RE: DPD & DPV requirements

[Stephen Kent <kent@xxxxxxx>]

Skip,

If we do agree to support DPV server recursion, then the suggested 
changes are appropriate ones to consider.

First, though, on what basis would you propose that a client 
enable/disable recursion or set a depth limit? Since a client is 
completely dependent on a DPV server to answer a query, and has no 
local means of validating any supporting data sent along with the 
answer, what does recursion say about the trust that the client 
places in the server? If one believes that trust is transitive, 
recursion may well be fine, and a simple numerical limit on depth of 
recursion would not seem to be a good way to express limits on the 
transitivity (e.g., one bad choice of a DPV server for reliance is 
enough to kill you). If you don't think trust is transitive, then 
recursion is inappropriate, unless you operate in a closed 
environment where the recursion is among servers operated by the same 
org and is really just an internal decision on how to implement the 
server.

Perhaps this is one reason why I am not yet comfortable with adding 
recursion to servers. I'd like to see some analysis of why it makes 
sense, whether it makes sense for both DPD and DPV, etc.

Steve