We have an existing single sign on (SSO) implementation where we redirect users using My Domain to an ADFS server through a mediation layer. In short, the SSO dance looks like this:
* These servers are internal to our network, sit behind our firewall, and exist only in our DNS.
This works well on our desktops browsers (best on Internet Explorer, of course), but we've also set up a VPN connection that works with mobile devices. In this case, we connect through the VPN service using a secure token, then we try to authenticate with Salesforce1 by entering our custom My Domain.
We've had several obstacles around this, including the need to place a publicly trusted SSL certificate onto the private internal server, but our latest attempt is the most baffling of all.
Our network guru can see the client connecting to the ADFS (Active Directory Federated Services) server, but it never progresses beyond that. On the client itself (e.g. iPad), we get a spinning circle icon that never goes away. The request never times out, displays an error message, etc. In short, we have no idea why it's not working.
This same SSO dance works on our mobile browser, such as Safari, although it does make us authenticate with ADFS first using our username/password from Active Directory. This is an acceptable flow, since we plan on letting devices stay authorized indefinitely (needing only a mobile pin).
Is there some special configuration we need to have to make ADFS work with the Salesforce1 mobile app with SSO? Are there certain restrictions on what type of servers can be used with the SAML flow? Nothing in the documentation suggests that there are limitations of this nature, so I thought I'd ask the community to see if anyone has successfully implemented ADFS SSO and what special considerations were required to make it work through a VPN.