RE: what http/https/ftp/smts proxy/relay to use on a network firewall
>>What exactly is a "layer 3 proxy for server publications" supposed to
I Would say this is how Microsoft ISA Works. You decide what resources you publish.
>>> http proxy should be able to:
>>> termination https connections (use http to internal servers)
>>Why would you want to break https?
To Decrease the load on the back end server. This is a feature of ISA. ISA is able to handle the SSL part and terminate it.
>>> handle (s)ftp (maybe a separate component)
>>Why would you want to break ssh?
Who is talking of ssh ?