How can you implement logout functionality in Forms Authentication?

Question

ICSM Computer · Answer

To implement logout functionality in Forms Authentication, you use the
FormsAuthentication.SignOut() method. This removes the authentication ticket (cookie) and effectively logs the user out.
Steps to Implement Logout
ASP.NET MVC Controller Action
public ActionResult Logout()
{
    FormsAuthentication.SignOut();  // Remove auth cookie
    Session.Abandon();              // Optional: clear session data
    // Redirect to login or home page
    return RedirectToAction("Login", "Account");
}
ASP.NET Web Forms Code-Behind
protected void LogoutButton_Click(object sender, EventArgs e)
{
    FormsAuthentication.SignOut();  // Remove auth cookie
    Session.Abandon();              // Optional: clear session
    Response.Redirect("~/Login.aspx");
}
Optional Cleanup
Session.Abandon(): Clears all session variables and releases the session ID.FormsAuthentication.SignOut():Invalidates the authentication cookie.Does not end the session unless you call Session.Abandon().
Optional: Redirect to the FormsAuthentication.LoginUrl
return Redirect(FormsAuthentication.LoginUrl);
Security Best Practices
Always call FormsAuthentication.SignOut() before abandoning session.Clear any persistent cookies or cached identity info if manually created.Consider setting the auth cookie's expiration in the past manually, though 
SignOut() typically handles this.
if (Request.Cookies[FormsAuthentication.FormsCookieName] != null)
{
    var cookie = new HttpCookie(FormsAuthentication.FormsCookieName, "")
    {
        Expires = DateTime.Now.AddYears(-1)
    };
    Response.Cookies.Add(cookie);
}

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How can you implement logout functionality in Forms Authentication?

ICSM Computer

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1 Answers

Steps to Implement Logout

ASP.NET MVC Controller Action

ASP.NET Web Forms Code-Behind

Optional Cleanup

Optional: Redirect to the `FormsAuthentication.LoginUrl`

Security Best Practices

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