We have an established Intranet based on WSS with two front ends and a database.
Currently all authentication is NTLM.
We have installed Reporting Services In Integration Mode.
RS works as long as the web front end that has RS installed on it handles the transactions.
If the front end without RS handles the request then we get an UNAUTHORIZED error.
In attempting to fix this problem, web searches etc. - have alluded to the problem being caused by the farm needing to perfrom 'double-hop' authentication - which cannot happen via NTLM.
So we need to configure the Intranet farm to accept Kerberos authentication.
I've found this helpful guide But it takes the stance that we are starting the farm from scratch.
So we need to know whether there are any risks involved in retroactively configuring Kerberos? Will NTLM carry on as before while and after we have carried out the steps to enable Kerberos?