CODEWITHSUNDEEP
c#network-programmingdevice
Benjol
Benjol

Reputation: 66607

Detecting when a device has changed physical ethernet port

My code is running on a server with multiple Ethernet ports which are physically wired to specific physical locations. Devices with known IPs are plugged in the other ends. I want to be able to detect if a device has changed place (in order to warn/scold the user). I.e, the difference between this:

Port X (192.168.33.1) ------------------ Device A (192.168.33.12)
Port Y (192.168.33.2) ------------------ Device B (192.168.33.13)

and this:

Port X (192.168.33.1) ------------------ Device B (192.168.33.13)
Port Y (192.168.33.2) ------------------ Device A (192.168.33.12)

I've considered putting the devices/ports on different subnets, but I would prefer to be able to say "you need to move device C to position N", rather than "I can't see anything!".

Disclaimer: I am not a networking expert

Upvotes: 0

Views: 107

Answers (1)

Damien_The_Unbeliever
Damien_The_Unbeliever

Reputation: 239804

Presumably, you're actually talking to these devices in some way, shape or form, and sooner or later you'll have a Socket object (either one you directly created or one that you can obtain from a higher level object such as TcpClient's Client property.

Once you've actually used the socket, you'll be able to query the LocalEndPoint property and determine which local IP address you actually used to talk to the remote system:

The LocalEndPoint property is usually set after you make a call to the Bind method. If you allow the system to assign your socket's local IP address and port number, the LocalEndPoint property will be set after the first I/O operation. For connection-oriented protocols, the first I/O operation would be a call to the Connect or Accept method. For connectionless protocols, the first I/O operation would be any of the send or receive calls.

Upvotes: 1

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