Custom Windows Authentication Login Form

Question

When a user on a non-company asset (i.e. not connected to the domain) logs on to our SharePoint site, they are presented with a default windows popup dialog. We would like to remove this dialog and provide a log in form on our top-level site (which is set for anonymous access).

Is it possible to log a user in programmatically under Windows Authentication? How would I do this?

Note: The site MUST be set for Windows Authentication, so Forms Authentication with the ActiveDirectoryMembershipProvider won't work.

---

A little more context: The users will be connected to the internal network, but using their own computers (like students that connect to a school network), so VPNs are unnecessary. We are using MOSS 2007.

Answer 1

The Microsoft Threat Management Gateway 2010 can do this. See answers to this related question.

Answer 2

very do-able and not very difficult :-)

Read here: http://mikevallotton.wordpress.com/2010/10/18/sharepoint-2010-claims-authentication-custom-login-form-part-3-developing-a-custom-login-form/

The following two lines of code should do the job:

SecurityToken tk = SPSecurityContext.SecurityTokenForFormsAuthentication(
new Uri(SPContext.Current.Web.Url), "ADProvider", null,Username.Text, Password.Text);

if (tk != null)
    {
        SPFederationAuthenticationModule fam = SPFederationAuthenticationModule.Current;
        fam.SetPrincipalAndWriteSessionToken(tk);
    }