[pca] Heads-up: New download service

[Martin Paul]

Don O'Malley wrote:
> There is load balancing performed on the backend to share the load between 
> limelight and Akamai.
> To cover all scenario's the following should be added to your firewall:

A really long list. Lucky me that I don't have to deal with rules for outgoing 
connections on our firewall. I've updated the list in the PCA installation 
instructions, too:

   http://www.par.univie.ac.at/solaris/pca/installation.html

Martin.