If a laptop is connected both via WiFi and Ethernet to the same network, can the two network cards share the same IP address?

That way, requests for that computer can go to one IP only, and, in case any of the two connections are disconnected, no connection is interrupted.

What I'm imagining is this:

On a subnet, if the WiFi would have IP address x.x.x.101 and the Ethernet would have IP address x.x.x.102, someone connecting to the computer via .101 would be disconnected if the WiFi is interrupted, and someone connecting to the computer via .102 would be disconnected if the Ethernet cable is unplugged. If both network cards would have the same IP, as long as at least one of them is connected to the network at a time, all connections would stay up.

I have close to no experience with networking. I imagine such a thing would likely exist, but I'm not sure how easy it would be to do it or if it would be worth it.

  • On the same network, the wireless connection will have a different IP address from the wired connection. It is generally not a good idea to have both connected and you may need third party software to make it work. – John Oct 18 '20 at 19:30
  • No, you can't use the two interfaces together for more bandwidth. This has been asked often enough. – harrymc Oct 18 '20 at 19:31
  • With Linux the IP address is assigned to an interface, but is effectively owned by the host. So any active interface of the host could respond to the IP address, which is known as the arp flux problem. See netbeez.net/blog/… So a Linux host might still respond to the IP address of an unconnected interface. – sawdust Oct 19 '20 at 3:56
  • This is possible - but not necessarily desirable in Linux if you channel bond the 2 interfaces. – davidgo Oct 19 '20 at 9:24
  • Hi, (1)“the wireless connection remains active when a wired connection is made” can be achieved by changing the network card priority. (2) However, configuration the two NICs have the same IP address may not be achieved. – Gloria Gu Oct 20 '20 at 7:08

No, the same IPs on two different network interfaces on one network will cause an IP conflict and connections will sometimes work and sometimes not, depending on the capability of the devices being able to detect and avoid those conflicts.

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