Ever tried to get FTP protocol through FW/NAT?
It requires protocol level command channel tracking, to find out related
data channels and let them in.
Special handling, special modules, special setup - ergo: nobody bothers.
Well as has been already pointed out by Dave what you are talking about
(PORT FTP) is completely different from what I suggested in that its the
client opening the port and not the server, what I was suggesting was
the server having an extra port open (or even the normal XMPP C2S port
with a special negotiation turning it into a framed binary connection)
and just maintaining two connections to the server, one that carries the
normal XMPP traffic and one that carries the binary frames, you could
even just use a single framed binary connection (rather than two) and
have a special XMPP XML frame type to denote it containing XMPP stanzas,
this is what I do in my server implementation which supports framed as
well as normal XMPP streams, among other things I find it makes
implementing a low overhead keepalive/pingpong protocol a whole lot easier.
This is one of the reasons why HTTP (one connection) is omnipresent,
even for file archives, and FTP is becoming forgotten.
Sorry but that is not the actual reason by any means, and there are
plenty of FTP archived around, have you never downloaded a linux ISO?
Most of the linux ISO download servers i've come across have been FTP
servers, but anyway this is getting rather off topic.
Richard
