Get MAC address from IP of local network machine

usamytch

Good day, colleagues!

I'm writing application that uses Winpcap(libpcap) and I need to create Ethernet packets manually. To do this, I must know MAC addresses of local and destination machines. Suppose that destination machine is in my local network (if it's not I need to know gateway MAC).

As I understand, I can get local MAC with the help of @QNetworkInterface::hardwareAddress ().@ But getting MAC of remote machine is not so obvious. Can I do it with the help of QT or I must use system commands or packet capturing?

andre

I don't think you can expect help from Qt on this. You will need to use system commands.

ZapB

I do not know of anything within Qt that provides this level of information so I think that you will need to use some platform-specific code.

usamytch

Thank you for the answers, I'll go to the system commands.

ZapB

OK, QProcess and arp spring to mind.

rich

If you're creating raw packets anyway then just create an ARP request for the target IP address and look at the mac address in the ARP reply.

usamytch

Thank you, on Windows @arp -a <IP>@ did the trick.

ZapB

[quote author="rich" date="1302263107"]If you're creating raw packets anyway then just create an ARP request for the target IP address and look at the mac address in the ARP reply.
[/quote]

I agree that this is probably a better way to go eventually - especially if this will be done for huge numbers of devices as launching processes is expensive. I just suggested QProcess and the arp tool as a way of getting something up and running quickly.

? This user is from outside of this forum

Code examples for arp -a might be found here...
http://beej.us/guide/bgnet/output/html/multipage/index.html