How to check if TCP/IP connection is active with a device

[sohaib_a]

Hey.. I really at my wits end on this. I have a device that i connect to through TCP/IP using an api function call. Because there could be cases where maybe the router/switch restarted or the network went down or something and if this happens then the device should connect automatically again. I need a to check the the connection status of the device,whether it is connected to application or not so then i can reconnect automatically. I did something like this

Dim information As TcpConnectionInformation
For Each information In IPGlobalProperties.GetIPGlobalProperties.GetActiveTcpConnections
If (information.RemoteEndPoint.Address.ToString = readerIp) Then
state = CInt(information.State)
End If
Next

However this updates the state only after i manually disconnect the device.It the i pull the cable out and plug it back in it still show the same state. Is there another way to this,to check where a connection is..(not like ping) but if there is an active connection between the device and pc.

[N a v a n e e t h]

AFAIK, ping[^] is the efficient way for this. Just ping the device and if you are getting acknowledgement, consider it as active. :)

Navaneeth How to use google | Ask smart questions

[sohaib_a]

i know but ping will only tell if the device is connected to the network..it will not tell me if there is an active connection(ie that there is some data flow between the device & pc). For instance the device is connected to my application(i can ping it as well)...however if i pull out the cable and plug it in back again..i can still ping it...but it isn't connected to my application anymore...so the ping check is not enough for this..it wont tell me if it is connected or not..is there some way to do this with sockets and ports?