I have a wpf app that needs to communicate(exchange data) with a custom designed device (we can modify the code for the device). Do I have any options to connect to the device if it is behind a firewall via http? I was hoping there would be a method where the admin would not have to forward any specific ports or do anything on his end. I assume the issue is how would I address the device from my app. I know SOAP over SMTP is one option. Is another option where the device could chatter out to my application via http?
A:
A lot of firewalls are setup to allow access on port 80 (HTTP) otherwise the users wouldn't be able to browse web sites on the internet. You can try and see if port 80 is open to traffic. If you can modify the code for both the device and the client you can use port 80 to communicate with your own protocol - you don't necessarily need to use HTTP.
TLiebe
2010-03-27 16:16:22
How would I address the device?
tim
2010-03-27 20:57:43
I'm assuming the device has an IP address assigned to it. If it's a non-routable IP address (something like 192.168.xxx.xxx) then you'll have problems. If that's the case then you'll probably have to try one of the other methods suggested or get your firewall administrator to open another port and use something like port-forwarding. Posting your question on serverfault.com might get you some more ideas to try.
TLiebe
2010-03-28 01:43:08
A:
UPNP is supported by some firewalls to simplify this. Otherwise you are usually stuck opening ports on the firewall manually or using some 3rd party proxy server for a rendezvous server.
GregS
2010-03-27 16:23:14
Thanks I will research UPNP. The rendezvous server had occurred to me. Is there a way where if the device is powered up it could obtain and display some address information and then that could be used by the outside PC (say if the user called and said yeah the params on the display are...) to address the via device http or other.
tim
2010-03-27 18:18:46