CODEWITHSUNDEEP
javanetwork-programmingip
Charlie Brown
Charlie Brown

Reputation: 183

How do I distinguish if two IPs belong to the same computer?

We have a master program and agents (both) on the customer side on different computers. The network configuration can be any type (we don't know). The agents connect to the master program and currently we only can get the IP and computer name as information. How do I distinguish if two IPs belong to the same computer?

Computers may have more than one ethernet cards.

Thanks.

Upvotes: 4

Views: 1168

Answers (4)

jefflunt
jefflunt

Reputation: 33954

You say you're getting the computer name - can't you de-duplicate based on that value?

From across a network, and given only an IP address, you can't tell. The way NAT works, and the fact that today's laptops and wireless devices often hop from network to network throughout the day, all you see is the public-facing IP address of that machine, which is very likely shared across a group, or entire organization of machines.

Unless you modify the agent application to also include a unique identifier (such as MAC address - which even then only tells you it's a unique NIC, not necessarily a unique machine if machines have multiple NICs), you're out of luck. You can't determine uniqueness from the IP address alone.

Not sure what your use case is, but if it's for banning/tracing actions within the application, then it's better to require some kind of unique identifier for the machine to access the system (such as a username) so you know that you can ban/trace a single instance of the app, or a single user logged into any instance of the app, rather than trying to solve that kind of a problem through IP addresses.

Upvotes: 1

sarumont
sarumont

Reputation: 1762

You can modify the agents to send the MAC(s) of the machines in question. Beyond that, you can't really determine if they are the same.

Upvotes: 1

kgiannakakis
kgiannakakis

Reputation: 104198

You could create a service in its machine that will expose a unique identifier. You could then call this service using different IPs as the host name and compare the values.

Upvotes: 0

Erick Robertson
Erick Robertson

Reputation: 33082

There is no way to tell just by looking at the IP addresses.

Some computers have unique identifiers, but you would need JNI to access them and your code would be very platform-specific. It might be a better idea to generate a GUID and write it to a file in a temp folder on the machine. Then, all instances of the software that run on that machine would read the same GUID and can provide this data to the server when a connection is made.

Upvotes: 5

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