection or otherwise tampering with the TLS request. It can also happen if the edge firewall and/or NAT device is forwarding IP-HTTPS connections to the wrong internal server, or if the firewall itself is responding to the HTTPS connection request. Remember, just because the server is responding on TCP port 443 doesn’t necessarily mean that it is the DirectAccess server responding!

Additional Information

Troubleshooting DirectAccess IP-HTTPS Error Code 0x90320

Troubleshooting DirectAccess IP-HTTPS Error 0x2af9

SSL Certificate Considerations for DirectAccess IP-HTTPS

DirectAccess Troubleshooting Consulting Services

Implementing DirectAccess with Windows Server 2016