Need to pass cookies between machines on the same LAN?

Then in your web.config use an authentication section similar to the following:

<authentication mode="Forms">
    <forms 
           name="myCookie"
           timeout="20"
           loginUrl="Default.aspx"
           defaultUrl="Default.aspx"
           protection="All"
           path="/"
           requireSSL="false"
           slidingExpiration="true"
           cookieless="UseDeviceProfile"
           domain="domain.com"
           enableCrossAppRedirects="true"
    />
</authentication>

Internet Explorer will only pass cookies from one site to another if they have the domain cookie attribute set; i.e. the Fully Qualified Domain Name is required. Moreover all GET/POST must use the FQDN, as any Response.Redirect. The reason behing this is security, to make sure that a cookie is not passed to another site, thus exposing to cookies stealing.

Carlo