Check if Firewall exists?

[dotnetman]

Friends,
Is there any way I can check if a certain computer (connecting to a network) is getting blocked by a firewall. I have remoted my project and am trying to run my UI App on one machine and a remote business server on another. Now, I have also implemented a Web service that provides the same function but is for clients outside of our network. I would like to have a check where I could identify if there is a firewall. If so, switch my application to connect to the Web service rather than the remote server.

I dont know if Im making sense here, but itd be good to know if we could have a utility that checks for firewall presence.

Thanks,
DTM

 

[Mister E]

Theres no way to "probe" a network from over the Internet to see if its utilizing a firewall.

If youre running a remoting server on a machine thats on a LAN (which is connected to the Internet) and youre not able to connect to it over the Internet then it is likely that the port the remoting server is using is not mapped to the internal IP of the system it is running on.

.NET Remoting runs over TCP or HTTP (which runs on TCP). TCP requires a IP/port endpoint to connect to. Since the remoting client is sending an unsolicited TCP connection request it will be killed by the piece of hardware (router) where the NAT is taking place.

You need to get a port mapped to your internal IP. If you dont have access to this, then you will not be able to initiate remoting sessions from over the Internet. Using the Web Service route would be your best bet. You could try to connect to the remoting server first and, if that fails after a certain period of time, switch over to the Web Service.

 

[dotnetman]

Thanx Mister E. I will probably have to go with the route you suggested. Hell Web Services are so slooooow mann But you gotto do what you gotto do