There was another gotcha.
All the ports we needed for this arcane application were opened late yesterday lunchtime, so we could open a TCP socket from a PC on client X's subnet here in Paris to the AS400 on client P's subnet in London via client X's London network.
The application doesn't attempt to open the socket, and the person I need to talk to in client P's London office is out until Friday. He wrote the application. We suspect that we have a missing DLL, or that the ODBC connection isn't right or something, but he's the one who can tell us how to fix it, and he's not about.
We decided that we can sort that out later.
I was within half an hour of leaving yesterday afternoon when it emerged that printing from some AS400s on the same subnet (different application) wasn't playing. After a good deal of playing around on the firewalls/routers/open ports front, the data stream was being delivered to the correct printer successfully. However, the printout is unreadable.
It transpires that client P has changed things at their end so they're now sending PCL fonts instead of bitmapped fonts. There was a lot of running around trying to establish that it was something we'd done (no, once the socket is open the data stream gets delivered intact) but now we know what's going on.
I can't leave until we have a successful cheque print run done.
This morning, the connection to client P's London AS400s is down, somewhere the far side of client X's London firewall.
See you all later.