#QT GET MAC ADDRESS FROM IP MAC#

Routers and switches also have facilities for preventing such things. Many operating systems therefore allow settings to lock ARP cache entries, to prevent J and K stealing the mail of their neighbours A and B. The usual reason for this kind of frame with incorrect ether source address is an intended ARP cache poisoning attack, and very occasionally innocent misconfiguration of something. You'll see that in the local and remote cases, the thing that goes wrong is that an ARP cache is updated with incorrect information, and switches' CAM tables. I've described the ordinary situation with common operating systems, switches, and routers these are designed to minimise the management required, at the cost of being open to certain kinds of problem. Just like the local case, depending on the details of the switch, K could be the destination, or able to snoop the frame. R receives the packet, see it's for a local network, and wraps in ether with the poisoned ether address from its cache.

#QT GET MAC ADDRESS FROM IP MAC#

For obtaining the MAC address of a remote IP you should use system commands and platform-specific code. Call addresses () to get the list of IP addresses for the host, and hostName () to get the host name that was looked up. X receives and formulates reply, which will be directed to R because B is not local. The results are stored in a QHostInfo object. More likely it updates its ARP cache for B, and forwards the packet to X. What happens next depends on the upper protocol, whether A notices it hasn't had a reply and starts resending, etc.ī sends packet to X with correct IP source address but incorrect source MAC addressī sends frame through the switch, which updates its CAM table, to R, which might conceivably reject it. If no host actually has that ether address, J might still be able to snoop the frame, depending on the details of the switches. The switch will normally send the reply towards the original sender, but potentially if the incorrect ethernet address is that of another host J, that host will receive the frame and do whatever it likes with it. Reply to A's IP address will get wrapped in the wrong ether address for the poisoned ARP cache. Result: frame arrives at switch, which updates its CAM table, then frame arrives at X, which updates its ARP table, hands UDP packet upstairs in its stack, which generates a reply.

B KĪ sends packet to X with correct IP source address but incorrect source MAC address Consider the following network, with correct addressing, masks and the obvious routes.

Qt get mac address from ip