Avoid problems concerning proxy servers and firewalls when communicating between client & server applications

[Probotector]

Hi all,

Im developing an application consisting of a client part and a server part. There will be some communication (data transfer both ways) between these parts and I'm wondering what way to go (TCP/IP, .NET, Web Service etc.)? It is important to minimize the problems concerning situations when the client application is connected to the Internet via a corporate network where proxy servers and firewalls may be present. I would prefer not to use VPN tunnels.

I'll be very grateful if I get comments on this.

/Jon

[mikeporter]

With the information you gave it is really hard to say. What kind of data? How much? What are you reliability requirements? Who are the clients?

Mike...

[A.E.M]

Hi Jon.

Does that mean, that you cannot get help from your local IT Department to open ports, etc?

If you use TCP/IP all you normally need to do, is to open that port in your router and make sure the port is also allowed in your firewall. But if you cannot get help from your IT guys, then that might be a problem.

I can think of another solution: You can use a web service. You can use the one that is build into LabVIEW. However, when using a Web Service you would also need to create your own webpage that make the calls and translate the messages into something meaningful for your user.

Tutorial: Creating and Accessing a LabVIEW Web Service (Real-Time, Windows)

With newer versions of LabVIEW, we're using port 8080 for this. However, you can actually change that to port 80 which is the default port for HTML communication. I'll then assume that you will not run into network configuration problems.

Default Web Service Port Change

I hope this helps.

[Probotector]

The data sent from the client is a configuration file (about 10 KB of text) and the data returned from the server is a binary (about 1.5 MB). The communication must of course be reliable and important is that there is a smooth solution even for those who are behind proxies / firewalls (big companies).

[Probotector]

Hi Alex,

I have experience developing client-server concept, where the communication took place over TCP/IP. When the client was located behind corporate proxy servers the data communication was prevented and the local IT department needed to be contacted. In some cases it wasn't that easy to be granted to open the ports necessary and in these cases VPN tunnels have been used instead to get the client-server data traffic going.

I would prefer a smooth solution with no dependencies of contacting the local IT department for port opening.

[mikeporter]

I understand your concern, but it is unfortunately "their" wires, so you have to play by their rules. TCP/IP sounds like a good choice -- especially since everything else is based on TCP/IP anyway. Something that I have found to be helpful sometimes is to get the customer involved in dealing with their IT department.

Mike...