strongSwan

h1. Requirements for certificates used with Windows 7

The Windows 7 Beta release was liberal in accepting certificates, but the Release Candidate adds new requirements for the VPN gateway certificate.

h2. Required fields

Your gateway certificate must have:

* An *Extended Key Usage* flag flag, explicitly allowing the certificate to be used for authentication purposes. It is currently unclear which OIDs are accepted by Windows, but it seems that the *serverAuth* EKU having the OID _1.3.6.1.5.5.7.3.1_ (often (_1.3.6.1.5.5.7.3.1_, often called _TLS Web server authentication_) is ok. gets accepted. If you are using OpenSSL to generate your
certificates then include the option

<pre>
extendedKeyUsage = serverAuth
</pre>

* The hostname of the VPN gateway entered in the clients connection properties *MUST* be contained either in the *subjectDistinguishedName* of the server certificate

<pre>
C=CH, O=strongSwan Project, CN=vpn.strongswan.org
</pre>

or in a *subjectAltName* extension that can be added with the option

<pre>
subjectAltName = DNS:vpn.strongswan.org
</pre>

h2. Disabling extended certificate checks

Alternatively, you may disable these extended certificate checks on the client.

> *This is potentially dangerous, as any certificate holder assured by your CA may act as the VPN gateway.*

To disable the extended checks, add a _DWORD_ called *DisableIKENameEkuCheck* to

<pre>
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\RasMan\Parameters\
</pre>

in the client's registry.

h2. Further information

For more details about the requirements and other ways to disable the certificate checks, have a look to "this knowledge base article":http://support.microsoft.com/kb/926182.