🚀 go-pugleaf

OK, if no one knows what's going on here and why I keep losing the UDP
access, is there at least some way of re-setting a UDP port.  I'd settle
for a way to recover from the problem even if I can't understand or
prevent it.


I wrote:
> I have a server application that listens for customer queries coming
in
> over IP (both TCP and UDP), checks databases, and then sends back
> an answer.  Occasionally there are times (like when it loses
connectivity
> to a remote database, or when doing admin/maintenance on a local
> database) when the application needs to temporarily close those server
> ports in order to force clients over to an alternate site running
> another instance of the application.  Then when the situation is back
to
> normal, it needs to re-open the server ports.
>
> This works fine for TCP (using a TServerSocket component and its
> Close and Open methods), but now we're adding UDP access to the
> application, and I've found that once the UDP socket is closed, the
> application can't re-start it.  I'm using a TIdUDPServer component
> (from the Indy components that came with Builder 6).  I've tried
setting
> its Active property false and then true again.  Setting it false works
and
> we stop receiving the incoming UDP packets, but then when we set it
> back to true we should start seeing the incoming packets again but
> never do. (Setting Active to true is in a try-catch block, but no
exception
> is raised.)  The only way we've found to recover the UDP server socket
> is to manually shut down the whole application and then re-start it,
which
> is not a viable solution.
>
> I've now tried a partial solution where instead of disabling and then
> re-enabling the component, I simply set a global variable that tells
the
> application to temporarily ignore incoming UDP messages and not
> respond to them.  This works fine for instances where the application
has
> explicitly shut down UDP access, but we've now found that there are
> some instances (usually when we have a lot of traffic and the PC gets
busy
> for a while) that we seem to lose the UDP port even without having
> explicitly told it to stop listening.  These instances are more
> problematic.  We've already established that the application doesn't
> seem to be able to re-set the UDP port, so how can I make it recover
> from these cases when it stops receiving the UDP packets which are
> being sent to it?  (And what's really happening here anyway?  Why
> does the UDP port seem to just go away like that?)
>
> Lesley Anne