how to smartly react on firewall denials?

"Richey / Delphi- & PHP-Box" <> wrote in message

> if the user denies access to the Internet using a software firewall
> like ZoneAlarm or ATGuard, how can I smartly "recover" Indy with an
> error message instead of letting strange stuff (for the end user) like

> "Socket Error # 10022 : Invalid argument" show up ?

I fail to see how you can tell the difference between
 - a fault on one of the hops between your app and its target
 - a blocking firewall on the server end
 - a blocking firewall on the client end

I guess you could try a traceroute and see how many hops you'll be able to
traverse, but that's not really a solution because you don't know which
packets the firewall(s) (if any) chooses to block. (i.e. the packets of your
app might reach the server, whereas it looks to you that the traceroute only
reaches the first firewall)