[sldev] agent-domain branch

[Soft]

On Mon, Mar 3, 2008 at 5:10 PM, Fairlight <fairlight at tigress.com> wrote:
> Hi!
>
>  Hmm.. does "The Agent Host establishes a connection with the client" mean
>  that the server at LL will start a tcp connection with the user client?
>
>  I am asking because that could cause all kinds of problems with clients
>  behind NAT and Firewalls, where the internal IP of the client does not
>  match the IP the connection seems to come from and where a connection to
>  the external IP would require special router rules to be forwarded to the
>  internal network. In addition, if you have more than 1 client behind the
>  NAT/Firewall, this will fail, if  static. And if it is not static, you
>  need a matchign dynamic filter for the Firewall..
>
>  All in all, I hope the servers never initiate a connection to the client!

The long poll technique is used here. The client opens a connection
with the server, which the server responds to when it would have
wanted to initiate a connection itself. On receiving a response, the
client opens another request. AJAX apps have been using this for
years.