It is a longer tale, so to make keep it short I decided to busy the lead and give you the synopsis right here:
If you are running IBM Connections integrated with Exchange as your ICMail setup you are using Kerberos. If you want to enable external collaboration by adding another LDAP source for your external users – it will not work.
You can create the repository, add it to WebSphere, you can do all the TDI settings to import the users in it as external users .. but they will not be able to authenticate. The reason is that WebSphere has the authentication mechanism at it’s top level of security (global) and not at the repository level. That means, once you use Kerberos you have to use Kerberos for ALL authentication that happens. Trust me, I have tested. I had PMRs open (with both Connections and WebSphere support). I talked to the IBM Connections Product team and verified that this specific scenario was never actually tested so nobody appears to have known of this, which is also why it never made it’s way into any documentation.
I don’t think there are many clients for whom this might be an issue currently, but I do see many environments wanting more security and wanting to tie in other back-end systems and if that client environment is running AD as their LDAP source , then KERBEROS will be right there as a feature request – or a necessity.
Is External Collaboration Dead when Using Kerberos?
That is an easy answer – No.
But you are now forced to add those external users to your AD forest and either add them to some branch/OU that you can treat as external users or add some AD/LDAP attribute to identify them as external users.
Feature Enhancement Request for WebSphere – PLEASE VOTE!
I entered a feature enhancement request to move the authentication method from a global setting to the repository level – either in general or as art of a security domain setup in WebSphere, thereby allowing non-Kerberos repositories to be used for authentication alongside a KERBEROS enabled repository.
Here is the link to the feature request – the more people look at it, follow it and vote for it the more likely it is to make it’s wat into a future release. you will need to have an IBM website ID to even just look at it but I’d appreciate the effort!